Avi Loeb Medium

(Image credit: The Spectator)During one of the dozen television interviews on Artemis II that I had in recent days (as summarized here, here, here and here), I made the trivial prediction that its four astronauts will witness meteor flares on the surface of the dark side of the Moon. Since the Moon has no atmosphere, objects on a collision course with it would impact the lunar surface directly rather than burn-up and disintegrate inside a fireball, as they do due to friction in the Earth’s atmosphere. This prediction came true near the end of Orion’s closest approach to the Moon on April 6, 2026, when the Sun was eclipsed by the Moon for almost an hour. During that time, the astronauts witnessed with their naked eyes six micrometeor impacts on the dark side of the Moon. It is widely believed that the Moon formed out of material ejected from the surface of Earth as a result of an impact by a Mars -size proto-planet named Theia. Upon formation the lunar surface was smooth, but as evident from the latest high-resolution images — transferred by laser communication from Artemis II to Earth — the lunar surface is scarred with numerous impact craters. The Moon serves as a museum for the material collected from these impact events, some of which was delivered by interstellar objects from outside the Solar System. What is the chance that an interstellar object like 3I/ATLAS impacted the Moon over the 4.5 billion years of its history? The calculation is straightforward. The probability for an interstellar impact equals the product of the number of interstellar objects per unit volume, N, times the typical velocity of 3I/ATLAS-like objects, V=60 kilometers per second, times the cross-sectional area of the Moon, A=9.5 million square kilometers, times the age of the Moon, T=4.5 billion years. The number density was estimated as N=0.007 per astronomical unit cubed in the latest analysis of the Hubble Space Telescope data, reported here. Altogether this product yields an impact probability of, P=(N*V*A*T) = 17%. In other words: the chance of a 3I/ATLAS-like interstellar object to impact the Moon during its entire history equals to the probability that a six-sided die cube will land on a specific face. This is a significant probability. Adopting a mass of order a billion tons for 3I/ATLAS (as estimated here), suggests that a single impact could have cover the entire lunar surface with a thin layer of interstellar dust. By now, this layer was mixed with a much thicker dust layer from accumulated impacts of numerous Solar System asteroids of the type observed by the Artemis II astronauts. An image from Artemis II of the Earth behind the Moon, showing numerous impact craters on the lunar surface. (Image credit: NASA)Since Earth has a surface area that is larger than that of the Moon by a factor of 13.5, there should have been a few impacts of interstellar objects like 3I/ATLAS on Earth. These events were likely separated in time by about a billion years from each other, implying that their imprint was buried underground by geological mixing over these long periods of time. In 2019, I co-authored a paper (accessible here) with my undergraduate student at that time, Amir Siraj, suggesting a systematic search for interstellar impacts on the Moon. The paper proposed to send a new telescope in lunar orbit in order to study in real-time interstellar impacts and to serve as a laboratory for hypervelocity collisions. We calculated that a telescope with a diameter larger than 2 meters should be able to detect at least one impact of an interstellar object with a diameter of a few centimeters among hundreds of Solar System meteoroid impacts, every year. For each interstellar object, measurements of the reflected sunlight and shadow, as well as the impact’s optical flash and crater, would allow for the determination of the velocity, mass, density, and composition of the impactor. This proposal might be realized in the coming years as part of the Artemis program to establish a human base with technological and scientific infrastructure on the Moon. Pursuing a comprehensive survey of meteor flashes would provide a new opportunity to use the Moon as a fishing net for interstellar material. Perhaps among the numerous rocks that constitute most lunar impactors, humanity will also identify crash sites of technological debris from extraterrestrial civilizations. This will constitute a new tool in the toolbox of the 66-year-long search for extraterrestrial technological civilizations. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, former director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

(Image credit: Newsmax)Today, April 8, 2026, the Artemis II spacecraft will carry the four humans who reached farther than any human did, back to their home planet, Earth. Below a transcript of a new interview I had this morning in the company of former NASA astronaut, Winston (Win) E. Scott, with the anchor Shannon Cake on Newsmax (accessible in video form here). Shannon’s questions are marked with SC, while my and Win’s answers are marked with AL and WS, respectively. *** SC: I want to bring in former NASA astronaut Captain Winston Scott and Harvard University professor Dr. Avi Loeb. Avi, I was watching your face as we were about to come to you and you were just beaming, hearing that communication. Good morning to both of you. Great to see you. So, this amazing Artemis II mission, they make this space-to-space call with the ISS yesterday. This is a milestone. It really does just highlight how far communication technology has come in space. Dr. Loeb, let’s start with you, and then we go to the captain. AL: What is really remarkable about this mission is the technology that is being used now that is so much better than the Apollo missions. Communication is far more rapid with 38 gigabytes transmitted per day, and that allows us to see beautiful images that we’ve never seen before of the Moon. In particular, we see a lot of small craters. It is possible to assess how many small asteroid impacts compared to big impacts occurred on the surface of the Moon. When the Moon formed, it was molten rock so the surface was initially completely smooth. But now, after 4.5 billion years, there are lots of craters that scarred the Moon and we can learn a lot about its history. In fact, the astronauts saw flashes of light from impacts as they passed near the Moon. But most importantly were the images of the Earth rising, because they give us a sense of how precious is the planet that we live on. When you live at home as a kid, you don’t appreciate your home as much as when you leave it as an adult and look at it from a distance. And that means a lot because we are all in the same boat. We better work together to resolve conflicts. That’s what President Trump did overnight. SC: Yeah, what a message that is. You’re right, Dr. Loeb. Well said, as you look on it our Earth is beautiful from outer space. The Earth behind the Moon, as viewed by the Artemis II crew. (Image credit: NASA)Captain Scott, I would imagine the ability to update the images of Earth from deep space. What does that mean to you to be able to bring those images back to humanity? It’s quite significant. WS: Oh, absolutely. It’s quite significant. And the progress that we have made with computing power and processing power, of course, makes that all possible. And it just enables us to conduct better and more detailed science, more detailed exploration, not only the Moon, but our own home planet. The entire mission is absolutely incredible and testament to the men and women who’ve made this possible. It’s really fun and fascinating to me that we have people on the space station a couple of hundred miles above the Earth and then people on a Moon spaceship hundreds of thousands of miles away and communicating back and forth with each other, communicating with those of us on the ground. Just incredible technology and a testament to American ingenuity and American leadership in science, technology, engineering and math. You could hear the excitement in the astronauts’ voices yesterday. This kind of moment for astronauts are being, you know, so far from Earth. SC: Who is the closest human who can really understand maybe a little bit of what I’m feeling? I have been a fly on the wall and watched you, Captain Scott, listening to that conversation. What a moment it really was. WS: Oh, absolutely. You know, words just don’t describe it. Even though I’m not there myself, reflecting back on my space shuttle missions and then listening and watching the faces from both crews is just a moment of pride for me and a moment of excitement for me. And I almost, I don’t want to use the word envy, but I’m proud and happy for these young people. I sure would love to be up there with them. Yeah, put me in, Coach. SC: I bet there were a few of those feelings running through you yesterday as you listened to the conversation and watched this incredible mission launch bring us back so much information. Let’s talk about that. The pictures from the far side of the Moon. Dr. Loeb, you were talking about them a moment ago. Incredible. So how do they unpack it a bit further for us? How do they inform you and your work, Dr. Loeb, and scientists globally on lunar geology and then even more broadly, to your point, evolution? AL: Most interestingly, the Moon suffers a lot of impacts. And some of the impacts are rocks from the solar system. Some of them are objects from interstellar space. And we can learn much more about those impacts because there is no atmosphere to burn up the objects before they impact the Moon. We should keep in mind also that the moon came from Earth. It was chipped off by a collision of. an object the size of Mars about 4.5 billion years ago. And actually, the Moon will also return to Earth in the distant future, 7.6 billion years from now, when the Sun will expand and engulf both the Earth and the moon. The drag on the envelope of the Sun will bring the moon back crashing on Earth. So, the moon is part of Earth in a way, and we are just examining the ancient conditions on Earth when we study the Moon. because not much has happened to this piece of rock. And, of course, there are lots of opportunities to put scientific instruments on the Moon, such as radio telescopes or optical interferometers because it has no atmosphere. There is no radio interference on the far side. This is in addition, of course, to national security objectives in going to the Moon. That’s what the Artemis program is aiming to do. (Image credit: Newsmax)SC: Yeah, absolutely. Captain, you know, I know that the astronauts, when they were on the far side of the Moon, they had to work of quickly. They weren’t there long, maybe seven, eight hours most, the 40-minute interval where they had no communication at all with us. But they had to really work fast and hard because the opportunity to see what Dr. Loeb has laid out, the significance of their research, that is just years and years of training of doing the same drills that may seem mundane when you’re going through your training. But when you have seven hours to pull that off, talk to me about the pressure. WS: Absolutely. And you’re right. They do spend years and years training for essentially a seven-hour period of time. And no amount of training, no matter how high the fidelity, can match the real thing. When the astronauts get there on the far side of the Moon, they have to execute these tasks in real time. There are some things that occur that you don’t anticipate in training. There may be other targets that they did not see, that something may not appear at the same angle as they saw. But in training, the cameras may not function properly. So, you are right. There’s a lot that goes into it, and there’s a lot of pressure on them. But one of the things that attracts people like the Orion astronauts and myself is that challenge. You want to get there. You want to do the job. You want to do it well. You want to be able to handle any sort of unexpected things that crop up. And based on the images that we got back, I think the crew has done an amazing job. SC: We’re going to provide a lot of great data for the geologists here on Earth to study, learn more about our Moon, about our Earth, about the evolution of our Solar System. Well, we know today that two things have popped up too, as you mentioned, Dr. Loeb, were two craters that we weren’t expecting. And I can only imagine the crew sitting there going: “wait, we didn’t know about that one.” And to your point, Captain Scott, the scramble of let me get this, this becomes your priority. They named one of them: `Integrity’, the name of the capsule that they’re flying. And then the other crater they named a very special name. I want to play a quick clip, involving the Canadian astronaut, Jeremy Hansen. You can feel the emotion from outer space, deep outer space there. Just to bring context to it, in 2020 Commander Reid Weisman’s wife, Carroll, passed away from cancer. And so, they named that crater, that bright, beautiful crater, Carroll, in her honor and to honor her children as well. What a moment, Captain, that was. WS: Absolutely. And you’re right, a very, very moving and touching moment. And I think in this case, very, very appropriate. And I’m at a loss of words as to what this all means. But I think everybody that heard that can’t help but feel a little bit of the emotion that went into the naming of that prayer, Carroll. And I do hope that from now until eternity. That name will stick and we will honor the wife of Commander Weisman and the mother of his children. SC: Meanwhile, they’re making quick work. These astronauts are getting back to Earth now. The Friday splashdown off the coast of California expected the move to enter the Earth’s gravitational pull. It is incredibly risky. Dr. Loeb, what does that look like? And then I’ll end with you, Captain Scott. AL: Right now, the spacecraft is following gravity, but it will eventually need to maneuver a bit in order to get to the right spot. These are all relatively secure procedures. I should say that it’s very appropriate to name a crater on the Moon after Carroll, but also there are 100 billion stars in the Milky Way galaxy. There is more than one star to name per person on Earth. And just think about the sky at night. The universe has much more real estate than we find here on Earth. And it opens opportunities for our future. So, it’s very inspiring. And I very much hope that the young kids watching this will be inspired to become scientists or technologists because we didn’t have that experience of humans getting so far for 54 years. SC: Captain Scott, very quickly as we had to break here, your thoughts on this tricky mission, entering the Earth’s gravitational pull, sir. WS: Yeah, well, of course, they’re already in the Earth’s gravitational pull. The telling moment is going to be when they hit entry interface. That is when the vehicle intercepts the Earth’s atmosphere. It’s somewhere around 400,000 feet. That’s when you begin to sense the drag on the capsule, when it begins to slow down and when there’s the most dangerous part. You’re going so fast that air ionizes at super-hot temperatures outside. We want the thermal protection system or the heat shield to be working properly to keep these folks safe as they reenter and parachute to the ocean. I am confident that it will all work well and we’ll welcome them back home in a couple of days. SC: From your lips to God’s ears, we will all be watching and praying. Former NASA astronaut Captain Winston Scott and Harvard University professor Dr. Avi Loeb. Gentlemen, great conversation. Good to see you. ***** (Image credit: Newsmax2)Last night, April 7, 2026, I was interviewed by the anchor Rick Leventhal on Newsmax2 (accessible in video form here). Rick’s questions are marked with RL, while my answers are marked with AL, respectively. *** RL: Joining us now is a guy who might have some answers to the burning questions of, is there life in outer space? Director of the Institute for Theory and Computation at Harvard University, Professor Avi Loeb. Professor, welcome to the show. Thank you for being here. AL: Thanks for having me. RL: So, what is the likelihood alien civilizations exist? AL: Well, first, I wanted to salute President Trump for opening new frontiers. The one that we are all familiar with is artificial intelligence. It’s becoming exponentially better over timescales of years. And President Trump is leading the way on that. The second is the rejuvenation of space exploration. The Artemis II mission is doing fantastically well. We have views of the Earth, the Moon, and the Sun that we’ve never had before. And you might wonder, how come the images are so crisp, clear? That’s because the spacecraft is transmitting 38 gigabytes per day. That’s much more than the Apollo missions ever did. So that’s a new frontier being enabled by optical communication lasers. But the third frontier that President Trump opens is the potential for disclosure of information on alien intelligence. And I should say that is the most exciting of them all because artificial intelligence is based on a training data set limited to our Earth, whereas alien intelligence is based on a training data set that comes from the universe at large. There is much more real estate beyond Earth. And so, the question is: does the U.S. government have interesting information? As you mentioned, there is a task force led by Congresswoman Anna Paulina Luna. And if we get a glimpse at what the government knows, then I would be delighted to help them figure it out. You know, that is the most exciting question in science. “Are we alone?” is also the most romantic question in science. RL: Professor, my understanding is your own research has suggested the existence of molecular oxygen on Earth-sized planets in their sun’s habitable zone. Explain to us what that means as succinctly as you can for the possibility of extraterrestrial life. AL: There are about 100 billion stars like the sun in the Milky Way galaxy alone. And about 10 percent of them have a planet the size of the Earth, roughly at the same separation. We all think that life started on Earth from a soup of chemicals on the surface. And if you start with similar conditions in billions of other places, it’s very likely that you’ll get similar outcomes. The fundamental question is, which of these exoplanets — planets around other stars, have life-as-we-know-it? We don’t know. One way to check is to find oxygen in the atmospheres of those planets. And indeed, there is a plan for a 10-billion-dollar space telescope that within two decades will be able to look for that. But there is another approach, which is to check for any packages in our mailbox. That’s a completely different approach. Maybe there is a tennis ball in our backyard that was thrown by a neighbor. Maybe there is something else. The Pentagon or the intelligence agencies might have a clue about, because if there are any probes close to Earth, they might have collected data over the decades regarding that. And, of course, some of it is classified because it was obtained by classified sensors. But there might be other data that could be declassified. I would love to look at it. I am leading the Galileo project that is collecting new data using new observatories that we constructed. We also went to an expedition to the Pacific Ocean to collect materials from an interstellar object. So, there is a lot to do. But overall, I think this is information that we should share with the public because, we are all in the same boat here on Earth. That’s the message we got from Artemis II. RL: Couldn’t agree more. Professor Avi Loeb, unfortunately, we have to leave it there because of all the breaking news. But we appreciate your joining the show. And let us know if you find any aliens. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, former director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

A view through the Orion capsule window. (Image credit: NASA)Recent filing with the U.S. Federal Communications Commission (FCC) on January 30, 2026, (here) imply that Elon Musk’s SpaceX has proposed a massive “orbital data center” constellation of up to one million satellites in low Earth orbits (as reported here). Putting aside the severe light pollution from this constellation to astronomical observatories worldwide, the physics behind this initiative makes little sense. Refrigeration in space is more challenging than on Earth because standard systems rely on gravity to manage liquids and gases. With much lower gravity, the oil used to lubricate traditional compressors can clog the system, and heat cannot rise away from components through natural convection (as discussed here and here). Given the solar flux of about a kilowatt per square meter, the envisioned total system power of 100 gigawatts requires an effective area of 100 million square meters in solar panels, altogether making a construction that measures ten kilometers on a side. Splitting the collecting area between a million components still requires that each component will have a solar array that is ten meters in length. A linear alignment of just ten components stretches across roughly the full height of the Artemis II Space Launch System rocket (98 meters). A million satellites in low Earth orbit pose a serious risk for collisions, where the debris would catastrophically trigger a cascade chain reaction of collisions with fragments through the so-called Kessler Effect (as discussed here). The burning debris would have bad consequences for the Earth’s atmosphere and ground. The timeline for the construction of this constellation will likely be lengthened by the current challenges facing Starship. Building a suitable factory on the Moon will probably take many decades. The use of an electromagnetic catapult to launch the satellites is an unproven technology. The entire project sounds more like a speculative science fantasy than a believable technological project. But speaking about science fantasy, the imagined constellation represents a miniature version of a Dyson Sphere, a concept envisioned in a 1960 paper here by the physicist Freeman Dyson who suggested that advanced technological civilizations might wish to harness a larger fraction of the energy output of their host star than their parent planet intercepts. In 2023, I published a paper here which suggested that as the host star brightens up during its natural evolution, it might separate Dyson sphere components apart and launch them to interstellar space. There, the pieces of a broken Dyson Sphere may appear as thin interstellar objects which are pushed around by radiation pressure, similarly to the behavior of the first recognized interstellar object 1I/`Oumuamua (as described here). If Elon Musk will get his way through the FCC, then billions of years from now — the brightening Sun (as calculated here) might push such space relics out of the Solar System where extraterrestrial astronomers might find them with their telescopes. Elon Musk is probably not the most accomplished space entrepreneur in the Milky-Way over the 13.8 billion years that elapsed since the Big Bang. *** Space exploration remains an inspiring reality. Through the 38 gigabytes per day of data streaming from Artemis II through laser communication, we are able to see amazing photographs of the Moon, Earth and sunset from the far side of the Moon. May humanity live-long and prosper in space! Three views of Earth behind the Moon, as viewed by the Artemis II crew. (Image credit: NASA)Eclipse of the Sun by the Moon, as viewed by the Artemis II crew. (Image credit: NASA)ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023) Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, former director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

(Image credit: Newsmax)Today, April 6, 2026, the Artemis II spacecraft will carry four humans to a distance of 406,773 kilometers from Earth, the farthest humans has ever gone before. In celebration of this accomplishment, I attach below a transcript of two recent interviews I had in the company of former NASA administrator, Jim Bridenstine with the anchor Shannon Cake on Newsmax (accessible in video format here and here). Shannon’s questions are marked with SC, while my and Jim’s answers are marked with AL and JB, respectively. *** (Image credit: Newsmax)Pre-launch episode (April 1, 2026): Humans are going deeper into space than ever before — Avi Loeb and former NASA Chief Jim Bridenstine. SC: Former NASA Administrator Jim Bridenstine is joining us along with Professor Avi Loeb, the director of the Institute for Theory and Computation at Harvard University. Thanks to both of you for being with us. So, Dr. Loeb, I feel like the image that we’re getting at NASA right now is perfect for your title involving theory and computation. That’s a lot of computation going on. I think as we look on at the screen. I’m hoping you can see it too, sir. But the astronauts have been prepped. It appears they’re in their seats. There is a whole lot of controls. That is way too much for my simple math brain. But, sir, walk us through what’s happening here on the screen. AL: This is an amazing feat that for 54 years we have been waiting for. I’m ten years older than that but there are many people that were born after the last long flight into space. And it’s really inspiring for humanity to contemplate going to space. And I hope it will open a new page in our space exploration, of settling people on the Moon. But going beyond that, there are discussions of going to Mars. There might be space platforms that carry humans to even longer journeys altogether. I think we should not keep our minds only on what happens on this rock that we were born on. We are often engaged with what happens here on earth through geopolitics. But it’s far more inspiring to go out to space because that would obviously be important for the long-term survival of humanity. What we are seeing is lots of details about the maneuvering of the rocket and, and how to engage with the data that comes in. And that involves computers that nowadays are far better than were used 54 years ago. We have much better technologies, but we’ve never practiced them in recent history. And Artemis II will be followed by additional launches, Artemis III and eventually settling on the Moon, bringing a nuclear reactor there, also establishing infrastructure and perhaps scientific endeavors that, the Moon is a much better platform for. There is no atmosphere there. There is no seismic noise. There are many benefits going there. One obviously is to maintain the technological superiority of the U.S., carrying the torch forward for the entirety of humanity. SC: Yeah, I’m glad you mentioned that. The importance of getting back there first, right before anyone else. Administrator Bridenstine, we were talking with you and watching the prep go on. And sir, as you see something, please jump in and tell our audience what you’re seeing and what’s significant about it. But these astronauts, they are traveling farther from earth with a possible Moon landing in 2028. JB: I may borrow the language from the past. It’s the right language. This is a leap forward. We need to own it. This is a great moment for the United States of America. You can see that the astronauts are in those orange spacesuits. They’ve got their helmets on. That’s because when this vehicle launches, it is a pressurized capsule and it’s going into the vacuum of space. But if it loses pressure, you’ve got the backup system, which is your spacesuit. Those orange spacesuits are a safety function. And then you’ve got the screens that they’re manipulating. They’re doing all kinds of checks and tests. And back in the fire control room, they’re communicating with all kinds of engineers and operators that are also going through systems, checks and tests. And tonight it’s going to launch to space. Now, it’s also true those orange spacesuits are not the same spacesuits you would use to walk on the Moon. We do need to go to the surface of the Moon. Jared Isaacman, the current NASA administrator, has said we’re going to build a Moon base. Well, that means we need spacesuits for walking on the surface of the Moon. It’s an entirely different spacesuit, which is also different than a spacesuit for a spacewalk. But we’re going to learn all kinds of things on this flight. The astronauts, of course, are going to test the control systems to make sure that they can do what’s called rendezvous and proximity operations, ultimately for the purpose of docking to a human landing system that can go down to the surface of the Moon. And we’re going to be testing all of the ways that we live and work in space for a period of ten days, well beyond the Van Allen radiation belt into deep space, where there’s some harsh radiation environments. But it’s only a ten-day mission, and they’re going to learn lots of data about the radiation environment around the Moon as well, bring back that data and hopefully get us prepped for 2028. SC: Dr. Loeb, I have about 30 seconds left, sir. Just speak, if you will, and close this out. As you look at the screen, the importance of this mission, what you hope it brings and perhaps the energy in the space race that it brings to all of us, right? AL: The U.S. definitely has to win the space race. This is inspiring for all humans on Earth. As of now, we are only contemplating round trips, but in the distant future, there will be humans that will go to these destinations on a one-way ticket, and that would be a very different trip. And hopefully they’ll have the infrastructure, the resources to stay there for a while and develop technologies and infrastructure that are really at the forefront. And as of now, we haven’t used, for example, artificial intelligence in space. We can start using that in the coming years. SC: This takes you to a whole other level, doesn’t it? Jim Bridenstine and Professor Avi Loeb, great conversation, gentlemen. Thanks for watching walking us through this. (Image credit: Newsmax)Moon Flyby episode (April 6, 2026): Artemis II To Make a Historic Lunar Flyby — Avi Loeb and former NASA Chief Jim Bridenstine. SC: Former NASA Administrator Jim Bridenstine, is joining us this morning. Also with us today, the Director of the Institute for Theory and Computation at Harvard University, Professor Avi Loeb. Gentlemen, good to see you both. Jim, the Artemis II crew getting ready for this lunar flyby. This is the farthest humans have traveled from Earth, surpassing the Apollo 13 record more than 50 years ago. The lead of NASA’s Artemis crew explains just how far they’ll reach. Listen to this. “And then to come in for that injection, we came all the way back to Earth again. We were out there at 60,000 kilometers. We came back to within 200 kilometers of the planet. And it just felt like we were falling out of the sky, back to Earth. And I said to Reid, it feels like we’re going to hit it. It’s amazing that we’re actually going to go around and miss this thing.” SC: But they didn’t. They took off once again. But boy, so close to home, right? How incredible historic is this achievement? Jim, let’s start with you. JB: Obviously this is what it’s all about tonight. Obviously, we have the launch, which is super exciting. We’re going to have the entry, descent and landing, which is also exciting. But the mission is really about going to the Moon. And tonight we go to the Moon. The astronauts are going to see an Earth set and they’re going to see an Earth rise. At the same time, while they’re behind the Moon, it’s going to be a blackout. They’re not going to have a signal. And so that means for a period of 40 minutes, our astronauts are not going to be able to communicate back to the Earth. But in that time, records are going to be broken. They’re going to fly closer to the Moon than at any point on this journey. And at the same time, they’re closest to the Moon. They’re going to be farther from the Earth than any humans in the history of the Earth, which is a magnificent achievement. So, there are so many different things that are going to happen tonight. This is what it’s all about. We are super excited about it. SC: Absolutely we are. Dr. Loeb, let me bring you into the conversation. Tell me, what are they going to have to work fast. As Jim just laid out, there is a lot of things happening simultaneously and the window is short. What are they trying to capture and how significant is it? AL: This is a very exciting day. One day after rising to the Moon on Easter, the astronauts will observe the Moon’s far side from about 4,000 to 6,000 miles away, viewing never seen before terrain, including craters, frozen rock flows and massive basins. And they will document high elevation craters, ancient volcanic structures, potential meteorite impact flashes. Altogether, it would be also exciting for our scientific understanding of the Moon. But all in all, this is the first step in coming close to the Moon. The next step is such a mission with the lander and ultimately establishing a base on the Moon with a nuclear reactor and with scientific infrastructure. And frankly, I will be delighted to go on a one-way trip to the Moon once the infrastructure is there. SC: Would you really? I think I’d want to be able to come back. I don’t know about you, Jim. One way. But that’s what we’re going for, right? That’s kind of the plan is to be able to, you know, see what we can do to set up on the Moon. On board the Orion, Jim, the crew practiced putting on these pumpkin-colored pressure suits in case of emergencies. They did that in the last 24 hours. What kind of situations could or would arise that would necessitate that? JB: Well, imagine if they were to hit like a micrometeoroid or something and they lost pressure for a period of time. The capsule is designed to quickly create more pressure so that not all is lost. But at the same time, they’ll need to quickly put on their spacesuits, which, of course, are designed to be pressurized so that they’ll have everything they need to survive and come home safely in their pressurized suits. So that’s what that’s all about. They’re practicing now. You’ll see them wear the suits on launch and on reentry just in general, but they also practice around the Moon. I would also say when we talk about this lunar base that we’re going to build, our astronauts tonight are going to look down and they’re going to see portions, small slivers of this south pole of the Moon. That’s where there’s hundreds of millions of tons of water ice, which, of course, is not just water to drink. It’s also oxygen to breathe and its hydrogen for fuel. And all that is present on the south pole of the Moon. So, they’re looking for opportunities for the future to land and build that lunar base. SC: Wow. Let’s talk about that, Professor, a little bit further. You were talking about the plan, the stages. Artemis III would then launch and test rovers, if I’m understanding that correctly, and then perhaps, you know, get maybe boots back to the Moon again with Artemis IV. Is this what the plan is, and are we on track? AL: Yes, but it’s a very different plan than the Apollo missions in the sense that the idea is to establish a base, establish the superiority of the United States technology and science in leading humanity into space. And that means putting also scientific infrastructure there. There are various proposals for taking advantage of the lack of an atmosphere on the Moon and the lack of any seismic noise from earthquakes and so forth. Altogether, it’s an amazing opportunity as a first step towards Mars. Eventually, we might go to Mars. These are two rocks that happen to be closest to Earth that nature gave us an opportunity to land on. But ultimately, the way I see it is the initial steps towards establishing a space platform that carries humans or robots with AI out of the solar system. You know, the Milky Way is a far greater landscape. There is much more real estate out there, and it’s for humanity to take. SC: It is extraordinary to think about when you lay it out like that and the incredible opportunity. Jim, I know that NASA, they scrapped a planned trajectory correction over the weekend. What was that about? And does it mean that they’re back on course and there’s no longer any sort of threat? And was there ever a threat? JB: Oh, no, they just hit the numbers so perfectly. They didn’t have to actually do a course correction which is remarkable. What that means is that the systems are working. They’re working exactly how they’re supposed to work, and they didn’t need a course correction. All of that, I think, is very, very positive news. It actually is good for saving fuel for future missions. We can have even better confidence on how our systems operate and the data that we’re able to collect and utilize in these missions. Just to be clear, Artemis III is going to be a mission to Earth orbit, where the Orion crew capsule is going to interact in Earth orbit with a landing system for the Moon. And Artemis IV and V are intended to be Moon landings. So, there’s a rapid sequence of events that’s going to happen here. And it’s going to require all of America to get behind us to move as quickly as possible. Because the goal is, in fact, to not just orbit the Moon, but land on the Moon before China and start operating a lunar base on the South Pole. It has been really exciting to see new life really back in NASA’s lungs and then the partnership that has also occurred with private industry. SC: Final thoughts, Dr. Loeb. We have a few seconds left. AL: Clearly the technology that is being employed right now is far better than back in the 1960s and 1970s. For example, about 38 gigabytes of data are being transmitted per day from Orion. That’s why we see such beautiful images. This laser communication will be very useful in the future for quantum computing and communication infrastructure. There are lots of technological advances being used on this mission, and we should all salute NASA for doing such a fantastic job. SC: It’s been fun to watch and much more to come, and it’ll be an exciting day, I know, for the two of you and the entire world. Former NASA Administrator Jim Bridenstine, Director of the Institute for Theory and Computation at Harvard University, Professor Avi Loeb. Gentlemen, thanks so much. I had a great conversation with you last week when I hosted another show, and I asked our team to bring you both back. It’s really wonderful to have you on the morning with us. Appreciate your time, always. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, former director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

(Image credit: Newsmax)Below is the transcript of an interview I had this morning in the company of Olympia LaPoint with the anchors Bill Spadea & Krysia Lenzo in Wake Up America on Newsmax (accessible in video format here). Bill and Krysia’s questions are marked with WS and KL, while my and Olympia’s answers are marked with AL and OL, respectively. *** The Artemis II crew will fly around the Moon tomorrow. Let’s discuss this with Harvard University professor Dr. Avi Loeb. We’re also joined by former NASA rocket scientist and author of Answers Unleashed, Olympia LaPoint. WS: Welcome, guys. Great to see you both. Happy Easter! Professor, let’s start with you. Artemis II is going to fly around the far side of the moon tomorrow. Eventually, President Trump wants NASA to set up a moon base. How would you rate the mission so far, and is a moon base realistic? AL: Thanks for having me. This mission has been a spectacular success so far and in line with the vision of President Trump of bringing humans back to the moon and, in fact, in a much more prominent way than the Apollo missions did. This opens a new frontier of space exploration where there will be some infrastructure on the Moon. As the Artemis II spacecraft comes closer to the Moon, the Moon gets bigger in its windows, and the crew will get there, as you said, tomorrow. At some time during the day, we will lose contact with the astronauts because they will hide behind the Moon relative to Earth. And they could see the sunset behind the moon as well. Altogether, this mission is aiming at testing various maneuvers and procedures that will be very helpful when we get to Artemis III and future missions that will bring humans to the Moon by combining an encounter of this type with a lander. And we very much look forward to that. KL: Olympia, visiting the moon is a long-term goal of President Trump before eventually landing on Mars. That could happen. How impressed are you with the way NASA made this happen so fast? OL: Thank you all first for being on this show on Easter. I am extremely impressed with the science of this particular trip. People are not aware of the great science innovation that is specifically happening with this Artemis II trip. For example, we are testing RS-25 engines, and these are engines that can burn as hot as the temperature on the surface of the Sun, and have the same pressures as the very bottom of the ocean. So that’s the type of technology we are looking at with the engines. We are also looking at the Orion crew capsule. This crew capsule is being tested right now to ensure that the capsule can transport people safely to the outer edges of deep space where it’s not as easy to come back to Earth. This capsule is also going to be tested when it comes back into the Earth’s atmosphere. Next, the optical communications are going to be tested and what is truly impressive with this particular launch is the laser communications as well as the 4K communications that are going to define the next trajectory of quantum computing and quantum artificial intelligence communications. What we are also looking at, which is just completely amazing, is life sustaining air systems. For anyone going to that location in space, there are air systems so that people on this particular Orion craft and this Artemis rocket are able to breathe fresh air for long periods of time. So, when I look at this particular launch, I am impressed with the science that is in this launch, and I’m excited for everyone on board. (Image credit: Newsmax)WS: Dr. Loeb, let us talk just quickly about the kids today. They all want to be on YouTube, but do you think this mission could inspire a lot of kids to take up the sciences, maybe get into NASA or SpaceX in the future? AL: I surely hope so. I think it’s about time to give up on the addiction to digital screens. And personally, I would love to take a one-way ticket to space, go to the Moon if there is infrastructure there. We are entering a new era. Of course, it’s a new age of artificial intelligence, but it’s also a rejuvenated age of space exploration. And I should mention that it’s also a potentially new age of perhaps discovering alien intelligence. That’s another directive that President Trump gave. WS: Thank you, Dr. Avi Loeb and Olympia LaPointe. Happy Easter. Appreciate you. Happy Easter. (Image credit: Newsmax)ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, former director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

Logarithm (base 10) of the abundances of carbon (vertical axis) and iron (horizontal axis) relative to their solar values (calibrated by hydrogen). The most metal-poor star known, SDSS J0715−7334, is shown as a large red star. It is deficient in both carbon and iron. (Image credit: A.P. Ji et al. 2026)The first generation of stars formed out of pristine gas of hydrogen and helium, the primordial gas left over from the Big Bang; for details, see my textbooks titled “How Did the First Stars and Galaxies Form?” here and “The First Galaxies in the Universe” here. Nuclear fusion in the interiors of these stars created heavier elements leading all the way to the most stable nucleus in nature, iron. Since life-as-we-know-it relies on carbon and oxygen, our cosmic roots stem from the nuclear fusion reactions in the hot cores of these first stars. The nuclear burning ultimately converted the initial fuel of early massive stars to heavy elements, with the most stable element, iron, in the middle, surrounded by “onion shells” of progressively lighter elements in the outer layers. The envelope of heavy elements was expelled to interstellar space through supernova explosions once the nuclear fuel was consumed and the core collapsed to the scale of a city — ejecting the outer envelope through the release of its acquired gravitational energy. In a Nature paper (accessible here) that I co-authored in 2003 with my former postdoc, Volker Bromm, we explained that the first stars in the Universe should have been much more massive than the Sun. Inefficient cooling of the primordial gas through molecular hydrogen yielded fragmentation into clumps, each with at least a few hundred solar masses. But as soon as the primordial gas was enriched with heavy elements by supernova explosions to a carbon or oxygen abundance as small as ~0.01% of that found in the Sun, cooling by carbon or oxygen atoms could have led to the formation of low-mass stars by allowing fragmentation to smaller clumps. The earliest supermassive stars of a few hundred solar masses were short lived, lasting only a few million years and leaving behind black holes. But stars with a mass comparable to that of the Sun may still be around today. The atomic cooling by carbon and oxygen naturally accounts for the known population of solar-mass stars in the halo of the Milky-Way galaxy with extremely low iron abundances but with a modest carbon abundance. Such stars are deficient in iron and may therefore be regarded as `anemic’. But their substantial carbon content explains how atomic cooling led to their formation. How did their unusual abundance pattern form? Carbon-enhanced, iron-deficient stars could have been enriched by a supernova explosion that ejected the outer layers of a dying star, including carbon, while draining most of the iron in its core into a black hole. This week, a new Nature paper (accessible here) reported the discovery of the most metal-poor star known, SDSS J0715−7334. This cool, red-giant star with a surface temperature of 4,700 degrees Kelvin, shows an iron abundance which is 10^{−4.3} of the solar value and a carbon abundance that is 10^{−4.5} of the solar value. It is deficient in both iron and carbon. Altogether, the heavy elements make up a tiny fraction, 7.8 × 10^{−7}, of the total mass of the star, requiring a formation channel mediated by cooling of dust particles, since atomic cooling is not sufficiently effective. The heavy element abundance pattern of the star can be explained by a primordial supernova explosion of a progenitor star with an initial mass of 30 solar masses. The orbit of the star implies that it originates from the halo of the Large Magellanic Cloud. The orbit of the metal-poor star SDSS J0715−7334 over the past 4 billion years in Galactocentric coordinates on the sky, including the gravitational influence of the Large Magellanic Cloud (LMC). (Image credit: A.P. Ji et al. 2026)The star SDSS J0715−7334 is much more chemically pristine than the earliest galaxies discovered so far by the Webb telescope, with the record holder galaxy — reported here — found when the Universe was 280 million years old — merely 2% of its current age. When I started this field of research in the early 1990s, the earliest galaxies known were a few billion years old. The Webb telescope pushed the time horizon of known galaxies by a factor of ten closer to the Big Bang. My theoretical work over the past three decades forecasts that the earliest stars formed about 70 million years after the Big Bang, so there is discovery room left to more ambitious space telescopes. Their future data will hopefully shed new light on the scientific version of the story of genesis: “Let there be light.” ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, former director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

A paragraph from a poem titled “Other Castaways” by Alan Wagstaff. (Image credit: Alan Wagstaff)Comet and asteroid experts were trained on a data set that includes icebergs and rocks. But they did not read the memo that over the past fifty years humans produced another type of space objects, technological in origin. The farthest human-made object is Voyager 1, launched in 1977 and currently at a distance of about a light day from Earth. Within a billion years, Voyager 1 will be on the opposite side of the Milky-Way galaxy relative to the Sun, as calculated here. The simplest assumption is that similar circumstances lead to similar outcomes. Astrobiologists argue that terrestrial life started from a soup of chemicals in liquid water. Given that there are likely billions of Earth-Sun analogs in the Milky-Way galaxy, it is arrogant to argue that NASA is the only space agency in our galaxy or that Elon Musk is the most accomplished space entrepreneur since the Big Bang, during 13.8 billion years of cosmic history. The star formation history of the Milky-Way, as reconstructed here from the age distribution of white dwarf remnants, implies that most sun-like stars formed billions of years before the Sun. The fact that we are late relative to others on the cosmic scene implies that Voyager 1 analogs could have traveled from the other side of the Milky-Way to our vicinity by now. Alien spacecraft more advanced than we used in the 1970s propelled to a speed faster than 30 kilometers per second, could have made it to our backyard even earlier. It therefore makes sense to examine interstellar objects for anomalies that might flag a technological origin. Natural rocks are likely far more abundant in interstellar space, but technological gadgets might be concentrated in the habitable zone of the Sun similarly to flies clustering around a lamppost. How will we know if an interstellar object is technological? It is most straightforward to identify alien tech based on a high-resolution image, but it could also be deduced from the detection of artificial lights (as discussed here), non-gravitational maneuvers that cannot be explained through natural cometary outgassing (as discussed here) or components that were designed for particular technological functions. It is also important to allow for imposters which behave like Trojan Horses (as discussed here) while displaying the outside appearance of a natural rock or an iceberg which conceals a technological interior. Obtaining a high-resolution image of interstellar objects does not necessarily require coming close to them, but could also be accomplished by an astronomical optical interferometer on the Moon, larger than a football field (as proposed here). The search for technological objects is qualitatively different from the search for electromagnetic signals, the hallmark of traditional SETI. Whereas the latter resembles waiting for a phone call, the former focuses on searching our backyard for a tennis ball or checking our mailbox for a package. In contrast to training our telescopes on distant sources, the study of interstellar objects focuses on the vicinity of Earth. If successful in finding technological products, this search will answer Enrico Fermi’s question: “where is everybody?”, with: “right here.” Whereas electromagnetic signals propagate at the speed of light and escape out to the distance of the Andromeda galaxy after crossing Earth when the first humans emerged a few million years ago, technological artifacts are bound by gravity to the Milky Way and accumulate over time in interstellar space like plastics in our oceans, as long as their speed does not exceed 500 kilometers per second — the local escape speed from the Milky-Way. The discovery of interstellar objects ushers in a new frontier in astrobiology. Even if we restrict our attention to only comets that originated naturally in distant planetary systems, these icebergs may carry materials with the building blocks of life. Indeed, the SPHEREx Space Observatory revealed organic molecules in the gas plume around 3I/ATLAS, raising the fundamental question of whether it carries life, as I discussed here. Delivery of a material sample from an interstellar object, as done by the OSIRIS-Rex mission to the solar-system asteroid Bennu (and described here), would require an ambitious intercept mission in the future. Material samples could also be collected from interstellar objects that collide with Earth and appear as meteors. If the surge in meteor activity on Earth in recent months (as described here) was associated with debris from the interstellar object 3I/ATLAS when the Earth came closest to its path, then analysis of related meteorites could unravel the composition of 3I/ATLAS. Expeditions to interstellar meteor sites, like the one I led in June 2023 (as described here), could accomplish the same task. My research team is currently analyzing isotopes from the expedition material to test whether it has an extrasolar origin, and we hope to conduct a future expedition to other interstellar meteor sites in the future (as described here). The discovery of technological signatures in the strewn fields of interstellar meteors would not only reveal the existence of life, but also extraterrestrial intelligence. Alien intelligence is far more exciting than artificial intelligence (AI), because it is based on a much larger training dataset. Among many anomalies (listed here), 3I/ATLAS entered the Solar System within 5 degrees of the ecliptic plane and offered an unprecedented opportunity for intercept missions, which humanity missed. We should seize similar opportunities with future interstellar objects, expected to be discovered by the NSF-DOE Rubin Observatory in the southern sky and the Argus array in the northern sky (as discussed here). Technological markers are initially flagged by scientists as anomalies, because they deviate from the expected behavior of rocks or icebergs. On September 17, 2020, the Pan-STARRS telescope in Hawaii discovered an object, labeled 2020 SO, which did not show cometary activity but exhibited a non-gravitational acceleration away from the Sun as a result of the reflection of sunlight from its surface. This behavior resembled the features of the interstellar object 1I\`Oumuamua, discovered by the same telescope three years earlier (as reported here). The spectrum of 2020 SO indicated that it is made of stainless steel, clinging the case that it is the upper stage of the Surveyor 2 mission launched by NASA in 1966. On January 2, 2025 the Minor Planet Center catalogued a near-Earth asteroid, only to realize that it follows the path of the Tesla Roadster car launched by SpaceX as a dummy payload on the Falcon Heavy rocket in 2018. These were identified as human-made objects because we know of what humanity launched to space over the years. But objects with similar anomalies that were launched by extraterrestrial civilizations will be catalogued by astronomers as rocks of a type never seen before. The Pavlovian response to catalog anomalous interstellar objects as comets or asteroids should be resisted. Only astronomers whose training dataset includes technological space objects, will allow themselves to flag anomalies associated with technological interstellar objects. So far, 3 interstellar objects were discovered through telescopes and at least 2 interstellar meteors were discovered by U.S. government sensors (as reported here and here). Some of these object, like 1I/`Oumuamua (as discussed here) and 3I/ATLAS (as discussed here), display multiple puzzling anomalies that could be of technological origin. Better future data could trace technological fingerprints that are beyond any reasonable doubt, but it will be recognized only if astronomers will not shove anomalies under the carpet of traditional thinking. We should be motivated to collect such data by raw curiosity, and attend to anomalies in order to gain new knowledge. Humility is a prerequisite to discovering that we are not at the top of the cosmic food chain. The foundation of science is the humility to learn, not the arrogance of expertise. Of course, many extraterrestrial artifacts may have passed near Earth throughout its 4.54-billion-year history and some of these encounters might have been documented in old texts. But science requires quantitative data from well-calibrated instruments. Astronomy departments are usually smaller in size than political science or economics departments. This is because astronomical events usually do not have major implications for society. If a star explodes a billion light years away, it does not affect our daily life. However, a visitor to our backyard could have a major impact on humanity’s future, especially if it is a technological mothership that releases mini-probes towards Earth. Following the discovery 3I/ATLAS on July 1, 2025, I defined the so-called Loeb Classification Scale of interstellar objects, where a rank of 0 corresponds to a natural object and a rank of 10 implies alien technology that poses a major threat to humanity (as quantified here, here and here). Subsequently, 3I/ATLAS was discussed as a possible black swan event within governments. In particular, the CIA did not deny having records on it (as discussed here) and Vladimir Putin mentioned it in a press conference reviewing 2025 (as discussed here). Unidentified anomalous phenomena (UAP) are the focus of 46 videos requested from the Pentagon by congresswoman Anna Paulina Luna last week (as discussed here). It would be fascinating to review the data that these videos entail. Disclosure of alien probes from an extraterrestrial technological origin could disturb financial markets and upset the sense of security promised by governments to their citizens (as discussed here). It could also fundamentally shake our world model about our place in the Universe. Cosmology textbooks (like mine here and here) describe the cosmos as a lonely place, filled with inanimate matter that follows deterministically the laws of physics. However, having siblings in our family of intelligent civilizations could change our perspective about humanity’s central role on the cosmic scheme — even more so than the Copernican revolution did. The implications would undoubtedly spill over to spiritual and religious beliefs. It might be as easy to find the closest aliens as it is to find the farthest galaxies, if we only put our mind to the task. My sentiment inspired a poem, titled “Other Castaways” and posted here, that I received before my morning jog at sunrise today from a brilliant poet in New Zealand, Alan Wagstaff. Check it out. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

A Hubble telescope image of the Jupiter-family comet 41P/Tuttle–Giacobini–Kresak, integrated over 3,840 seconds in December 2017. The right panel adds brightness contours from the gas plume around the comet. Direction arrows indicate the antisolar direction (–S) and the projected negative velocity vector reltive to the Sun (–V ). (Image credit: D. Jewitt 2026)In a new paper published here, the accomplished astronomer David Jewitt reported about an unprecedented behavior of the Jupiter-family comet 41P/Tuttle-Giacobini-Kresák. The report uses archival data collected by the Hubble Space Telescope on December 11–14, 2017, coincidentally about a month after the discovery of the interstellar object 1I/`Oumuamua. This comet, which likely originated in the Kuiper Belt and was flung into its current trajectory by Jupiter’s gravity, is now visiting the inner solar system every 5.4 years. It is well known that the spin of cometary nuclei changes as a result of the rocket effect from torques induced by outgassing. The nucleus of 41P/Tuttle-Giacobini-Kresák exhibited dramatic rotational changes when it passed near the Sun in April 2017. Eight months later, the combination of Hubble imaging and measurement of non-gravitational acceleration implies a nucleus diameter of about a kilometer (± 200 meters). Systematic brightness variations are consistent with a rotation period of 0.60 (± 0.01) days, substantially different from periods measured earlier in 2017. Data from NASA’s Neil Gehrels Swift Observatory in May 2017 implies that the object was spinning three times slower than in March 2017 when it was observed by the Discovery Channel Telescope at Lowell Observatory in Arizona. The Hubble images from December 2017 detected the comet spinning much faster again, with a period of approximately 14 hours, compared to the 46 to 60 hours measured by Swift. The simplest explanation is that the comet continued slowing until it almost stopped, and was then forced to spin in the near-opposite direction by outgassing jets from its surface — induced by solar illumination of surface ice. Jets of gas streaming off the sublimated pockets of ice can act like thrusters and if these jets are unevenly distributed, they can change the spin of the comet. Rotational frequency of 41P/Tuttle-Giacobini-Kresák as a function of time expressed as Day of Year in 2017. Frequencies above (below) the dashed horizontal line are prograde (retrograde). The date of perihelion is indicated by a dashed vertical line. (Image credit: D. Jewitt 2026)The spin of the nucleus likely reversed between perihelion in April 2017 and the post-perihelion observations in December 2017 as a result of torque from outgassing jets. The brightness variations indicate a projected axis ratio of about 1.4 to 1, while the active fraction of the nucleus decreased by a factor of 17. The physical lifetime of this small nucleus to spin up is short compared to the reported dynamical time spent in the current orbit — which is estimated to be about 1,500 years. The inferred mass loss rate from outgassing means that the object should have evaporated or broken up by rapid rotation long ago. Its observed activity should have destroyed it. As a result, the data constitutes a major puzzle: how did the object survive over the long lifespan of its orbit? Jewitt suggests two possible explanations to this puzzle. The nucleus could have been observed by the Hubble telescope during a state of unusually strong activity, leading to an overestimate of the average mass-loss rate and outgassing torque and resulting in an underestimate of its physical lifetime. Alternatively, the nucleus could be the surviving remnant of a larger body for which outgassing torques were less effective. But there is a third possible interpretation. Perhaps 41P/Tuttle-Giacobini-Kresák is a Trojan Horse with the outside appearance of a natural iceberg but with technology embedded in its belly. In that case, its spin reversal is a technological signature. Based on my personal experience — if Jewitt were to discuss this technological possibility, his paper would have been blocked from publication. Indeed, this possibility is not mentioned in the published paper, but I am free to mention it here in the absence of gatekeepers — within the safe space of my essay. Whether spin reversal is a technological signature or not, the Hubble data from 2017 on 41P/Tuttle-Giacobini-Kresák constitutes the first reported evidence for an apparent spin reversal of a comet. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

A photo of Earth from NASA’s livestream of the Artemis II’s Orion spacecraft. (Image credit: NASA)We live through exciting times in a new age of artificial intelligence (AI), a new age of disclosure about alien technologies and a rejuvenated age of space exploration, all led by the United States of America. However, most people did not get the memo as of yet. The faint response from the general public to the Artemis II renewal of human exploration of the Moon, reminded me of the title of Milan Kundera’s book: “The Unbearable Lightness of Being”. What could be more inspiring than exploring real estate beyond Earth, yet most earthlings were consuming terrestrial content on their digital screens when four astronauts blasted off from the Kennedy Space Flight Center in Florida on April 1, 2026 for a historic 10-day mission to circumnavigate the Moon. This is the first time astronauts return to the vicinity of the moon in 54 years on a trip that goes farther from Earth than any human ever has, breaking the Apollo program’s distance record. For now, all human journeys to the Moon were round trips. After humans settle there, there would also be one-way trips. So far, we never employed AI in space, but future missions will likely be navigated and guided by AI rather than being `helicopter-parented’ by NASA engineers. Does the public show fatigue from uninspiring 54 years lacking deep space exploration by humans? Or is it the obsessive distraction brought about by social media and digital screens? Either way, the current state-of-affairs could provide an answer to Enrico Fermi’s question: “where is everybody?” which is: “many of the extraterrestrials are glued to their digital screens and not interested in venturing beyond their home planet where they will perish.” What could ignite the flame of space exploration here on Earth? My hope is that it will be the discovery of alien technology. If we realize that alien products visit our back yard, we might be intrigued to imitate them and visit the sender’s back yard with our probes. Yesterday, the brilliant congresswoman Anna Paulina Luna, who chairs the “Task Force on the Declassification of Federal Secrets,” sent a letter to the Secretary of War, Pete Hegseth, requesting 46 video files related to sightings of Unidentified Anomalous Phenomena (UAP). This request was inspired by President Trumps visionary directive to Secretary Hegseth from February 20, 2026 (as discussed here). Why is the UAP topic not getting full attention within the mainstream of the scientific community, as it should? What could ignite the flame of UAP research? My hope is that new discoveries from the Galileo Project research team under my leadership could deliver the much-needed change. Stay tuned. In a Newsmax interview about the Artemis II launch that I had this morning in the program National Report, I had mentioned that the film director Steven Spielberg asked me to let him know if I discover any clue for extraterrestrial artifacts. His film “Disclosure Day” is scheduled to be released on June 12, 2026, and some say that he received undisclosed information from government that inspired this film. I sincerely hope to find clues that will inspire Spielberg’s next film. But most important of all, I hope that insights gained from our cosmic neighbors will inspire us to a prosperous future on Earth and in space. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

(Image credit: The Guardian)In a public lecture that I gave last night at the planetarium of the Frost Science Museum in Miami, Florida, hosted graciously by Senator René Garcia and his Deputy Chief of Staff Lauren Pardo, I emphasized that settling on nearby rocks that are less hospitable for life than Earth, like the Moon or Mars, is not the best way to secure the long-term survival of humanity. Instead, it would make more sense to launch our technological ambassadors to space in the form of AI-guided robots, or perhaps even humans, on artificial space platforms that were designed specifically for long-term survival. Nature is under no obligation to make us happy and living in the natural environment of the Moon or Mars will likely be a nightmare to all humans involved. But there is another survival mode. If surface conditions on Earth will severely deteriorate in our future as a result of a giant asteroid impact, a nuclear war or climate change, humanity might choose to go underground. Nature may have made a similar choice billions of years ago. Most of the real estate of rocky material lies far from stars. It may well be the case that most life forms in the Universe thrive underground. Astrobiologists associate the habitable zone around stars with the region where the surface temperature of a rocky planet allows for liquid water and the chemistry of life-as-we-know-it (as reviewed in my textbook “Life in the Cosmos”). However, frozen worlds far from any star may host subsurface life under a thick surface layer of ice. In 2018, I co-authored a paper (accessible here) with my former postdoc, Manasvi Lingam, which demonstrated that energy supply from radioactive materials can sustain life in liquid water underground. Some tech billionaires are already constructing luxurious bunkers to survive a societal collapse they helped create (as reported here). If we ever land a spaceship on the scorched surface a post-world-war exoplanet, we should search for billionaire bunkers with survivors. But closer to home, most life forms on present-day Mars may have indeed survived underground. It would indeed be a good idea to send helicopters with cameras into lava tubes on Mars in search for life forms which were protected there from the harsh surface conditions of extreme temperature variations between day and night, lack of liquid water and bombardment by cosmic-rays. These helicopters could also search for prehistoric paintings on the walls of natural Martian caves. If intelligent life emerged on Mars a few billion years ago, then there might even be billionaire bunkers there before Elon Musk’s arrival. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

(Image credit: NewsNation)Below is the transcript of an interview I had just before midnight last night with the anchor Jesse Weber on NewsNation (accessible in video format here). Jesse’s questions are marked with JW and my answers with AL. *** JW: Tonight, just a remarkable comment from Vice President JD Vance is putting the UFO debate back in the spotlight. So, in a recent interview, Vance was asked about the possibility of releasing more government files on UFOs, UAPs. He said, quote, we’re working on it. And then he added that he is obsessed with the topic, but it was his personal opinion on what UFOs, aliens might be that is getting the most attention. You see, Vance, who is Catholic, said he doesn’t necessarily believe these beings are from another planet. Instead, he says they could be demons. Vance says that many world religions have long acknowledged the existence of what he described as weird things out there that are difficult to explain, and that is the lens he looks through when he hears about strange encounters. Now, remember, he’s not John Smith. He’s the vice president of the United States. Does he have some inside knowledge? And remember, the comments come as the Trump administration has signaled interest in releasing more information on UFOs and UAPs. Now, no word of President Trump or any other members of the administration share Vance’s views, but how could I not talk about this? I want to bring in Avi Loeb, a theoretical physicist, the Frank B. Baird Jr. Professor of Science at Harvard University. Thank you so much. So, my first question is as follows. When I was thinking about this, the Vice President… would he have been briefed on UFOs? Could his demon theory be shaped not just by his personal beliefs, by some things he’s seen, something he’s heard? What do you think? AL: Well, thanks for having me. This is not new in the context of science and religion. We for example, now know, scientifically speaking, that the universe started in a Big Bang. We don’t know what happened before that. And that is a kind of theory that appeared in Genesis and has been the foundation for the Judeo-Christian religion in particular. And so, I don’t see necessarily a conflict between religious beliefs and science as long as everyone agrees that we should attend to the evidence. That should guide us. Let’s figure out what these things are. And my guess is that in situations where there is a lot of uncertainty, for example, if the U.S. government cannot figure out what these objects are, then, of course, people have their own speculations or theories or they connect it to some past traditional thoughts. I have no issue with that as long as everyone agrees that we should get more data and figure these things out. At the end of the day, we might recognize this as something completely unexpected but we might also figure it out. JW: I hear you right and I go back to the idea let’s say he saw heard something and it’s his interpretation of it that it has a religious context and its demons, but I think at the very least if we make this assumption in this theory. He may have saw or heard something that would suggest that whatever these beings or these phenomena are, are evil, right? That seems to be the very big narrative put out by pop culture. They’re evil, evil. Is it assumed too much that UAPs, UFOs, aliens are evil if we’re putting them in the demon context? AL: Yeah, I do think that’s going too far because I am leading the Galileo Project. We built three observatories. We are looking up at millions of objects using machine learning, artificial intelligence algorithms to figure out if there are any outliers relative to the performance envelope of human-made technologies. And my thinking about it is not in the context of demons, but more in the context of aliens. And in that case, if we are seeing any extraterrestrial technologies, the way I think of them is as the better angels of our nature. Why not be optimistic? We can learn from new technologies. We only had science and technology for a hundred years, and most stars formed billions of years before the Sun. I should also mention that the latest interstellar visitor we had, 3I/ATLAS could have potentially released some probes or objects during its path. And, in fact, there was a new report by the American Meteor Society (posted here) that there is a surge in the number of meteors on Earth over the past few months in the first quarter of 2026. We should always look up. JW: And you think that might be caused by 3I/ATLAS? AL: It’s a possibility that I discussed in an essay on Medium.com, available here. I calculated that an ejection speed of only less than a few kilometers per second, which is completely reasonable of objects, even if it was a natural iceberg that fragmented, let’s say, a year ago or a decade ago, there was a cloud of debris around it. Fragments could have hit the Earth in recent months. That’s completely reasonable in terms of the numbers. The question is whether 3I/ATLAS is technological and released some probes. That’s a completely separate question, because there you can have the fragments guided by technology. All I’m saying is we should be open-minded to the possibility that we’re not at the top of the food chain within the Milky Way galaxy, that we can learn something from siblings of our family of intelligent civilizations. And of course, you may ask: how is religion supposed to be affected by any finding? JW: Yeah. AL: So, I had a visit to Harvard University where I’m a professor by a group of theologians led by the current president of the Templeton Foundation. And they asked me, how would our religious beliefs be affected by finding extraterrestrials? And I said: “Look, I have two daughters. And when the second one was born, it didn’t take away any of the love that I have to the first one. And so, assuming that God is a parent that can attend to only one child is very limiting.” JW: Yeah, that’s a good way, that’s a really good way to try to think about that. It makes sense because if we really do get more information, that may be ways people kind of process it and accept it. Avi Loeb, thank you for taking the time. Really appreciate it. AL: Thanks for having me. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

(Image credit: Greg Wyatt)The fundamental difference between artificial intelligence (AI) and extraterrestrial intelligence (ETI) is in their training data sets. Whereas AI is trained on data limited to Earth, most of the real estate lies beyond Earth. That we fail to recognize this simple fact and focus on our immediate environment is testimony to the limitations of the human mind. Even just days before the Artemis II launch of humans to an orbit around the Moon, critics express concerns that money would be better spent on solving problems closer to home. Well, guess what … if we keep our focus only close to home, we may lose this home and everything in it to a future catastrophe. Exploration of residential areas far from home can save our descendants from extinction. Sixty-six million years ago, non-avian dinosaurs were not smart enough to avoid an asteroid impact. Are we smarter than they were or are we doomed to extinction together with our digital mirrors? (Image credit: Greg Wyatt)Earth went through many major catastrophes in the past 4.6 billion years. Its history started with the Moon-forming collision when a Mars-sized protoplanet named Theia is believed to have collided with proto-Earth. Subsequently, the Permian-Triassic Extinction, event, about 252 million years ago, eliminated about 96% of marine species and 70% of land vertebrates. Later, the Great Oxygenation Event, about 2.4 billion years ago, occurred as early bacteria began producing oxygen via photosynthesis, which was toxic to the anaerobic life that dominated the Earth at the time, leading to a massive die-off. The Earth also went through multiple snowball events during which it encountered “deep freezes” where glaciers may have reached the equator. One significant period occurred around 700 million years ago, likely triggered by changes in greenhouse gases or volcanic activity, turning the entire planet into a frozen wasteland for millions of years. The end of the Ordovician period, about 444 million years ago, was triggered by intense glaciation and falling sea levels, killing 85% of marine life. The late Devonian period, about 360 million years ago, was associated with a series of pulses over millions of years, likely caused by ocean oxygen depletion as land plants rapidly diversified. And the end of the Triassic period, about 201 million years ago, was associated with massive volcanic activity during the breakup of the supercontinent Pangaea which led to rapid climate change, allowing dinosaurs to dominate. Existential risks are inevitable also in our future. Within about a billion years all liquid water will dry up on Earth as a result of the Greenhouse effect of the brightening Sun (as discussed here), and in 7.6 billion years the drag on the expanded envelope of the Sun will deliver Earth into its hot and dense center. In the long run, the City of Jerusalem will not be within humanity’s Promised Land, because it will be consumed by the dense metallic remnant of the Sun, a white dwarf the size of Earth containing about 60% of the current mass of the Sun. The actual Promised Land for humanity’s long-term future will be on a space platform that guarantees its long-term survival. Instead of relying on a natural fusion reactor, the Sun, we could build an artificial nuclear fusion reactor inside a city-size spaceship that produces artificial gravity through rotation or rocket acceleration. (Image credit: Greg Wyatt)Our transition from the surface of a habitable natural rock to a space platform where the living conditions are manufactured technologically, is similar to the transition from the jungles of Africa where human needed to collect their food from scarce natural resources to a city where abundant food can be ordered through speech to an AI agent. Currently, our most visionary space ambitions involve traveling to other natural rocks which happen to exist in our neighborhood, like the Moon or Mars. But a more uplifting vision would be to construct a space platform that will carry humans to interstellar journeys, a Noah’s spaceship of sorts, making our survival independent of Earth’s future calamities. So far, we have not employed AI for our space missions, but future interstellar trips will likely be guided by AI, while the bodies of any human passengers will stay frozen through the boring and long parts of the journeys. We might be inspired to become an interstellar species once we discover that ETI were successful in doing so. Finding their spacecraft would guide us in selecting the technologies that made their trips successful. The fact that they arrived at our backyard before we arrived to theirs would not be surprising, given that we only had one century of modern science and technology after discovering General Relativity and Quantum Mechanics, whereas most Sun-like stars formed billions of years before the Sun. The best is yet to come. Here’s hoping that a new age of peace and prosperity will result from our encounters with ETI. Judging by the terrestrial news cycle every day, it appears likely that we are not at the top of the cosmic food chain. Recently, Vice-President JD Vance noted that Unidentified Anomalous Phenomena (UAP) might be demons flying around Earth (as reported here). If the Galileo Project will discover UAP under my leadership, I would view them instead through the words of President Abraham Lincoln as the “better angels of our nature.” (Image credit: Greg Wyatt)******* In this essay, I featured four amazing watercolors from a series created by the celebrated artist, Greg Wyatt. These watercolors incorporate inspiring statements by Giordano Bruno and Marsilio Ficino. This is the ninth in a sequence of essays, where Greg and I collaborate on the interface between art and science. The first essay in this series, titled “Music of the Cosmic Spheres,” appeared here; the second essay, titled: “Cosmic Waterfalls in Spacetime Cliffs,” appeared here; the third titled “Missing Elements in the Cosmic Jigsaw Puzzle,” appeared here; the fourth essay, titled: “Why Do We Exist?”, appeared here, and the fifth titled “Inspiration from the Stars”, appeared here, the sixth titled: “We Might Understand How the Cosmos Works Before We Understand How Life Works”, appeared here, the seventh titled “Will the Human Survive for Billions of Years”, appeared here, and the eight titled: “The Butterfly Effect of Intelligence in the Cosmos”, appeared here. *** Before my morning jog at sunrise, I received the following uplifting email: “Good morning, Avi. We have spoken over email before. I read your Medium posts and I recently watched you on Why Files — The Basement, with AJ. It was a great show! I also own a couple of your books. I believe you are right about Aliens, Alien probes and life on other planets, other than our own. The reason I believe that is because every time I consider any single problem that seems absolutely impossible to resolve, I just look up at the stars at night and I think, “it’s impossibe that Avi is wrong, hard data or not, I believe in my heart that he is correct.” Space goes on forever but on the other hand how can it? Where is the end? Is there a wall? What is on the other side of that wall then? If there’s a wall, then what is containing the wall? If there is no wall, how will you ever reach the end? For this reason alone, I believe that the conclusion is so likely and so undeniable, that people are crazy not to understand that. I do not think you are wasting your time. I think you are doing immense work for the good of humanity and for our continued existence in the universe. I look forward to reading the results of your future work and people such as myself will always, always, believe in you, no matter what the critics say. It’s just common sense. Robin Lindberg” ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

An artist’s illustration of the collision of the protoplanet Theia with Earth (left) that led to the formation of the Moon. (Image credit: Hernán Cañellas)A giant impact of a Mars-size proto-planet named Theia with proto-Earth, 4.5 billion years ago, may have ejected debris that coalesced to form our Moon. Computer simulations support this giant impact hypothesis, as discussed here. Could a moon form through a similar process when two neutron stars collide? Dense star clusters, known as globular clusters, contain of order a million stars and are known to have stellar remnants segregated near their centers. These remnants include stellar-mass black holes and neutron stars. They are typically more massive than the background stars and hence settle towards the cluster center through a gravitational segregation process resembling the separation of heavy dust particles from air molecules under the influence of the Earth’s gravity. Near the cluster center these remnants find each other, creating pairs of black holes that coalesce through the emission of gravitational waves. This natural process could explain the origin of many of the gravitational wave sources detected by the LIGO-Virgo-KAGRA (LVK) collaboration over the past decade, as originally proposed here. The cores of globular clusters are known to contain an abundant population of neutron stars which appear as pulsars or X-ray sources with a mass of up to twice the mass of the Sun (as discussed recently here). These neutron stars, remnants from core collapse of massive stars, have a mass density of an atomic nucleus and a characteristic size of a city, about 12 kilometers (as discussed here). The dense core of a globular cluster can lead to the formation of pairs of black holes or neutron stars but also to three-body systems that are dynamically unstable, and can result in a head-on collision between two neutron stars under rare circumstances (as discussed here). When two neutron stars collide head-on, their merger is expected to lead to a black hole carrying most of their combined masses. However, just as in the collision between Thea and Earth, a fraction of the mass might be ejected as debris that coalesces to form a moon made of neutron star matter. Equilibrium configurations of stable neutron stars exist down to 0.09 of the mass of the Sun (as discussed here). Therefore, the debris from a head-on collision between two neutron stars could potentially lead to the formation of a central black hole or neutron star accompanied by a low-mass neutron-star moon. As a result of the emission of gravitational waves, the moon will ultimately merge with the central object. The lifetime of the system depends on the initial separation of the moon from the central object as well as their masses. An alternative channel for creating a black hole moon is from the core collapse of a single progenitor star to a black hole and a debris disk that coalesces into a neutron star moon, as discussed here. On November 12, 2025, the LVK collaboration reported the detection of a gravitational wave signal from a compact merger candidate named S251112cm (as reported here). This event is statistically compelling due to its relatively low False Alarm Rate, estimated at about 1 per 6.2 years (as noted here). The source luminosity distance is estimated to be in the local Universe, measuring about 300 million light years (93 ± 27 Mpc), but a search for an electromagnetic counterpart did not yield a detection (as reported here). The analysis of the gravitational wave signal implies that the source chirp mass falls predominantly in the range of 0.1 to 0.87 solar masses, implying a sub-solar mass object at the 99% confidence. The more massive object could be in the range of 1–3.5 solar masses, based on Figure 1 here. The inference of a low-mass object raises the possibility that S251112cm may have been produced by the coalescence of a neutron star moon and an order of magnitude more massive companion in the form of a black hole or a neutron star. Our own Moon might also crash back on Earth. This would not be the result of gravitational wave emission but rather its drag on the envelope of the Sun once it expands as a red giant to engulf the Earth-Moon system (as discussed here). Some moons are doomed to crash back on their birth place, just like adults settling back to their childhood home. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

Recently, Earth arrived closest to the path of 3I/ATLAS through the Solar System. This 3D visualization shows the anti-clockwise orbit of Earth (and other planets) around the Sun, with positions marked for March 27, 2026. The past trajectory of 3I/ATLAS is shown in gray, including its elevation from the Earth’s ecliptic plane.In the second half of March 2026, Earth arrived within its closest distance of 54.6 million kilometers from the path of the interstellar object 3I/ATLAS through the Solar System. By now, 3I/ATLAS is heading out of the Solar System at a distance of 5.3 times the Sun’s distance from Earth. Back on August 8–12, 2025, data the SPHEREx space observatory revealed a carbon-dioxide gas plume extending out to a distance of at least 348,000 kilometers from the nucleus of 3I/ATLAS (as reported in the caption of Figure 2 here). In case this gas cloud around 3I/ATLAS was accompanied by solid fragments of debris from 3I/ATLAS, some of these fragments could have collided in recent months with Earth. Let us work some numbers that could educate us whether such collisions are possible. The ejection speed required for a fragment to cross a distance of 54.6 million kilometers in the seven months that elapsed since August 2025 is 3 kilometers per second. This is just 5% of the speed of 3I/ATLAS through the Solar System, which is about 60 kilometers per second. But if these fragments departed from 3I/ATLAS ten years ago, when the interstellar object was located at a distance of 126 times the Earth-Sun separation, the required ejection speed would have been only 170 meters per second, comparable to the thermal speed of the gas molecules surrounding it. This implies that if 3I/ATLAS shed solid fragments from its surface a long time ago, some of these fragments could have potentially impacted Earth in recent months. In a recent paper that I co-authored with Valentin Thos and Andi Burkert (accessible here), the mass of 3I/ATLAS was estimated, based on its non-gravitational acceleration, to be of order a billion metric tons. Assuming that a tenth of this mass was broken into fragment of centimeter-radius, a total of ten trillion fragments — each carrying a mass of 10 grams, were shed by 3I/ATLAS. The maximum fraction of these fragments that could intercept the Earth equals to the ratio of the cross-sectional area of the Earth divided by the surface area of a sphere with a radius of 54.6 million kilometers. This gives a total maximum of 34,000 fragments that would burn up as a result of their passage through the Earth’s atmosphere and appear as meteor fireballs in the sky. The expected surge in the number of meteor fireballs scales in proportion to the fraction of the mass of 3I/ATLAS carried by the fragments (assumed to be 10% in the above estimate) and inversely with the fragment mass (assumed to be 10 grams above) or the square of the distance that the fragments traveled before hitting Earth (assumed to be 54.6 million kilometers above). Adopting more pessimistic values of a mass fraction of 1% and a distance similar to the Earth-Sun separation (150 million kilometers) still yields 30 extra fireballs triggered by meteoroids, each measuring 5 centimeter (2-inches) in diameter. But even in the most optimistic scenario, where half the mass of 3I/ATLAS was lost to fragments, no excess meteoroids larger than a meter in diameter or a ton in mass, are expected. There is not enough mass available in 3I/ATLAS to create a sufficient number fragments so massive that one of them will intercept the Earth. On March 21, 2026 at 4:40PM CT, a 1-ton meteoroid broke apart above the Houston metro area, producing loud boom and a 26-ton TNT equivalent airburst (as reported here). On March 17, 2026 at 8:57 AM ET, a 7-ton meteoroid exploded over Lake Erie, producing a boom and a 250-tons TNT equivalent airburst across Ohio and into Pennsylvania (as reported here). These recent fireballs are too energetic to be associated with 3I/ATLAS. Nevertheless, there appears to be a surge in the number of smaller meteor fireballs during the first quarter of 2026. A report this week by the American Meteor Society (posted here) documented an increase by a factor of a few in the number of bright events witnessed by more than 200 people. Almost half of all March 2026 events were each seen by more than 50 people. The March 2026 average witness count per event was 142.7 — nearly three times the next-highest March on record (49.4 in 2021). A systematic study of the directional and velocity information for the 2026 meteoroids of different sizes could assess which any subset of them might have properties consistent with past ejections of fragments by 3I/ATLAS towards Earth. If the timing, arrival direction and speed of any them are consistent with an ejection from 3I/ATLAS, then finding related meteorites on the ground would be revealing about the nature and origin of 3I/ATLAS. *** Yesterday, NASA announced here that there is no reason to get excited because the recent surge in meteor fireballs is simply associated with the fireball season. On a separate note, a NASA representative argued that a cone-shaped object on Mars is a rock that was naturally formed from Martian winds. When asked by a New York Post reporter about this assessment, I replied: “The conical object was observed by different cameras on the Curiosity rover and viewed from different angles, as discussed in my essay, posted at: https://avi-loeb.medium.com/is-the-mysterious-cylinder-on-mars-photographed-in-2022-by-the-curiosity-rover-a-human-made-6fcd8e242fea The Curiosity image clearly shows that no rock resembles this object within its natural environment. In addition, a rock is not expected to have a smooth cylindrical surface with a flat end. If this object is a rock, we should see other examples of it. I challenge the NASA representative to show us another example of a rock that resembles this object in any of the Curiosity rover images. It is ironic that NASA named its rover Curiosity whereas NASA representatives lack any sense of curiosity about this anomalous object. By sweeping anomalies under the carpet of traditional thinking, we miss opportunities for discovering something new.” Drawing titled: “Cosmic Thoughts of Avi Loeb” by Azadeh. It arrived with the following message: “Dear Dr. Loeb, I wanted to take a moment to express my appreciation for your work. Your combination of scientific rigor, intellectual generosity, and genuine humility is rare and deeply inspiring for those of us following your research from the sidelines. Thank you for the example you set in how curiosity and humility can coexist at the highest levels of science. It genuinely means a lot. With respect, Azadeh”ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

(Image credit: Futurism)Interstellar objects are identified by their positive energy relative to the Sun. This is not a metaphor but rather a physical characteristic, formulated as: E > 0. It means that interstellar objects move faster than the escape speed from the Solar System, which is dominated by the Sun’s gravity. Far from the Sun, their energy is purely in the form of kinetic energy (per unit mass): E = (1/2) U² where U is their velocity in interstellar space. Since energy is conserved under the Sun’s gravity, their local velocity v evolves as a function of their changing distance r from the Sun according to the relation: E = -GM/r + (1/2) v² Altogether, in the presence of gravity: v² = U² + 2GM/r The local escape speed v_e at a distance r from the Sun is defined as the value of v for U=0, namely: v_e² = 2GM/r The Solar escape speed v_e represents the minimum speed needed to carry an object out of the Solar System. Any object observed moving faster than v_e at a heliocentric distance r is flagged as interstellar in origin. At the orbital radius of Earth, the escape speed is 42.1 kilometers per second. However, the situation changes under the action of a non-gravitational force, such as the rocket effect from outgassing. Let us restrict our attention to the simple case of a non-gravitational acceleration, A[r], that scales similarly to gravity as 1/r² (as was the case for 1I/`Oumuamua or 3I/ATLAS) and always points opposite to the object’s velocity, namely away from the Sun before perihelion. In this case, the energy E of the interstellar object will be reduced by A*r as the object arrives from interstellar space to a distance r from the Sun. The reduction in energy results from the fact that this non-gravitational acceleration allows down the object and reduces its positive kinetic energy. The effect is equivalent to pumping the breaks on a vehicle. If the energy change exceeds the positive value E that the interstellar object possessed to start with, then the net energy value will turn negative and the object will become gravitationally bound to the Sun. The condition for an interstellar object to be trapped by the Sun owing to its non-gravitational acceleration is A*r > (1/2) U², or equivalently: A > U²/2r This can be compared to the gravitational acceleration at a distance r from the Sun, g=(GM/r²) = (v_e^/2r). The above requirement for trapping an interstellar object in the Solar System is therefore: A/g > (U/v_e)² Sublimation of ice by sunlight typically results in outgassing limited by the thermal speed of a few hundred meters per second, which is a hundred times slower than v_e at the Earth-Sun separation. This means that the resulting non-gravitational acceleration of natural icebergs near Earth can only reach values as small as: A/g < (0.01)²=0.0001. *** Consider the example of the interstellar object 3I/ATLAS which entered the Solar System with an interstellar speed of U = 58 kilometers per second. The escape speed at its perihelion distance of 1.36 times the Earth-Sun separation is v_e = 36 kilometers per second. In order for 3I/ATLAS to slow down enough and stay in the Solar System, the object had to break with a non-gravitational acceleration that is larger than the gravitational acceleration by a factor of A/g > (58/36)² = 2.6 The actual non-gravitational acceleration that was measured for 3I/ATLAS, as discussed in the recent paper I co-authored with Valentin Thoss and Andi Burkert here, is merely: A/g ~ 0.0001 Clearly, 3I/ATLAS did not slow down at the level needed for it to stay in the Solar System. The required threshold for staying of A/g > 2.6 applies to any fragments released by 3I/ATLAS, since the acceleration condition for any object to stay in the Solar System does not depend on the object’s mass. *** Today, the NSF-DOE Rubin Observatory released its data preview here. The full Rubin database over the coming decade is expected to reveal dozens of new interstellar objects. If any of them appears to slow down enough to become gravitational bound to the Solar System, this breaking should be regarded as a strong enough technological signature to elevate its rank close to 10 on the Loeb Classification Scale of interstellar objects (as discussed here, here and here). ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

Predicted evolution of the local group of galaxies over the next 10 billion years. Panels (a) and (b) show 100 randomly selected tracks from 10,000 realizations for the future trajectories of the Milky-Way (MW) and Andromeda (M31) galaxies, and panels © and (d) show the same, including the minor galaxies M33 and the Large Magellanic cloud (LMC). In both cases, the left panel is the face-on projection and the right panel is the edge-on projection with respect to the orbital plane of the Milky-Way and Andromeda centers. The green and red lines trace the orbits of the Milky-Way and Andromeda, while the pink and silver lines trace the Large Magellanic Cloud and M33, respectively. Line brightness indicates the relative probability density at any position. (Image credit: H. Wu et al. 2026)The nearest neighbor of our own Milky-Way galaxy is the Andromeda galaxy, located at a distance of 2.5 million light years. The dark matter halos of the two galaxies, containing about a trillion solar masses each, are currently touching each other as the two galaxy cores are headed towards each other on a collision course. Alien astronomers in Andromeda might use their own telescopes to monitor the encounter. A communication signal from them will require 2.5 million years to reach us, comparable to the duration of the entire human history on planet Earth. A merger of these similar galaxies will scramble their stellar disks into a giant elliptical galaxy. I dubbed this merger product “Milkomeda” in a paper (accessible here) that I wrote with my former postdoc T.J. Cox in 2007. Stars within the two galaxies, including the Sun, will not physically collide with each other because of the vast space that separates them. Our computer simulation indicated that during the merger process, the Sun might be carried along with a group of other stars trailing the Milky-Way core. During this period, a terrestrial astronomer would be able to see the Milky-Way and Andromeda from a distance as their stars fill the night sky in evolving patterns. Within 5 billion years, while the Sun is still alive — as its remaining life span is 7.6 billion years, Milkomeda will acquire twice the stellar and dark-matter reservoirs of the Milky Way. Given that the rest of the Universe is accelerating, within a hundred billion years from now Milkomeda will be surrounded by vacuum in a dark and lonely cosmic environment. The merger between the Milky-Way and Andromeda will constitute the last major event in our cosmic history book, followed by a dull and dark future after that. We might still be able to infer that the universe expands by observing hypervelocity stars ejected by Milkomeda, as I pointed out in a paper published here. This is the only publication in my resume that has a chance of being cited in a trillion years. Currently, the Milky-Way and Andromeda (also called M31) are falling toward each other at a speed of 110 kilometers per second. However, a paper published here in 2024 argued that the merger is not guaranteed, given the gravitational influence of other galaxies in between them — such as M33 and the Large Magellanic Cloud (LMC). Whereas including M33 increases the merger probability, the orbit of the Large Magellanic Cloud runs perpendicular to the Milky Way — Andromeda orbit and makes their merger less likely. The authors argued that uncertainties in the present positions, motions, and masses of all galaxies allow for a 50% chance that that there will be no merger between the Milky-Way and Andromeda during the next 10 billion years. Time evolution of the separation between the Milky-Way and Andromeda centers for 100 representative tracks and a merger fraction of 90% within 10 billion years, computed from 10,000 trajectory samples. White symbols along the bottom mark the corresponding merger times, and the white curve shows the most probable evolution. (Image credit: H. Wu et al. 2026)Today, a new numerical study (accessible here) used the latest and most precise Gaia-based proper motions for stars in Andromeda to show that the merger probability rises to 90%, with a median merger time of 6.5 (+1.3/−1.5) Gyr, broadly restoring the classical view expressed in the paper that I co-authored with T.J. Cox. Future proper-motion measurements with uncertainties below 2 micro-arcseconds per year will be required to firm-up this conclusion in anticipation of the merger. Of course, the alternative route for figuring out the expected fate of the Milky-Way is to seek electromagnetic signals from alien astronomers in Andromeda. If they developed telescopes with uncertainties below 2 micro-arcseconds per year a few million years ago, they may have already beamed their answer towards us — announcing what to expect in our mutual party. When they arrive to the vicinity of the Sun, hopefully in 5 billion years, we can all meet and celebrate the event together. Salute! 🥂 ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

Deuterium to hydrogen (D/H) ratios in methane (CH4) and other molecules within the solar system and beyond. (Image credit: N. Roth et al. 2026)Hydrogen is the most abundant element in the Universe, composed of an electron and a proton. Deuterium includes a neutron in addition to that proton in its nucleus. In the first twenty minutes after the hot Big Bang, a primordial abundance of one deuterium atom per 40,000 hydrogen was generated. This abundance ratio is similar to the value found in the Sun or Jupiter. Earth has a higher abundance, with about one for every 6,500 hydrogen atoms in seawater being deuterium. Deuterium can be extracted from seawater inexpensively, making it an abundant fusion fuel that could power human needs for millions of years. In 1942, during early discussions for the Manhattan Project, Edward Teller asked whether the extreme temperatures of a fission atomic bomb explosion could cause deuterium in the oceans to undergo fusion and burn our planet. This hypothesized chain reaction was shown to be extremely unlikely by Hans Bethe who calculated that radiative energy losses would far exceed any energy gained from fusion, causing any such reaction to fizzle out. Deuterium acts as a primary fuel source for nuclear fusion due to its high energy yield and relative ease of reaction. In fusion experiments, deuterium is commonly used in a mixture with tritium (with two neutrons in addition to the proton in its nucleus), a combination that ignites at the lowest possible temperature compared to other fusion fuels. The fusion of a deuterium nucleus with a tritium nucleus creates a helium-4 nucleus and a high-energy neutron. What is the deuterium abundance in the interstellar object 3I/ATLAS? Recently, two new papers used spectroscopic data from the Webb telescope to deduce exceedingly high fraction of deuterium in two molecules shed by 3I/ATLAS. They found one deuterium in 100 hydrogen atoms in water (H2O) and one deuterium in 30 hydrogen atoms in the organic molecule of methane (CH4) around 3I/ATLAS. Isotopic ratios observed in water (H2O) shed by 3I/ATLAS compared with Galactic and Solar System observations for D/H (top) and 12C/13C (bottom). (Image credit: M. Cordiner et al. 2026)The first paper on March 6, 2026 (available here) analyzed spectroscopic data on water in the gas plume around 3I/ATLAS, and derived an enrichment at a level of D/H = (0.95 ± 0.06)%, which is more than an order of magnitude higher than all known comets. In addition, the 12C/13C ratios (141–191 for CO2 and 123–172 for CO) was reported to exceed typical values found in the Solar System and nearby interstellar clouds and protoplanetary disks. Today, March 24, 2026, a new paper (available here) reported an unexpectedly high D/H = (3.31 ± 0.34)% for the organic molecule of methane (CH4) shed by 3I/ATLAS. This abundance is three orders of magnitude higher than found in methane on solar system planets and well above the values in comets or meteorites. In particular, it is a factor of 14 higher than the value measured in comet 67P/Churyumov-Gerasimenko by the Rosetta spacecraft. The authors of both papers suggest that the extremely high D/H ratios of water and methane in 3I/ATLAS are a natural consequence of formation in a cold environment below 30 degrees Kelvin, within a protoplanetary disk about 10–12 billion years ago. However, as I showed in a recent paper here, the association of 3I/ATLAS with the rare population of old metal-poor stars is untenable because they do not carry a large enough reservoir of heavy elements. It should also be kept in mind that ancient proto-planetary disks could not have been cooler than the cosmic microwave background at the time they formed, which at a redshift of ~10 had a temperature of 30 degrees Kelvin. Hence, an important question arises: since deuterium is fusion fuel, might its over-abundance in 3I/ATLAS flag a technological signature? ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

The so-called Hertzsprung–Russell diagram of 23,000 stars from the Hipparcos and Gliese catalogues, shows stellar luminosity versus color ranging from hot blue-white stars on the left side to cooler red stars on the right side. Hydrogen-burning stars like the Sun populate a band running from top-left to bottom-right called the Main Sequence. Giant stars clump on the upper-right side. At the lower-left is the band of white dwarfs, the dead cores of old stars that cool slowly over billions of years towards the bottom-right. (Image credit: Wikimedia)In my previous essay, posted here, I suggested that to preserve the habitability of its home planet — an advanced technological civilization might choose to move the planet away from a brightening sun-like star. The preferred planet-star separation would scale as the square root of the evolving star’s luminosity. If this idea happens to be popular among our siblings in the family of intelligent civilizations within the Milky-Way galaxy, it might lead to an over-abundance of Earth-mass planets in the habitable zone around old Sun-like stars, as these stars evolve along the red giant branch of their Hertzsprung-Russel diagram. But as the host sun-like star eventually turns to a faint white dwarf, the resident civilization might choose to migrate its planet closer to the dimmed furnace. This would imply an artificial over-abundance of habitable Earth-like planets around white dwarfs. The graveyard of the Milky-Way galaxy is full of billions of corpses of dead sun-like stars in the form of old white dwarfs, each carrying about 60% of the mass of the Sun. At their typical age of a few billion years, the surface temperature of these white dwarfs is similar to that of the Sun, about 6,000 degrees Kelvin, resulting in white light which is conducive for life-as-we-know-it. The size of a white dwarf is comparable to that of Earth, but the habitable zone around it, is a hundred times bigger — amounting to 1 to 3 times that current radius of the Sun. Closer than a solar radius, the gravitational tide from the white dwarf would destroy a rocky planet. The fact that the size of the white dwarf is comparable to that of Earth makes transits easy to detect. The probability for a transit is of order 0.6% for a habitable Earth-like planet around a white dwarf. This offers a unique opportunity for probing the composition of the atmospheres of habitable-zone Earth-mass exoplanets that transit white dwarfs. In 2013, I co-authored a paper with Dani Maoz (published here) which showed that during a transit by an Earth-mass planet across a white dwarf, the transmission spectrum of the planet’s atmosphere would show prominent bio-markers such as molecular oxygen absorption at a wavelength of ∼ 0.76 micrometers. We calculated that a potentially life-sustaining Earth-like planet transiting a white dwarf would be detectable by the Webb telescope in about 5 hours of total exposure time, integrated over 160 two-minute transits. A follow-up paper that I co-authored in 2014 here with my then undergraduate student Henry Lin (currently a professor at Princeton University), showed that industrial pollution is also detectable in habitable Earth-like planets around a white dwarf. In particular, tetrafluoromethane (CF4) and trichlorofluoromethane (CCl3F) are the easiest to detect chlorofluorocarbons (CFCs) resulting from technological activity. Our paper estimated that a few days of total integration time on the Webb telescope will be necessary to detect the concentration of CCl3F or CF4 for industrial pollution that is ten times higher than the current level on Earth. The discovery of an over-abundance of habitable Earth-like planets around red giants or white dwarfs can be substantiated as a technological signature by finding industrial pollution in the related planetary atmospheres. Finding such evidence would provide a useful guide to humanity on how to survive on Earth in the next 10 billion years, both before and after the Sun will turn into a red giant and then a white dwarf in 7.6 billion years (as calculated here). Based on the census of white dwarfs reported here, most stars formed billions of years before the Sun. Given that we arrived late to the cosmic party, we might have missed numerous tragic incidents involving the extinction of civilizations which did not engage in a cosmic engineering project to save their planet before it lost habitability. We were not around to hear their cry for help. We better be wise to learn the lessons from the surviving civilization by studying habitable planets around red giants and white dwarfs. As the philosopher George Santayana stated in his 1905 book titled The Life of Reason: Reason in Common Sense: “Those who cannot remember the past are condemned to repeat it.” ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

(Image credit: Greg Wyatt)The butterfly effect is a concept in the theory of chaos describing how tiny, initial changes in a complex system can result in massive, consequences. The metaphor coined by Edward Lorenz in the 1960s, suggests that a butterfly flapping its wings in Brazil could, through a chain reaction, trigger a tornado in Texas, highlighting extreme sensitivity to initial conditions. A butterfly is a minor mover drawn from the natural world. But for an intelligent technological civilization with major computational resources, could “flap its wings” in a deliberate fashion so as to accomplish a major goal. The related effect could serve as a technological signature of intelligence in the cosmos, one of many that I discussed in a new podcast interview of the “The Basement/The Why Files”, available at the following link: https://medium.com/media/0c772e2d60337ed4f21bb7c8b1a8f9ca/href(Image credit: Greg Wyatt)In particular, consider our future in which the Sun will inevitably brighten up and boil off all liquid water on Earth’s surface, turning it into a desert within a billion years through the greenhouse effect, as predicted here. To avoid this doomsdays scenario and keep the Earth habitable, our descendants might embark on a cosmic engineering project which will aim to grow the orbital distance of the Earth from the Sun at the necessary rate. This task can be accomplished by tugging the Earth gravitationally by another body which orbits the Sun and resonates intermittently with the orbits of the Earth and Jupiter. Each time the currier body flies past Jupiter, it may “steal” a tiny amount of orbital energy through a gravity assist. As this “butterfly” then returns to the proximity of Earth, it can “donate” that energy during a close flyby, nudging Earth’s orbit slightly outward. This scheme relies on gravity assists and orbital resonances to transfer energy from a massive outer planet, like Jupiter, to Earth. By timing these flybys to be resonant and always transfer energy with the same sign, the effect can be amplified over hundreds of millions of years — much like pushing a child on a swing at just the right moment to increase its height. This cosmic engineering project to save humanity could involve selecting and equipping suitable Asteroid or Kuiper Belt objects with technological engines so that they will serve as the required “butterflies,” swinging periodically by the Earth and then Jupiter. This could raise the orbit of Earth significantly, but only lower Jupiter’s orbit by a tiny amount, since Jupiter is 318 times more massive than Earth. (Image credit: Greg Wyatt)The mass of these “butterflies” can be chosen so as to expand the Earth’s orbit by just the right amount over a billion years to maintain a constant solar flux on Earth’s surface over that period. This would mean tailoring the Earth-Sun separation to scale as the square root of the solar luminosity. Searching for such a scaling among habitable planets around other stars can be used to detect the signature of advanced technological civilizations which chose to engage in similar cosmic engineering projects. If this idea was popular among our siblings in the family of intelligent civilizations within the Milky-Way galaxy, then it would result an overabundance of Earth-mass planets in the habitable zone around old Sun-like stars as these stars evolve along the red giant branch of the Hertzsprung-Russel diagram — an inevitable consequence of the natural evolution of these nuclear fusion furnaces. (Image credit: Greg Wyatt)*** Cosmic engineering projects might not be restricted to planetary systems. Given the accelerated expansion of the Universe, intelligent civilizations which were used to communicating with each other across cosmological distances might have decided to propel themselves closer together so that they would not be pulled apart and lose contact with each other in the distant future due to the accelerated expansion. Could we identify the related motions or artificial clustering of sources in cosmological data sets? I showed As in a paper here that the power required to move a star at a constant speed across cosmological distances can be supplied by the nuclear energy production in the star. Assuming that a significant fraction of this power is emitted in the infrared, the Webb Telescope will be able to detect a single stellar-mass object propelled at a constant speed out to a distance of about 30 million light years times the speed in units of 10,000 kilometers per second. Discovering the non-gravitational clustering and dynamics of many such sources would provide evidence for a new phenomenon of cosmic engineering on large scales. *** This paper was inspired by an email exchange that I had with Freeman Dyson (as documented here). Back then, I published a paper here which calculated that in a trillion years from now, all extragalactic light sources will cease to be visible due to the accelerating expansion of the universe. Future astronomers would therefore be stuck looking only within their own galaxy. Not only would the absence of extragalactic sources make for a lonely universe, but it would deprive future astronomers of the tools that we have used to arrive at our current understanding of cosmology, such as extragalactic supernovae and the cosmic microwave background (CMB) radiation. Despite this, I suggested an observational signature by which these astronomers could still derive the standard cosmological model: hypervelocity stars. In our correspondence, Freeman as the “ultimate optimist” suggested a means by which future civilizations could avoid this fate. He proposed that a civilization could harness the gravitational energy of a group of galaxies in some way as to pull together colossal collections of galaxies before they were thrown apart from each other by cosmological expansion. Two years before I was born — in 1960, Freeman conceived here of civilization-scale engineering project, currently labeled as a Dyson Sphere, a megastructure which intends to harvest much of the energy output of a star by its resident civilization. In our correspondence, Freeman suggested searching for anomalous clustering of galaxies to detect such “cosmic engineering.” In response, I mentioned two possible observational signatures of cosmic engineering: redshift surveys and the Sachs-Wolfe effect. Redshift surveys use galaxies to trace the distribution of matter on large scales throughout the Universe. By the Sachs-Wolfe effect, if some advanced civilization pulled together an cluster of galaxies far bigger than “normal” superclusters, then we could detect it from the energy lost by CMB photons as they climb out of the cluster’s enormous gravitational potential well. Signatures of anomalous clustering are not actually observed in either type of surveys, but Freeman noted that given the trillion-year timescale of the problem, “we have plenty of time to start doing it ourselves.” Below is the full scope of our email correspondence in 2011. Avi Loeb: Dear Freeman, In 2002 I wrote a paper about the long-term future of our Universe (Phys. Rev. D65, 047301, 2002). Back then, you asked me in an e-mail to let you know if I have any interesting follow-up thoughts on the subject. Attached is a short paper that I had just submitted for publication on the same subject. I would love to hear any comments you might have about it. With best wishes, Avi Freeman Dyson: Dear Avi, Thank you for sending the paper. I found nothing wrong with it. It presents a dismal picture of the future awaiting our descendants. Since I am an incurable optimist, I raise the question, how much this future could be changed by a large-scale intervention of intelligent life. A very rough estimate indicates that large-scale “cosmic engineering” could be feasible. Using available gravitational energy as the motive power, roughly ten percent of the mass from one percent of the observable universe could be collected within a volume small enough to remain permanently bound together gravitationally. The collection could be done in a single Hubble time and could then be maintained with small active adjustments. So, our descendants would stay in communication with a hundred million galaxies instead of only one. It is also possible that some of our more advanced colleagues elsewhere in the universe already began this process. We should look out for evidence of large-scale coordination of gamma-ray bursts or other phenomena indicating high velocity movement of large masses. It would be interesting to examine such possibilities in detail. Thank you for the suggestion. Yours ever, Freeman Dyson. Avi Loeb: Freeman, Your underlying assumption is that intelligent beings prefer as much company as possible. I can only say that as I get older, I prefer to stay away from other people as much as possible, since I have the feeling that I heard it all. Extrapolating to the distant future, I am entirely complacent with us being surrounded by vacuum and protected by an event horizon. Aside from the benefit of not having any distractions, this will reduce the risk of a hostile invasion by another civilization. Yours, Avi Freeman Dyson: Each to his own taste. History without hostile invasions would be very boring. FD. Avi Loeb: Putting prejudice aside, we already have relevant data for testing your proposition about “cosmic engineering” on very large scales. SDSS provided us with a map of the distribution of galaxies out to a redshift of z=0.3 (and SDSS III is now reaching farther out). The biggest bound systems in the survey are clusters of galaxies, containing at most ~10^{15} solar masses or ~1000 galaxies each. The existence of clusters is fully consistent with the initial conditions we detect in the microwave background at redshift z=1000. Since the initial conditions are Gaussian, it should be easy to identify “cosmic engineering” in the form of a rare over-dense region (supercluster) containing many more than ~1000 galaxies. A region compact enough to bind a million galaxies against cosmic acceleration would have imprinted an anomalously large Sachs-Wolfe effect on the microwave background or would have induced unusually high peculiar velocities. We do not see anomalies of this magnitude. The biggest supercluster in our vicinity is the Shapley supercluster, but it is expected to be dissolved in the future by the cosmic acceleration according to the calculation in Munoz, J, & Loeb, A. “The Density Contrast of the Shapley Supercluster”, MNRAS, 391, 1341 Of course, it is possible that the Shapley supercluster is still “under construction”, or that “cosmic engineering” operates on much smaller scales. Avi Freeman Dyson: That is disappointing. On the other hand, if our colleagues have been too lazy to do the job, we have plenty of time to start doing it ourselves. FD. ******* In this essay, I featured four amazing watercolors from a series created by the celebrated artist, Greg Wyatt. These watercolors incorporate inspiring statements by Giordano Bruno and Marsilio Ficino. This is the eighth in a sequence of essays, where Greg and I collaborate on the interface between art and science. The first essay in this series, titled “Music of the Cosmic Spheres,” appeared here; the second essay, titled: “Cosmic Waterfalls in Spacetime Cliffs,” appeared here; the third titled “Missing Elements in the Cosmic Jigsaw Puzzle,” appeared here; the fourth essay, titled: “Why Do We Exist?”, appeared here, and the fifth titled “Inspiration from the Stars”, appeared here, the sixth titled: “We Might Understand How the Cosmos Works Before We Understand How Life Works”, appeared here, and the seventh titled “Will the Human Survive for Billions of Years”, appeared here. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

Stars in the dwarf galaxy Pictor II, which is more than 10 billion years old. The right panel shows a close-up of the star PicII-503, with the lowest iron content ever measured outside of the Milky-Way disk of stars. (Image credit: CTIO/NOIRLab/DOE/NSF/AURA)One of the remarkable insights in the biblical story of genesis is that the observable Universe had a beginning in time, akin to the modern notion of a Big Bang. This idea was not philosophically appealing to scientists like Albert Einstein, who in 1917 added a cosmological constant to his equations of General Relativity, in order to counteract the gravitational attraction of matter and radiation and allow for a static eternal Universe. He later realized that such a delicate balance is unstable and leads to a clumpy Universe. Indeed, today cosmologists explain the emergence of galaxies like the Milky-Way as a natural consequence of gravitational instability in an expanding Universe which contains a cosmological constant. How can we infer the current age of the Universe? Locally, we find that the Universe is expanding with the recession speed of distant galaxies being proportional to their distance. The proportionality factor, called the Hubble constant after the astronomer Edwin Hubble, is the ratio between the recession velocity and distance. The time that elapsed since these galaxies overlapped equals to their distance divided by their velocity. Crudely speaking, this would imply that the age of the Universe is simply the inverse of the Hubble constant. For the current value of Hubble constant, about 70 kilometers per second per megaparsec, its inverse is 14 billion years. The value of the Hubble constant is still uncertain, as different techniques for distances measurements provide values that are discrepant by +/-5%, as summarized here. This ambiguity amounts to an age uncertainty of 0.7 billion years. A more refined approach is to trace the distance that light travelled since the beginning by studying the Cosmic Microwave Background (CMB), the relic radiation from the Big Bang. The Universe became transparent to the CMB as soon as the cosmic temperature cooled under 4000 degrees Kelvin, allowing electrons to join protons in making hydrogen atoms. This removed the fog associated with electron scattering of the CMB at about 400,000 years after the beginning. The distance that sound waves propagated during that time defines a yardstick for the characteristic CMB brightness patterns. The angle that it occupies in the sky depends on the distance travelled by the CMB since that time which — given the speed of light — reflects the age of the Universe. The acoustic patterns can also be found in the large-scale distribution of matter, as traced by galaxies at recent cosmic times. This approach yields a cosmic age of about 13.8 billion years. The Sun formed in the last third of cosmic history, 4.6 billion years ago, and our modern technological era is only a century old. We arrived late to the cosmic party. Most stars formed before the Sun. This offers a second path for measuring the age of the Universe. No star can be older than the Universe for a simple reason. As we go back in time before the first minute after the Big Bang, the cosmic density of matter and radiation was much higher than that found in the interior of stars. No star could have not survived these extreme conditions in the infant Universe. Cosmic archaeology can therefore set a lower limit on the age of the Universe by finding ancient stars that formed in the first hundreds of millions of years after the Big Bang. Recent data from the Dark Energy Camera (DECam) mounted atop the Víctor M. Blanco 4-meter Telescope in Chile, revealed stars inside the nearby dwarf galaxy Pictor II at a distance of 150,000 light years. This satellite galaxy of the Milky-Way is more than 10 billion years old. One of the oldest of these stars is PicII-503, with only a part in 43,000 of the iron mass-fraction of the Sun, as reported last week here. Another path for cosmic archaeology involves studies of the materials carried by interstellar objects, born out of the debris of distant stars. They also cannot be older than the Universe. The age of interstellar objects can be inferred by isotope dating. Remarkably, the measurement of deuterium to hydrogen and 12C/13C ratios, as reported here and here last week, implies that the age of the interstellar object 3I/ATLAS is 10–12 billion years, suggesting that it may have formed in the early Universe. As I discussed here, this raises a puzzle regarding the mass reservoir of its parent star population. *** Jeanne Calment of France is the oldest verified person to have ever lived. She died in 1997 at an age of 122.45 years. This is a hundred million times shorter than the age of the Universe. One would expect the fact that we live for less than 0.00000001 of cosmic history to sink in and make us humble. But not so. We prefer to ignore it. Even though our life is brief, we choose to invest most of it in conflicts with each other. Out there in the sky, there is a giant cosmic message telling us how insignificant we are. And yet, even mainstream astronomers who adopt the job of looking up, maintain the arrogant view that we might be at the top of the cosmic food chain and that the quest for extraterrestrial technological civilizations is an extraordinary claim that should be sidelined in favor of the search for microbes. How else can one interpret the top priority of the Astronomy & Astrophysics Decadal Survey to invest more than 10 billion dollars in the search for microbes and no federal funding in the search for extraterrestrial intelligent beings? Given the dismal brevity of our cosmic existence, we get comfort from the assumption that the we must be surrounded by lower life forms. I reject this popular view within present-day academia. Out of a sense of cosmic modesty, I define my goal throughout the remainder of my scientific career to seek evidence for a more accomplished sibling of our family of intelligent civilizations. If such evidence will be found, the next Copernican revolution would be that we are not at the intellectual center of the Universe. *** Before my morning jog at sunrise, I had received the following uplifting email from the Finnish artist, Antti Railio: “Hello Mr. Loeb. My name is Antti Railio, I am a Finnish singer/artist. I have been following your work for few years now and I am really happy to see a scientist who practices real science with the correct attitude towards it. I also have had an interest on the UAP/UFO phenomenon since the 1990’s since I have witnessed along with other people the phenomenon of bright orbs up upon the ocean here in Finland in my home town of Kristiinankaupunki. Also, I had an experience when I was a child which left me with 7 Stiches on my left palm… Well, that is beside my letter to you… I wanted to write to you, since I am not a scientist, but I have a curious mind, and it seems I tend to have Ideas or theories that time and time again seems to be after sometimes decades validated by scientists. For example, I had a theory that our universe might be inside a black hole and possibly the multiverse is like a bunch of soup bubbles. I had this idea 20 years ago… And since few years ago I read that this is now a well thought theory… I also have had a theory that life on earth had its origins somewhere else possibly the same life source that has been spread through the universe by panspermia. And I somehow am almost certain that this is the case. Anyway, my main reason for contacting you is this new theory I have… I just had an idea a few days ago popped to my brain! What would you think of this? You know the theory of white holes being the theorized flip sides of a black whole, but that we have not yet been able to seen or proven their existence ones… My theory is this: We are all made of the same material that exists inside the Sun as they say and Sun gives us life and illuminates the whole solar system… What if stars are the other side of a black holes, a reverse singularity! If I am not wrong a black hole appears in 3-dimensional space as a sphere? So my theory is that one of the reasons the Sun’s temperature is far more greater farther from its surface, is also driven by the forces pushing through the matter from a far distant black whole that is at the same time at the other side of the sun, so that it is occupying basically the same space as the Sun and at the same time it is connecting our solar system with another one somewhere where the black hole resides… Also the black hole’s immense gravitation would keep the sun at its form, but since it is constantly feeding in from the other side it has to disperse the energy gradually away thus the heat and photons would then be the Sun’s source of light and energy… The immense gravitation would still bleed through its presence over to this side keeping the planets locked in their places… Also, that would make sense in another theory connecting to UAP… It would make sense that higher beings would be aware of this and could use stars as a map of “jump points” to travel vast distances by using portals created by the universe… You know, sometimes the obvious is hiding right in front of our eyes… ;) That is my newest theory but I lack the scientific knowhow to even start to calculate the mathematics or the more technical sides of this theory, so I leave it to you as a fun theory or perhaps something to be thinking about … :) With the most respect and admiration Thank you so much for your time! Also, I am super excited about your Galileo Project! And secretly wish to grow up and start my scientific career. But maybe I am better at singing and performing… Yours truly! -Antti Railio” My response was as follows: “Dear Antti, Thank you for reaching out to me and for your kind words. Your idea about panspermia might very well be correct. For the latest update, see my essay from last week: https://avi-loeb.medium.com/impact-survival-of-microbes-highlights-the-feasibility-of-panspermia-45b7c6bc78dd It is possible that our Universe is embedded inside a black hole but we have no evidence for that. A black hole is characterized by a singularity at its venter (a place where the curvature of spacetime diverges), very different from the nearly uniform conditions in the observable volume of the Universe. Regarding the Sun and other stars: we can explain their properties, including their internal structure — which is probed by sound waves, as a result of nuclear fusion being their source of energy. Once they consume their nuclear fuel, they die and we see their remnants in the forms of white dwarfs (for Sun-like stars), neutron stars and black holes (for stars more massive than 8 solar masses). A white hole was conjectured as the source of energy for quasars or gamma-ray bursts, but these sources of light are well explained by a model involving the infall of matter into a black hole. Keep up with your creative work. Avi” ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

Image credit: Dr. Omer EldadiMy Medium.com readership has grown to 140,000 followers. Each one of you represents something I deeply value: a mind that refuses to accept easy answers. Today, I’m inviting you to participate in a new academic study. I am collaborating with Prof. Gershon Tenenbaum, Prof. Nancy Cooke, and Dr. Omer Eldadi on research examining how people evaluate digital media content — the images and videos we encounter every day. Over the past four months, various YouTube channels used AI to generate videos of me, by imitating my image and my voice to spread misinformation with content that I do not approve of. One of the channels accumulated millions of views before it was identified and removed. Many people had not noticed that the videos were fabricated. That experience changed how I think about what we see and what we trust. Take the survey (here) https://idc.az1.qualtrics.com/jfe/form/SV_1ReVxdIt6Jr9BOu The world is changing faster than our eyes can keep up. This study asks something simple: when you look at images and watch short videos, what are your impressions? There are no trick questions and no right or wrong answers. We want to understand how people like you — thoughtful, scientifically engaged individuals — experience visual content in today’s media environment. Your participation takes of order 10 minutes. The survey is completely anonymous, and the results will be published in a peer-reviewed journal and shared here with all of you. In science, we follow the evidence wherever it leads. In this study, you are the evidence. Your perception, your judgment, your instinct — that is what we are measuring. Four months ago, thousands of you participated in our study on beliefs about extraterrestrial intelligence. Your willingness to contribute to real research is what makes this community extraordinary. Take the survey (here) https://idc.az1.qualtrics.com/jfe/form/SV_1ReVxdIt6Jr9BOu I hope you will lend us your eyes once more. With gratitude, Avi Loeb ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

Cells of the microorganism Deinococcus radiodurans after high-pressure impacts, imaged by a Transmission Electron Microscope. The cells impacted at 1.4 giga-pascals (SH 1.4 GPa) harbor similar morphology and cell-wall membranes as the unimpacted cells (SC). In contrast, cells exposed to 2.4 giga-pascals (SH 2.4 GPa) show some internal (filled black arrow) and cell wall (open black arrow) damage. (Image Credit: L. Zhao et al. 2026)Through five peer-reviewed papers, published here, here, here, here and here, I have explored with my students and postdocs the possibility of the transfer of life, so-called panspermia, in exoplanetary systems like TRAPPIST-1 as well as throughout the Milky-Way galaxy -including in the dense stellar environment of the Galactic center. An interstellar gardener could enhance the cross-fertilization of planets beyond the random chance of impacts by microbe-carrying rocks. As I proposed here, our civilization could choose to seed the Milky-Way galaxy with life from Earth by launching a capsule with microbes, nutrients and a power source, on a collision course with an interstellar object like 3I/ATLAS which will carry our package to interstellar space and potentially disperse its content once it arrives to the habitable zone of another star. This deliberate life-delivery system would be far more consequential than the Golden Record sent onboard the Voyager spacecraft, which only contained an advertisement message about our civilization for anyone out there who might care to read it. The possibility that interstellar object might serve another purpose was supported by the discovery of organic molecules on 3I/ATLAS by the SPHEREx Space Observatory (as discussed here). Some interstellar object might be Trojan Horses, appearing as natural comets from the outside but carrying a technological package inside. The natural transfer of microbial life within rocks is certainly possible. A Martian rock named ALH84001 arrived to Earth’s surface without being heated to more than 40 degrees Celsius since its ejection from the surface of Mars (as reported here). Microbes could have survived in the interior of this rock. In fact, Mars and Earth exchanged numerous such rocks in their early history and could have shared the same forms of life in liquid water given their similar surface conditions and composition. Life transfer could have happened among adjacent members of other tightly-packed planetary systems, such as the seven rocky planets of the star TRAPPIST-1 (as I discussed here). A new paper published this month here subjected microorganisms to controlled extreme pressures for short periods and assessed their survival. The study found that microbes can survive extreme pressures of up to 20,000 larger than the atmospheric pressure on Earth (corresponding to about 2 giga-pascals), that may arise in asteroid impacts. This means that microbes could stay alive as rocks are ejected from the surface of planets as a result of spallation triggered by a meteor impact. The complementary question is how long could microbes survive in the harsh conditions of space, which include freezing temperatures and bombardment by cosmic-rays and UV radiation without essential nutrients. Their lifespan under these extreme conditions would determine how far they can travel in space before landing on the fertile ground of a new planet. Would these microbes fertilize the new ground on which they land with their genetic material like undamaged dandelion seeds carried by the wind? The new paper demonstrates that the specific extremophile Deinococcus radiodurans has an outstanding ability to survive the extreme transient pressures associated with impact-induced ejection from Mars. Earlier work has demonstrated that this microorganism can survive the radiation, cold, and desiccation associated with interplanetary transport. Mars is a smaller body than Earth which therefore cooled to habitable conditions before Earth. Given the above experimental results, it is possible that we are all Martians since life was delivered to Earth by Martian rocks in the form of the Last Universal Common Ancestor (LUCA) about 4.2 billion years ago (as reported here). In that case, the first humans to go to Mars might feel as if we are returning to their childhood home. By now, Mars is a desert without any liquid water on its surface. The loss of its vitality at the middle of its history, triggered by the loss of its atmosphere a few billion years ago, might not have been totally fatal because its descendants might visit back it back deliberately on a human-made spacecraft. What started as a random fluke of nature, panspermia, may come full circle as a deliberate transfer of life on technological equipment, directed panspermia. The story of life on Mars and Earth carries an important lesson. Sometimes when your life turns miserable at an old age, it is your children from long ago who may come to visit you on your deathbed and revive your prospects to thrive all over again. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

“There are plenty of fish in the sea.” `Are we alone?’ Is the most romantic question in science. This image, obtained by Webb telescope, shows a stellar nursery, the Tarantula Nebula, with tens of thousands of young stars shrouded in cosmic dust. (Image Credit: NASA/ESA)Do we have cosmic neighbors? To find out, we can use powerful telescopes and remotely search for technological signatures of distant extraterrestrial civilizations in the form of electromagnetic signals, artificial lights, industrial pollution or megastructures. Alternatively, we could check for any packages delivered to our mailbox. U.S. Government data might help us make advances on the second option. This week, the White House registered two new U.S. Government domains: alien.gov and aliens.gov, according to publicly available federal records. These domains are not related to immigration policy but rather to the announcement made President Trump a month ago: “Based on the tremendous interest shown, I will be directing the Secretary of War and other relevant departments and agencies to begin the process of identifying and releasing government files related to alien and extraterrestrial life, unidentified aerial phenomena (UAP), unidentified flying objects (UFOs), and any and all other information connected to these highly complex but extremely interesting and important matters. GOD BLESS AMERICA!” Shortly afterwards, the Secretary of War Pete Hegseth stated that the Pentagon started to actively work on President Trump’s directive. The White House spokeswoman, Anna Kelly, replied to different journalists with the same email message: “Stay tuned!” Her statement included the same alien emoji that Secretary Hegseth used on social media when he reposted Trump’s directive last month. 👽 The two new government domains are not yet connected to active websites with any content. What might their content include in the future? In the best-case scenario, the public might have access to high-resolution images or videos that show objects whose dynamics or appearance indicate without any doubt non-human made technologies. In the worst-case scenario, we will have access to inconclusive data with insufficient information to conclude anything about its nature. A disappointing release could include documents in which the most revealing information is redacted. The worst-case scenario would fuel conspiracy theories but will not promote a realistic assessment of whether there’s a “there” there with qualities that might revolutionize science as we know it — either by revealing new physics or by offering a new perspective on our place in the Universe. U.S. Government sensors are monitoring Earth continuously for national security purposes and could be the first to detect rare objects that represent non-human made technologies. In such a case, the related data would be kept classified if its origin is not understood. As a scientist, I would love to help the U.S. Government figure out the meaning of any such data. Unraveling the nature of UAP is important for aviation safety as well as national security. But most importantly, it could usher in the next Copernican revolution. Historically, UAP discussions were sabotaged by misinformation and unsubstantiated claims. This deterred mainstream scientists from seriously engaging with it. However, in recent years the subject gained credibility because the government sensors are of unprecedented quality and the anomalies they expose are impossible to ignore. When studying UAP, it is important to keep in mind what the Nobel laureate physicist Richard Feynman said: “The problem is that people are educated just enough to believe what they have been taught, and not educated enough to question anything from what they have been taught.” The Galileo Project under my leadership is collecting new scientific data in search for UAP from its three functioning observatories. Members of the Galileo research team know that they can call me in the middle of the night if they discover unambiguously a UAP among the millions of objects that our observatories monitor. Yesterday, I reviewed the latest progress in the Galileo Project during a physics & astronomy colloquium accompanied by a public lecture and book signing at Notre Dame University in Indiana. Avi Loeb in Notre Dame University with statue of the Virgin Mary atop of the Golden Some in the background. (Image credit: Professor Laszlo Forro; March 18, 2026)In 12 days, I am scheduled to give another public lecture at the Frost Planetarium in Miami, Florida. *** What will be the actual content released in the new website aliens.gov? Perhaps, the best is yet to come. It is important to stay optimistic, because life is sometimes a self-fulfilling prophecy, especially if we view it with humility as a learning experience. There is no reason to assume that we are at the top of the food chain, cosmologically speaking. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

The Square-Kilometer-Array, located in South Africa and Australia, will offer new opportunities for eavesdropping on leakage of radio signals from extraterrestrial civilizations. (Image Credit: SKAO)The news about our technological era has been propagating at the speed of light for roughly 120 years, and reached only 20,000 nearby star systems. This constitutes a tiny fraction of only one part in ten million of the total number of stars in the Milky-Way galaxy. But it is important to recognize that in the next few centuries this number will grow in proportion to that time cubed, meaning that in a millennium — it will be about a thousand times larger. The growth will slow down to a scaling with time squared after the next millennium because most Milky-Way stars are distributed in a two-dimensional disk whose thickness is of order a thousand light-years. If there are predator civilizations out there, this volume growth could have dramatic implications for the long-term survival of humanity because they may regard us as a threat and arrive at Earth to destroy us. Our risk of being noticed increases rapidly with the number of technological centuries we endure. And after being noticed by a predator, we might still not hear from a predator for a period corresponding to their travel time to reach us, which could be as long as millions to billions of years if they use rocket technologies or hundreds of years if they operate weapons, such as a powerful laser beam, that travel at the speed of light. The saving grace is that as our signals move out, they also get fainter, reducing the chance of them being noticed in the background noise of the Milky-Way galaxy. In a paper (accessible here) that I co-authored with Matias Zaldarriaga in 2007, we showed that the new generation of radio observatories on Earth could detect radio broadcast leakage from an Earth-like civilization out to a distance of order a hundred light years. Such a radio signal will show up as a series of narrow spectral lines that do not coincide with known atomic or molecular lines. For example, the high spectral resolution attainable with the forthcoming Square-Kilometer-Array will allow us to monitor the periodic Doppler shift of the broadcast lines over the planet’s orbital period around the parent star. Determination of the parent star mass through observations of its spectrum could then be used to infer the inclination, semi-major axis and eccentricity of the planet’s orbit. This, in turn, will allow us to estimate the temperature on the planet’s surface and to assess whether it can support liquid water or life as we know it. In other words, a twin-civilization could eavesdrop on us right now if it is located within our radio bubble out to 120 light years. But many more extraterrestrial civilizations may be aware of the habitability of planet Earth as they can observe it transiting the Sun. The Earth’s transit of the Sun could be seen from up to a billion stars, about 0.5% of all stars in the Milky-Way galaxy. The main scenario that we should lose sleep about is of alien predators who noticed Earth a long time ago and decided to monitor the situation from up close, forecasting that it may lead to the development of space technologies that pose a threat to them. If they have camped in the outer solar system, they can respond to anything happening on Earth within decades at the speed of chemical rockets. We might notice their gadgets flying around in the form of anomalous solar-system or interstellar objects. For all these reasons, we must stay alert to the cosmic news delivered to us on a daily basis by the NSF-DOE Rubin Observatory. We are used to thinking about the Universe as an independent entity that has nothing to do with our actions here on Earth. But this paradigm could break down as soon as we realize that someone else out there is watching us and responding to what we do. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

Two-dimensional visualization of an Alcubierre warp drive, showing the opposing regions of expanding and contracting spacetime that displace the central region. (Image Credit: Wikimedia)Trustworthy military pilots report about Unidentified Aerial Phenomena (UAP) that exceed the performance envelope of human-made technologies. In a testimony before Congress, the Retired Navy Commander David Fravor reported seeing in 2004 white `Tic-Tac’ shaped objects that are of order 10-meter long , descending about 30 kilometers in less than a second. Some interpreters were quick to suggest that UAP might be warp drives invented by magical thinking in science fiction narratives. But there is also a scientific counterpart to this concept. By warping space inside a bubble, a spacecraft inside the bubble could be propelled to a spatial speed faster than light. This possibility is manifested in the Alcubierre drive, a theoretical steady-state solution to Einstein’s equations of General Relativity. The Alcubierre metric in the time (t) and space (x,y,z) coordinates can be written as: , where is the speed of the warp bubble, is the shape function of the bubble and is the radial distance from the bubble center located at . The creation of such a bubble requires an exotic substance with negative energy density, in violation of the Weak Energy Condition of Einstein’s General Relativity. We do not know if such a substance exists. If it exists, it might be possible to create a time machine and go back in time. In a warp bubble moving at a speed comparable to the speed of light, the distortion of spacetime is large — of order unity. When such a spacetime structure moves through air, it would move around the air molecules at roughly the speed of light during a period of order the light crossing time of the bubble. The inevitable collisions of these molecules with each other will heat up the air around the bubble to an extremely high temperature, triggering the formation of a fireball. The supersonic motion of the air would inevitably lead to dissipation of heat and an outward moving blast wave that would cool through the emission of radiation. How bright might the fireball be? Assuming energy conservation, the heat deposited in air would eventually be radiated away. For a bubble that moves molecules around near the speed of light, the dissipated power could be at most of order the rest mass energy of the air within the bubble volume divided by the light crossing time of the bubble. For an object of 10 meters in size, this corresponds to a maximum radiation power of roughly ten times the luminosity of the Sun. An Alcubierre Warp Drive on the length scale of the `Tic-Tac’ objects reported by Navy Commander David Fravor could shine brighter than the Sun. Clearly, this was not observed in 2004. In reality, the radiative luminosity would be somewhat smaller because the reduced cross-section for molecular collisions at relativistic velocities but not enough to make the fireball faint enough to be consistent with Fravor’s testimony. Even though the luminosity scales with the area of the warp bubble, it could still approach a tenth of the Sun’s luminosity for a meter-size bubble. The luminosity scales with the air speed cubed, but that speed cannot be smaller than 10 kilometers per second based on Fravor’s testimony. At that minimum speed, a meter-size bubble would still shine with a power of 30 terawatts, ten times larger than the average electric power consumption throughout the world. Surely, such a bright source of light was not seen in 2004. Of course, we can always imagine new physics but any such physics should be contemplated only if supported by indisputable evidence from exquisite scientific instrumentation. Is there a caveat to Fravor’s report? When driving in a highway, we might see a black car behind us in the rearview mirror and then shortly thereafter notice the same type of black car in front of us. Without verifying that the license plates are identical, our eyewitness testimony does not mean that we saw the car moving at an extraordinary speed. Our two data points might be associated with two independent cars coming in and out of view. This caveat calls for a rigorous scientific study of UAP — triggered by Fravor’s repoty, which is precisely the rationale behind the Galileo Project that I am leading. As of now, the Galileo research team is able to measure distances to objects in the sky through the method of triangulation from multiple observing units (as discussed here). This allows to unambiguously measure the velocity and acceleration of objects with well-calibrated scientific instrumentation. Recently, we invited here the public here to be engaged in our data analysis as a way of establishing the ground truth for our machine-learning software in its search for UAP. Here’s hoping that in the coming months and years, the Galileo research team will shed new light on the origin of the unusual `Tic-Tac’ objects reported by Navy Commander David Fravor. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. Professional website: https://lweb.cfa.harvard.edu/~loeb/ Social media: https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article