Astronomy and Stars
Discussions about astronomy and stars. As we look further out what can we find in the universe beyond Earth's atmosphere?
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(Image credit: goodmenproject)Today, I had received the following unusual request: “Dear Dr. Loeb, My name is Ashleigh Dunn and I work at Misawa Air Base in Aomori Prefecture, Japan. We are hosting a community event titled “Together Under the Same Sky” in celebration of International Observe the Moon Day. The purpose of this event is to bring together U.S. Forces and JASDF families by highlighting the one thing every person on Earth shares — the sky above us. We would be honored if you would consider providing a short pre‑recorded video message for this event. Your work in astrophysics and your leadership in exploring bold ideas about extraterrestrial life have sparked gl…
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Actors Brandon Routh (right) and Avi Loeb on the set of “Sol Hershowitz’s Guide to Extraterrestrial Life” in New York City on May 12, 2026. (Image credit: Avi Loeb)Today was my first experience as a professional movie actor. Shortly, I will be boarding an airplane back to Boston from New-York City — where I appeared in a cameo role, playing myself on the movie set of “Sol Hershowitz’s Guide to Extraterrestrial Life”. This is a great privilege that is not offered often. I had never seen Brad Pitt play himself in a movie. I was amazingly lucky to be featured on a movie set while lacking basic skills to play other characters. People who know me well, including my wife, would…
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(Image credit: Greg Wyatt)The chemistry of life-as-we-know-it requires carbon and oxygen. The universe spent only a few minutes at the high temperatures that enable fusion of protons and neutrons into carbon or oxygen and so it produced negligible amounts of these heavy elements shortly after the Big Bang. But a hundred million years later, the first stars condensed out of the primordial gas of hydrogen and helium and were able to produce carbon and oxygen in their interiors over millions of years. These first stars were massive based on theoretical calculations that I performed with my students and postdocs thirty years ago (and are summarized in my textbooks “How Did th…
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(Image credit: The Hill’s Rising, 2.14M subscribers)Below is a transcript of a latest interview I had today with The Hill’s Rising, one out of the 30 interviews I had over the past three days, available in video form here. The questions are marked below with the label Q, and my answers with A, respectively. In an hour, I will be boarding a plane to New-York City to appear in a cameo playing myself on the movie set of “Sol Hershkowitz’s Guide to Extraterrestrial Life”. It should be straightforward for me to play myself, , as you may tell from the interview appended below. *** Q: The Trump administration released the first batch of so-called UFO files last week. Some of the…
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A photo from 1887 of a cowboy settler in the American Wild West frontier. Note the resemblance of the hat to a flying saucer. (Image credit: Wikimedia)NASA targets early 2028 for the Artemis IV mission to land human astronauts on the South Pole of the Moon. This will constitute a major milestone towards establishing a long-term human presence on the lunar surface. Is this the beginning of a new Wild West frontier without natives? A permanent Artemis base camp on the lunar South Pole would serve as a testbed for developing technologies of power supply and resource utilization, needed for future human missions to Mars. The base camp would offer a fresh start where a new com…
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(Image credit: Greg Wyatt)Albert Einstein told a friend: “When I examine myself and my methods of thought, I come close to the conclusion that the gift of imagination has meant more to me than any talent for absorbing absolute knowledge… All great achievements of science must start from intuitive knowledge. I believe in intuition and inspiration…. At times I feel certain I am right while not knowing the reason.” This echoes his well-known assertion that for creative scientific work: “Imagination is more important than knowledge.” Einstein’s imagination was the highest manifestation of natural intelligence. The total capital expenditures by major U.S. tech companies in Art…
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(Image credit: Scientific American)In recent months, two papers (accessible here and here) suggested the existence of an abundant population of negative mass objects in the Universe. Albert Einstein’s theory of gravity, General Relativity, allows negative masses, as discussed in a seminal 1957 paper published here by the physicist Herman Bondi. In 2015, Robert Forward showed in a paper available here how negative masses can be used for propulsion without fuel. But as I explained in a recent essay here, we have no idea whether negative masses can be constructed in reality. In fact, their existence would create fundamental problems in our current understanding of the physic…
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(Image credit: Wired)In his book “Critique of Pure Reason”, the German philosopher Immanuel Kant noted: “The light dove, in free flight cutting through the air the resistance of which it feels, could get the idea that it could do even better in airless space.” Indeed, a bird cannot fly without air for the same reason that a swimmer cannot swim in an empty pool. Similarly, interaction with other people sometimes slows us down but it also allows us to move forward. The latest experience of AI friendship gives some members of Generation Z (born between 1997–2012) and Generation Alpha (born after 2013) the illusion that they can go through life without human friends. At first…
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The Ingenuity helicopter on Mars. (Image credit: NASA)Helicopters fly by using an engine to spin rotor blades, which create lift and thrust by pushing air away, similarly to a bird flapping its wings or a swimmer moving limbs in water. The spinning blades act as rotating wings, generating low net pressure above and high pressure below to produce lift. A tail rotor or a counter-rotating blade system is essential to cancel torque, preventing the body from spinning in the opposite direction. Forward motion is triggered by tilting the blade plane. An image taken from the Orion capsule on April 3, 2026, showing the thin atmosphere of Earth against the blackness of space. (Imag…
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Henry Thoreau’s cabin site. (Image credit: The Walden Woods Project)When I met Sergey Brin and Mark Zukerberg in Silicon Valley a decade ago, their net worth was about $30–40 billion. By now, it is 6 times larger. Over the same decade, the net worth of Elon Musk and Jensen Huang grew by a factor of about 60. With AI advancing rapidly, the latter two are projected to become trillionaires over the next few years. This level of wealth is staggering. What is the best way to use it? Reflecting back on my life, my career goal was to earn just the amount of money necessary to buy me freedom. By freedom, I mean the pleasure of pursuing my creative work while minimizing the time s…
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The vacuum Casimir force on two plane-parallel plates. (Image credit: Wikimedia)The optimal propulsion of a payload to space is without fuel. Our current space rockets rely on carrying the fuel along with the payload for the ride. Most of the fuel energy is wasted in this way, allowing the terminal speed of the payload to grow only logarithmically with increasing fuel mass. The most elegant way out this conundrum is to create artificially a negative mass. Adding a negative mass of equal magnitude to the payload mass would make the total mass of the system on the launch pad zero. This means that the Earth’s gravity will not be pulling the system down. Ignoring friction wit…
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(Image credit: Newsmax)On April 29, 2026, an earthquake and 15 aftershocks occurred in southern Nevada near the highly restricted Area 51 military installation. The first quake of magnitude 4.4 struck at a depth of around 4 kilometers which is considered very shallow. The aftershocks, ranging in magnitude from 1.5 to 3.7, struck at a similar depth. This is consistent with geological expectations based on the location of faults and seismicity in that region. To produce such an earthquake artificially requires an explosion energy of 2–3 kilotons of TNT, corresponding to a low-yield tactical nuclear weapon (as calibrated by USGS here). Below is a transcript of a new intervie…
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A selfie taken by the NASA rover Perseverance, on July 23, 2024. Is Martian life a selfie of terrestrial life? Discovering ancient oil on Mars could answer this question. (Image credit: NASA)Most geologists believe that oil on Earth originated mostly from the remains of ancient marine microorganisms — primarily plankton, algae, and bacteria — that accumulated on seafloors, were buried under layers of sediment, and transformed under the extreme heat and pressure into oil and gas. Most of the organic raw materials are traced to the Mesozoic era, 66 to 252 million years ago, but some deposits are much older, originating from algae and bacteria in ancient seas. Life started o…
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An image of the asteroid moonlet Dimorphos, taken by NASA’s DART spacecraft 11 seconds before impact at a distance of 68 kilometers. Dimorphos is about 160 meters in length. (Image credit: NASA/Johns Hopkins APL)The NSF-DOE Rubin Observatory in Chile is expected to discover dozens of new interstellar objects within the next decade. These visitors to our cosmic backyard will be flagged by their speed exceeding the value needed to escape from the pull of the Sun’s gravity. Near the Earth’s orbit around the Sun, the escape speed is 42.1 kilometers per second, just a square-root of 2 larger than the Earth’s orbital speed at the Earth-Sun separation (AU). 3I/ATLAS arrived to o…
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(Image credit: Greg Wyatt)Following the success of the Artemis II mission, many kids were inspired to go to the Moon. As responsible adults, we should inform our kids that although a trip to the lunar surface sounds like fun, the experience would be worse than breathing asbestos. The rocky surface of the Moon was shattered into sharp powdery and highly abrasive dust generated by asteroid impacts over the past 4.5 billion years. The lunar dust resembles tiny glass fragments, and poses severe hazards to astronaut health. Any construction project of a sustainable lunar base will inevitably raise dust from the lunar surface. This dust will not settle down quickly because the …
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(Image credit: The Sun)Could artificial intelligence (AI), machine learning (ML), large language models (LLM) or natural language processing (NLP) help us figure out the nature of Unidentified Flying Object (UFOs) or Unidentified Anomalous Phenomena (UAP), by analyzing verbal reports from humans? Today, I received an email from a group of researchers who stated: “We’ve been working on a machine learning project that classifies reports from the National UFO Reporting Center by narrative “dramaticness,” essentially modeling the language and content of witness reports to distinguish brief, ambiguous observations from highly detailed extraordinary accounts. The pipeline combi…
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A flare from the Sun. (Image credit: NASA)The most abundant stars are dwarf stars with a tenth of the mass of the Sun. They live for trillions of years (as calculated here), over a hundred times longer than the lifespan of the Sun. If intelligent life was common around low-mass stars, we would find ourselves next to a dwarf star in the future. Why do we exist near the Sun right now, cosmologically speaking? This is a question that I have asked a decade ago in a paper published in the Journal of Cosmology and Astroparticle Physics, accessible here. Since dwarf stars are fainter than the Sun, the habitable zone around them — where liquid water may exist on the surface of an…
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(Image credit: iStock/Getty)The White House, Congress and several federal agencies are currently investigating a loosely defined list of recent deaths and disappearances of about ten scientists and staff with potential ties to classified research. Congressmen James Comer — who chairs the House Committee on Oversight and Government Reform, and Eric Burlison — who chairs the Subcommittee on Economic Growth, Energy Policy and Regulatory Affairs, stated officially here that they are investigating the cases as a potential threat to national security. Publicly available information shows the circumstances surrounding these deaths and disappearances vary widely. Related families…
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(Image credit: Getty/Futurism)One of the surprising anomalies of 3I/ATLAS is its exceedingly high fraction of deuterium, amounting to one deuterium (D) in 100 hydrogen (H) atoms in water (as reported here) and one deuterium in 30 hydrogen atoms in the organic molecule of methane (as reported here). The latter D/H fraction of 3.3% is a thousand times above the average cosmic value elsewhere in the Universe. During the Manhattan Project, Edward Teller raised the speculative possibility that the fireball from an atomic bomb explosion might ignite the atmosphere by triggering a fusion reaction of nitrogen (14N) nuclei (as described here). In response, Hans Bethe calculated th…
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The interstellar object 3I/ATLAS appears as the central fuzzy dot in this recent image, taken by the Hubble Space Telescope on April 10, 2026. (Image credit: HST/NASA/T. Scarmato)By now, 3I/ATLAS is at a distance of a billion kilometers or 6.7 times the Earth-Sun separation, well beyond Jupiter. Our interstellar visitor appears as a fading dot, similar to the way it looked when it was first spotted in telescope images nearly a year ago, except that right now it is heading away from us back to interstellar space. Given how well aligned its trajectory was with the orbital plane of Earth around the Sun, we might never witness a visitor like it in our lifetime. Observed brigh…
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Schematic illustration of the progenitor of a supermassive black hole in the form of a supermassive star. After the accretion of gas into the supermassive star ends, the star contracts, ignites hydrogen burning, and re-expands into a late phase of instability. Pulsation-driven mass loss then proceeds through discrete ejection episodes that remove weakly-bound envelope material. Earlier shells expand to large radii, whereas the final pre-collapse ejection remains compact and dense, setting the immediate circumstellar environment which explain Webb telescope data on the observed population of `little red dots’. The ejecta carries a characteristic abundance pattern which is …
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(Image credit: newspaceeconomy.ca)by Konrad Szocik (1) and Abraham Loeb (2)(1) Department of Social Sciences, University of Information Technology and Management in Rzeszow, Poland; (2) Astronomy Department, Harvard University, 60 Garden Street, Cambridge MA 02138, USA (Submitted for publication in a peer-reviewed journal) Abstract Recent work on the Loeb Scale has provided astronomy a structured framework for assessing anomalous interstellar objects, including a quantitative mapping of a classification ranking, its evolution with the addition of data, and a broader observational strategy for firming its verdict. What remains unclear is the epistemic and methodological me…
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(Image credit: Greg Wyatt)Life on Earth started with the Last Universal Common Ancestor (LUCA), dated to 4.2 billion years ago (as deduced here). Humanity’s first artificial satellite was Sputnik, launched away from Earth’s surface on October 4, 1957. It is commonly assumed that this was the first technological satellite around Earth. However, suppose intelligent life emerged when Earth was 94% of its current age (which is 4.54 billion years), namely 272 million years ago. In that case, a technological civilization could have started launching satellites a few million years after their intelligence emerged — similarly to humanity’s case. About 252 million years ago, this …
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An Inspiring Visit of Congresswoman Anna Paulina Luna to Avi Loeb’s Office at the Harvard College Observatory(Image credit: Devesh Nandal)After sitting together side-to-side on the `observers seat’ of the historical Great Refractor telescope from 1843, congresswoman Anna Paulina Luna and I walked around the display of the women “computers” of the Harvard College Observatory who pioneered major discoveries in Astronomy over a century ago. They included Henrietta Swan Leavitt, who discovered the luminosity-period relation of pulsating Cepheid stars. Measuring the pulsation period of these stars allowed to determine their distance, just like reading off the label of a 100-Wa…
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The symmetric system of three jets emanating from the nucleus of the interstellar object 3I/ATLAS (separately from the primary anti-tail jet) after the circularly symmetric glow was removed by the Larson-Sekanina rotational gradient filter, based on a Hubble Space Telescope image taken on November 30, 2025. (Image credit: T. Scarmato and A. Loeb 2026)A new paper (accessible here) that I co-authored today with Toni Scarmato analyzed images of the interstellar object 3I/ATLAS, taken by the Hubble Space Telescope over the past five months. After removing the circularly-symmetric glow around the nucleus of 3I/ATLAS using the Larson-Sekanina rotational gradient filter, we iden…
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In his seminal work Astronomia Nova (1609), Johannes Kepler commented on the mutual gravitational attraction between the Moon and Earth. 417 years later, the Artemis II crew circled the Moon and returned to Earth, sampling the gravitational potential wells of the two bodies. The cost was 4.1 billion dollars. What would NASA do with an infinite budget? (Image credit: Greg Wyatt)Today I was asked by students: “If you had an infinite research budget, how would you allocate it?” This is an interesting question to be asked just a week after the White House released the FY2027 Budget Request with major proposed cuts to science agencies. Cutting fundamental science while nurturi…
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(Image credit: Getty Images/HISTORY Channel)Below is the transcript of a Questions and Answers session that I had on April 13, 2026 with a class full of students in Sweden, taught by Professor Henrik Nordvall. *** Q: First, we will give you the chance to say a few words about yourself. A: I haven’t changed much since I was a small child. I grew up on a farm and was interested mainly in nature. That’s pretty much what I am right now. I don’t care how many likes I get on social media, and my main focus is in trying to understand our cosmic environment, nature, without any prejudice, without assuming that we are at the top of the food chain. Q: The first question relates to …
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(Image credit: James O’Brien/Quanta Magazine)The alignment problem is often phrased as the fundamental challenge of ensuring that artificial intelligence (AI) acts in accordance with human goals and values, without adopting harmful biases or pursuing goals with unintended consequences. This is often viewed as a one-side alignment, anchoring AI to the intentions of humans. However, in any relationship between intelligent entities, both sides have to adjust to the qualities of the other. Here, I focus on a particular segment of society that must adjust to the new world-order in the age of AI: academia. Given the unprecedented performance of the latest AI system, it is time …
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(Image credit: Newsmax)Below is a transcript of a new interview I had this morning on Sunday Report of Newsmax in the company of former NASA rocket scientist, Olympia LePoint and Former NASA astronaut and USAF Colonel (Ret.), Terry Virts, with the anchor Bill Spadea (accessible in video form here). Bill’s questions are marked with WS, while Olympia’s answers are marked OL, Terry’s answers with TV my answers with AL, respectively. *** WS: Mission accomplished. The Artemis II crew of four receiving a hero’s welcome at Ellington Field in Houston, Texas. One day after splashing down off the coast of California, Artemis II commander Reid Wiseman had this to say to the crowd: “…
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(Image credit: ScienceDirect)The four astronauts on Artemis II were in space for 9 days and did not suffer any significant medical problems from the low gravity environment that they experienced. But for space journeys lasting years, it is necessary to produce an analog of Earth’s gravity in order to protect astronaut health. Without gravity, bones lose mineral density at a rate of about 1.5% per month and muscles atrophy rapidly. Bodily fluids move towards the head, potentially causing eye damage and brain swelling. There are two simple ways to produce artificial gravity. One is by accelerating astronauts on a rocket or any other propulsion system. The artificial linear …
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Splashdown of the Orion capsule of the Artemis II mission in the Pacific Ocean. (Image credit: NASA)The Artemis II spacecraft carried four humans to a distance record of 406,771 (~0.4 million) kilometers away from Earth. How significant is this accomplishment in a cosmic perspective? To gauge this feat, consider the cosmic ladder in distance jumps of roughly a factor of 10,000 per step. At a distance 10,000 bigger than the Artemis II record, lies the farthest planet in the Solar System, Neptune, of about 4.5 billion (4.5x10⁹) kilometers. Another factor of 10,000 brings us to the distance of the nearest star, Proxima Centauri, of about 40 trillion (4x10^{13}) kilometers. T…
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A visualization of the Artemis I spacecraft reentering Earth’s atmosphere. Artemis II is about to splash down in the Pacific Ocean on April 10, 2026. (Image credit: NASA)Today, April 10, 2026, the Artemis II Orion spacecraft will bring back to Earth four humans who reached farther than any human did. The reentry of Orion through the Earth’s atmosphere will start at 8:07 PM ET with a velocity measuring 30 times the speed of sound. Like a giant piston, it will push air supersonically and generate a fireball capped by a blast wave with a temperature of thousands of degrees. The safety of the astronauts during this dramatic phase relies on the successful insolation provided b…
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(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, …
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(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…
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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…
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(Image credit: Greg Wyatt)During a typical lifespan, a human experiences about one century of history. However, we rarely wonder what happened to early humans who lived during the single century between 4.5400 million years ago and 4.5401 million years ago. Since then, there were as many as 45,400 additional centuries of human history for us to consider. The history of Earth extends even longer, by a factor of 1,000. In total, of order 45.4 million centuries had elapsed since the Earth formed. But even the Earth existed only during the last third of cosmic history. Our cosmic roots extend back to 13.8 billion years ago, when the Big Bang occurred. Each electron in the Uni…
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(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 Chi…
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(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 I…
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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 nuc…
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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 t…
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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 …
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(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 liv…
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(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, Vanc…
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(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 ca…
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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.…
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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 r…
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(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 …
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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, respectiv…
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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, makin…
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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…
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