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By NASA
Did you know some of the brightest sources of light in the sky come from the regions around black holes in the centers of galaxies? It sounds a little contradictory, but it’s true! They may not look bright to our eyes, but satellites have spotted oodles of them across the universe.
One of those satellites is NASA’s Fermi Gamma-ray Space Telescope. Fermi has found thousands of these kinds of galaxies since it launched in 2008, and there are many more out there!
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Watch a cosmic gamma-ray fireworks show in this animation using just a year of data from the Large Area Telescope (LAT) aboard NASA’s Fermi Gamma-ray Space Telescope. Each object’s magenta circle grows as it brightens and shrinks as it dims. The yellow circle represents the Sun following its apparent annual path across the sky. The animation shows a subset of the LAT gamma-ray records available for more than 1,500 objects in a continually updated repository. Over 90% of these sources are a type of galaxy called a blazar, powered by the activity of a supermassive black hole. NASA’s Marshall Space Flight Center/Daniel Kocevski Black holes are regions of space that have so much gravity that nothing — not light, not particles, nada — can escape. Most galaxies have supermassive black holes at their centers, and these black holes are hundreds of thousands to billions of times the mass of our Sun. In active galactic nuclei (also called “AGN” for short, or just “active galaxies”) the central region is stuffed with gas and dust that’s constantly falling toward the black hole. As the gas and dust fall, they start to spin and form a disk. Because of the friction and other forces at work, the spinning disk starts to heat up.
This composite view of the active galaxy Markarian 573 combines X-ray data (blue) from NASA’s Chandra X-ray Observatory and radio observations (purple) from the Karl G. Jansky Very Large Array in New Mexico with a visible light image (gold) from the Hubble Space Telescope. Markarian 573 is an active galaxy that has two cones of emission streaming away from the supermassive black hole at its center. X-ray: NASA/CXC/SAO/A.Paggi et al; Optical: NASA/STScI; Radio: NSF/NRAO/VLA The disk’s heat gets emitted as light, but not just wavelengths of it that we can see with our eyes. We detect light from AGN across the entire electromagnetic spectrum, from the more familiar radio and optical waves through to the more exotic X-rays and gamma rays, which we need special telescopes to spot.
In the heart of an active galaxy, matter falling toward a supermassive black hole creates jets of particles traveling near the speed of light as shown in this artist’s concept. NASA/Goddard Space Flight Center Conceptual Image Lab About one in 10 AGN beam out jets of energetic particles, which are traveling almost as fast as light. Scientists are studying these jets to try to understand how black holes — which pull everything in with their huge amounts of gravity — somehow provide the energy needed to propel the particles in these jets.
This artist’s concept shows two views of the active galaxy TXS 0128+554, located around 500 million light-years away. Left: The galaxy’s central jets appear as they would if we viewed them both at the same angle. The black hole, embedded in a disk of dust and gas, launches a pair of particle jets traveling at nearly the speed of light. Scientists think gamma rays (magenta) detected by NASA’s Fermi Gamma-ray Space Telescope originate from the base of these jets. As the jets collide with material surrounding the galaxy, they form identical lobes seen at radio wavelengths (orange). The jets experienced two distinct bouts of activity, which created the gap between the lobes and the black hole. Right: The galaxy appears in its actual orientation, with its jets tipped out of our line of sight by about 50 degrees. NASA’s Goddard Space Flight Center Many of the ways we tell one type of AGN from another depend on how they’re oriented from our point of view. With radio galaxies, for example, we see the jets from the side as they’re beaming vast amounts of energy into space. Then there’s blazars, which are a type of AGN that have a jet that is pointed almost directly at Earth, which makes the AGN particularly bright.
Blazar 3C 279’s historic gamma-ray flare in 2015 can be seen in this image from the Large Area Telescope on NASA’s Fermi satellite. During the flare, the blazar outshone the Vela pulsar, usually the brightest object in the gamma-ray sky. NASA/DOE/Fermi LAT Collaboration Fermi has been searching the sky for gamma ray sources since 2008. More than half of the sources it has found have been blazars. Gamma rays are useful because they can tell us a lot about how particles accelerate and how they interact with their environment.
So why do we care about AGN? We know that some AGN formed early in the history of the universe. With their enormous power, they almost certainly affected how the universe changed over time. By discovering how AGN work, we can understand better how the universe came to be the way it is now.
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Last Updated Apr 30, 2025 Related Terms
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By NASA
Explore This Section Perseverance Home Mission Overview Rover Components Mars Rock Samples Where is Perseverance? Ingenuity Mars Helicopter Mission Updates Science Overview Objectives Instruments Highlights Exploration Goals News and Features Multimedia Perseverance Raw Images Images Videos Audio More Resources Mars Missions Mars Sample Return Mars Perseverance Rover Mars Curiosity Rover MAVEN Mars Reconnaissance Orbiter Mars Odyssey More Mars Missions Mars Home 2 min read
Searching for the Dark in the Light
The Perseverance rover acquired this image of the “Hare Bay” abrasion patch using its SHERLOC WATSON camera (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals, and the Wide Angle Topographic Sensor for Operations and eNgineering), located on the turret at the end of the rover’s robotic arm. This image was acquired on April 18, 2025 (Sol 1479, or Martian day 1,479 of the Mars 2020 mission) at the local mean solar time of 12:53:57. NASA/JPL-Caltech Written by Eleanor Moreland, Ph.D. Student Collaborator at Rice University
Perseverance has been busy exploring lower “Witch Hazel Hill,” an outcrop exposed on the edge of the Jezero crater rim. The outcrop is composed of alternating light and dark layers, and naturally, the team has been trying to understand the makeup of and relationships between the light and dark layers. A few weeks ago, we sampled one of the light-toned layers, which we discovered was made up of very small clasts, or fragments of rocks or minerals, at “Main River.” Since then, we have learned that the dark layers tend to be composed of larger clasts compared to the light layers, and we’ve been searching for a place to sample this coarser-grained rock type. Sometimes, these coarser-grained rocks also contain spherules, which are of great interest to the science team because they provide clues about the process that formed these layered rocks.
Perseverance first looked at a dark layer at “Puncheon Rock” with an abrasion. We then examined a dark layer at “Wreck Apple,” near “Sally’s Cove,” but we could not identify a suitable surface to abrade. So, while team members searched for other locations to study the coarse-grained units and spherules, Perseverance drove south to “Port Anson.”
Perseverance acquired this image of the “Strong Island” workspace near Port Anson using its onboard Front Left Hazard Avoidance Camera A (https://science.nasa.gov/mission/mars-2020-perseverance/rover-components/#eyes). This image was acquired on April 12, 2025 (Sol 1473, or Martian day 1,473 of the Mars 2020 mission) at the local mean solar time of 12:50:32. NASA/JPL-Caltech Port Anson was intriguing because, from orbit, it showed a clear contact between the light layers of Witch Hazel Hill and a distinct unit below it. And, although the rocks below the Port Anson contact do show interesting compositional differences with those of Witch Hazel Hill, they weren’t the coarse-grained rocks we were looking for. We still performed an abrasion there, at Strong Island, before driving back up north for another attempt at investigating the coarser-grained rocks.
We aimed for “Pine Pond,” which neighbors “Dennis Pond,” to abrade at “Hare Bay.” With the data just coming down over the weekend, the team will be hard at work to figure out if we captured the coarse grains and spherules, and if it is representative of rocks we have seen before or not. The image below is a close-up of this most recent abrasion patch at Hare Bay — what do you think? Stay tuned to find out!
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Last Updated Apr 25, 2025 Related Terms
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ECF 2024 Quadchart McGuirk.pdf
Christopher McGuirk
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This project will investigate and develop improved storage methods for the fuels needed to generate electrical power in places where sunlight is not available. The effort will focus on particularly tailored materials called Metal Oxide Frameworks, or MOFs, that can be used to store methane and oxygen. The methane and oxygen can be reacted in a solid oxide fuel cell to generate electricity, and storing them in a MOF could potentially result in significant mass and cost savings over traditional storage tanks which also require active pressure and thermal regulation. The team will use a number of computational and experimental tools to develop a MOF structure suitable for this application.
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Last Updated Apr 18, 2025 EditorLoura Hall Related Terms
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Preparations for Next Moonwalk Simulations Underway (and Underwater)
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Kenshiro Oguri
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This project will investigate one of the key fundamental challenges associated with directed-energy light-sailing technology, similar to solar sails but powered by a laser beam pointed at the sail instead of by the sun. The effort will first mathematically model, then design, build, and test a prototype diffractive light sail. The three-dimensional, origami-inspired light sail could potentially unlock higher thrust, passive beam riding stability, and higher maneuverability via its ability to transform its shape.
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Last Updated Apr 18, 2025 EditorLoura Hall Related Terms
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By NASA
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Preparations for Next Moonwalk Simulations Underway (and Underwater)
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Ognjen Ilic
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This effort will aim to demonstrate the feasibility of directed-energy propulsion through a combination of computational simulations and prototype testing. The project will model the interactions between lightsail material and a laser beam that can be pointed at the sail to propel the spacecraft. The results of the modeling will be used to fabricate an optimized sail for testing with a 30W laser. A successful demonstration would pave the way for ultrafast spaceflight within and beyond the solar system.
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Last Updated Apr 18, 2025 EditorLoura Hall Related Terms
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