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By NASA
A funky effect Einstein predicted, known as gravitational lensing — when a foreground galaxy magnifies more distant galaxies behind it — will soon become common when NASA’s Nancy Grace Roman Space Telescope begins science operations in 2027 and produces vast surveys of the cosmos.
This image shows a simulated observation from NASA’s Nancy Grace Roman Space Telescope with an overlay of its Wide Field Instrument’s field of view. More than 20 gravitational lenses, with examples shown at left and right, are expected to pop out in every one of Roman’s vast observations. A journal paper led by Bryce Wedig, a graduate student at Washington University in St. Louis, Missouri, estimates that of those Roman detects, about 500 from the telescope’s High-Latitude Wide-Area Survey will be suitable for dark matter studies. By examining such a large population of gravitational lenses, the researchers hope to learn a lot more about the mysterious nature of dark matter.Credit: NASA, Bryce Wedig (Washington University), Tansu Daylan (Washington University), Joseph DePasquale (STScI) A particular subset of gravitational lenses, known as strong lenses, is the focus of a new paper published in the Astrophysical Journal led by Bryce Wedig, a graduate student at Washington University in St. Louis. The research team has calculated that over 160,000 gravitational lenses, including hundreds suitable for this study, are expected to pop up in Roman’s vast images. Each Roman image will be 200 times larger than infrared snapshots from NASA’s Hubble Space Telescope, and its upcoming “wealth” of lenses will vastly outpace the hundreds studied by Hubble to date.
Roman will conduct three core surveys, providing expansive views of the universe. This science team’s work is based on a previous version of Roman’s now fully defined High-Latitude Wide-Area Survey. The researchers are working on a follow-up paper that will align with the final survey’s specifications to fully support the research community.
“The current sample size of these objects from other telescopes is fairly small because we’re relying on two galaxies to be lined up nearly perfectly along our line of sight,” Wedig said. “Other telescopes are either limited to a smaller field of view or less precise observations, making gravitational lenses harder to detect.”
Gravitational lenses are made up of at least two cosmic objects. In some cases, a single foreground galaxy has enough mass to act like a lens, magnifying a galaxy that is almost perfectly behind it. Light from the background galaxy curves around the foreground galaxy along more than one path, appearing in observations as warped arcs and crescents. Of the 160,000 lensed galaxies Roman may identify, the team expects to narrow that down to about 500 that are suitable for studying the structure of dark matter at scales smaller than those galaxies.
“Roman will not only significantly increase our sample size — its sharp, high-resolution images will also allow us to discover gravitational lenses that appear smaller on the sky,” said Tansu Daylan, the principal investigator of the science team conducting this research program. Daylan is an assistant professor and a faculty fellow at the McDonnell Center for the Space Sciences at Washington University in St. Louis. “Ultimately, both the alignment and the brightness of the background galaxies need to meet a certain threshold so we can characterize the dark matter within the foreground galaxies.”
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This video shows how a background galaxy’s light is lensed or magnified by a massive foreground galaxy, seen at center, before reaching NASA’s Roman Space Telescope. Light from the background galaxy is distorted, curving around the foreground galaxy and appearing more than once as warped arcs and crescents. Researchers studying these objects, known as gravitational lenses, can better characterize the mass of the foreground galaxy, which offers clues about the particle nature of dark matter.Credit: NASA, Joseph Olmsted (STScI) What Is Dark Matter?
Not all mass in galaxies is made up of objects we can see, like star clusters. A significant fraction of a galaxy’s mass is made up of dark matter, so called because it doesn’t emit, reflect, or absorb light. Dark matter does, however, possess mass, and like anything else with mass, it can cause gravitational lensing.
When the gravity of a foreground galaxy bends the path of a background galaxy’s light, its light is routed onto multiple paths. “This effect produces multiple images of the background galaxy that are magnified and distorted differently,” Daylan said. These “duplicates” are a huge advantage for researchers — they allow multiple measurements of the lensing galaxy’s mass distribution, ensuring that the resulting measurement is far more precise.
Roman’s 300-megapixel camera, known as its Wide Field Instrument, will allow researchers to accurately determine the bending of the background galaxies’ light by as little as 50 milliarcseconds, which is like measuring the diameter of a human hair from the distance of more than two and a half American football fields or soccer pitches.
The amount of gravitational lensing that the background light experiences depends on the intervening mass. Less massive clumps of dark matter cause smaller distortions. As a result, if researchers are able to measure tinier amounts of bending, they can detect and characterize smaller, less massive dark matter structures — the types of structures that gradually merged over time to build up the galaxies we see today.
With Roman, the team will accumulate overwhelming statistics about the size and structures of early galaxies. “Finding gravitational lenses and being able to detect clumps of dark matter in them is a game of tiny odds. With Roman, we can cast a wide net and expect to get lucky often,” Wedig said. “We won’t see dark matter in the images — it’s invisible — but we can measure its effects.”
“Ultimately, the question we’re trying to address is: What particle or particles constitute dark matter?” Daylan added. “While some properties of dark matter are known, we essentially have no idea what makes up dark matter. Roman will help us to distinguish how dark matter is distributed on small scales and, hence, its particle nature.”
Preparations Continue
Before Roman launches, the team will also search for more candidates in observations from ESA’s (the European Space Agency’s) Euclid mission and the upcoming ground-based Vera C. Rubin Observatory in Chile, which will begin its full-scale operations in a few weeks. Once Roman’s infrared images are in hand, the researchers will combine them with complementary visible light images from Euclid, Rubin, and Hubble to maximize what’s known about these galaxies.
“We will push the limits of what we can observe, and use every gravitational lens we detect with Roman to pin down the particle nature of dark matter,” Daylan said.
The Nancy Grace Roman Space Telescope is managed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, with participation by NASA’s Jet Propulsion Laboratory in Southern California; Caltech/IPAC in Pasadena, California; the Space Telescope Science Institute in Baltimore; and a science team comprising scientists from various research institutions. The primary industrial partners are BAE Systems, Inc. in Boulder, Colorado; L3Harris Technologies in Melbourne, Florida; and Teledyne Scientific & Imaging in Thousand Oaks, California.
By Claire Blome
Space Telescope Science Institute, Baltimore, Md.
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Last Updated Jun 12, 2025 EditorAshley BalzerContactAshley Balzerashley.m.balzer@nasa.govLocationNASA Goddard Space Flight Center Related Terms
Nancy Grace Roman Space Telescope Astrophysics Dark Matter Galaxies Galaxies, Stars, & Black Holes Galaxies, Stars, & Black Holes Research The Universe Explore More
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By NASA
6 min read
NASA’s Dragonfly Mission Sets Sights on Titan’s Mysteries
When it descends through the thick golden haze on Saturn’s moon Titan, NASA’s Dragonfly rotorcraft will find eerily familiar terrain. Dunes wrap around Titan’s equator. Clouds drift across its skies. Rain drizzles. Rivers flow, forming canyons, lakes and seas.
Artist’s concept of NASA’s Dragonfly on the surface of Saturn’s moon Titan. The car-sized rotorcraft will be equipped to characterize the habitability of Titan’s environment, investigate the progression of prebiotic chemistry in an environment where carbon-rich material and liquid water may have mixed for an extended period, and even search for chemical indications of whether water-based or hydrocarbon-based life once existed on Titan. NASA/Johns Hopkins APL/Steve Gribben But not everything is as familiar as it seems. At minus 292 degrees Fahrenheit, the dune sands aren’t silicate grains but organic material. The rivers, lakes and seas hold liquid methane and ethane, not water. Titan is a frigid world laden with organic molecules.
Yet Dragonfly, a car-sized rotorcraft set to launch no earlier than 2028, will explore this frigid world to potentially answer one of science’s biggest questions: How did life begin?
Seeking answers about life in a place where it likely can’t survive seems odd. But that’s precisely the point.
“Dragonfly isn’t a mission to detect life — it’s a mission to investigate the chemistry that came before biology here on Earth,” said Zibi Turtle, principal investigator for Dragonfly and a planetary scientist at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland. “On Titan, we can explore the chemical processes that may have led to life on Earth without life complicating the picture.”
On Earth, life has reshaped nearly everything, burying its chemical forebears beneath eons of evolution. Even today’s microbes rely on a slew of reactions to keep squirming.
“You need to have gone from simple to complex chemistry before jumping to biology, but we don’t know all the steps,” Turtle said. “Titan allows us to uncover some of them.”
Titan is an untouched chemical laboratory where all the ingredients for known life — organics, liquid water and an energy source — have interacted in the past. What Dragonfly uncovers will illuminate a past since erased on Earth and refine our understanding of habitability and whether the chemistry that sparked life here is a universal rule — or a wonderous cosmic fluke.
Before NASA’s Cassini-Huygens mission, researchers didn’t know just how rich Titan is in organic molecules. The mission’s data, combined with laboratory experiments, revealed a molecular smorgasbord — ethane, propane, acetylene, acetone, vinyl cyanide, benzene, cyanogen, and more.
These molecules fall to the surface, forming thick deposits on Titan’s ice bedrock. Scientists believe life-related chemistry could start there — if given some liquid water, such as from an asteroid impact.
Enter Selk crater, a 50-mile-wide impact site. It’s a key Dragonfly destination, not only because it’s covered in organics, but because it may have had liquid water for an extended time.
Selk crater, a 50-mile-wide impact site highlighted on this infrared image of Titan, is a key Dragonfly destination. Landing near Selk, Dragonfly will explore various sites, analyzing the surface chemistry to investigate the frozen remains of what could have been prebiotic chemistry in action. NASA/JPL-Caltech/University of Nantes/University of Arizona The impact that formed Selk melted the icy bedrock, creating a temporary pool that could have remained liquid for hundreds to thousands of years under an insulating ice layer, like winter ponds on Earth. If a natural antifreeze like ammonia were mixed in, the pool could have remained unfrozen even longer, blending water with organics and the impactor’s silicon, phosphorus, sulfur and iron to form a primordial soup.
“It’s essentially a long-running chemical experiment,” said Sarah Hörst, an atmospheric chemist at Johns Hopkins University and co-investigator on Dragonfly’s science team. “That’s why Titan is exciting. It’s a natural version of our origin-of-life experiments — except it’s been running much longer and on a planetary scale.”
For decades, scientists have simulated Earth’s early conditions, mixing water with simple organics to create a “prebiotic soup” and jumpstarting reactions with an electrical shock. The problem is time. Most tests last weeks, maybe months or years.
The melt pools at Selk crater, however, possibly lasted tens of thousands of years. Still shorter than the hundreds of millions of years it took life to emerge on Earth, but potentially enough time for critical chemistry to occur.
“We don’t know if Earth life took so long because conditions had to stabilize or because the chemistry itself needed time,” Hörst said. “But models show that if you toss Titan’s organics into water, tens of thousands of years is plenty of time for chemistry to happen.”
Dragonfly will test that theory. Landing near Selk, it will fly from site to site, analyzing the surface chemistry to investigate the frozen remains of what could have been prebiotic chemistry in action.
Morgan Cable, a research scientist at NASA’s Jet Propulsion Laboratory in Southern California and co-investigator on Dragonfly, is particularly excited about the Dragonfly Mass Spectrometer (DraMS) instrument. Developed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, with a key subsystem provided by the CNES (Centre National d’Etudes Spatiales), DraMS will search for indicators of complex chemistry.
“We’re not looking for exact molecules, but patterns that suggest complexity,” Cable said. On Earth, for example, amino acids — fundamental to proteins — appear in specific patterns. A world without life would mainly manufacture the simplest amino acids and form fewer complex ones.
Generally, Titan isn’t regarded as habitable; it’s too cold for the chemistry of life as we know it to occur, and there’s is no liquid water on the surface, where the organics and likely energy sources exist.
Still, scientists have assumed that if a place has life’s ingredients and enough time, complex chemistry — and eventually life — should emerge. If Titan proves otherwise, it may mean we’ve misunderstood something about life’s start and it may be rarer than we thought.
“We won’t know how easy or difficult it is for these chemical steps to occur if we don’t go, so we need to go and look,” Cable said. “That’s the fun thing about going to a world like Titan. We’re like detectives with our magnifying glasses, looking at everything and wondering what this is.”
Dragonfly is being designed and built under the direction of the Johns Hopkins Applied Physics Laboratory (APL), which manages the mission for NASA. The team includes key partners at NASA’s Goddard Space Flight Center and NASA’s Jet Propulsion Laboratory. Dragonfly is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate at NASA Headquarters in Washington.
For more information on Dragonfly, visit:
https://science.nasa.gov/mission/dragonfly/
By Jeremy Rehm
Johns Hopkins Applied Physics Laboratory, Laurel, Md.
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Explore Webb Webb News Latest News Latest Images Webb’s Blog Awards X (offsite – login reqd) Instagram (offsite – login reqd) Facebook (offsite- login reqd) Youtube (offsite) Overview About Who is James Webb? Fact Sheet Impacts+Benefits FAQ Science Overview and Goals Early Universe Galaxies Over Time Star Lifecycle Other Worlds Observatory Overview Launch Deployment Orbit Mirrors Sunshield Instrument: NIRCam Instrument: MIRI Instrument: NIRSpec Instrument: FGS/NIRISS Optical Telescope Element Backplane Spacecraft Bus Instrument Module Multimedia About Webb Images Images Videos What is Webb Observing? 3d Webb in 3d Solar System Podcasts Webb Image Sonifications Team International Team People Of Webb More For the Media For Scientists For Educators For Fun/Learning 5 Min Read NASA’s Webb Reveals New Details, Mysteries in Jupiter’s Aurora
NASA’s James Webb Space Telescope has captured new details of the auroras on our solar system’s largest planet. The dancing lights observed on Jupiter are hundreds of times brighter than those seen on Earth. Full image below. Credits:
NASA, ESA, CSA, Jonathan Nichols (University of Leicester), Mahdi Zamani (ESA/Webb) NASA’s James Webb Space Telescope has captured new details of the auroras on our solar system’s largest planet. The dancing lights observed on Jupiter are hundreds of times brighter than those seen on Earth. With Webb’s advanced sensitivity, astronomers have studied the phenomena to better understand Jupiter’s magnetosphere.
Auroras are created when high-energy particles enter a planet’s atmosphere near its magnetic poles and collide with atoms or molecules of gas. On Earth these are known as the Northern and Southern Lights. Not only are the auroras on Jupiter huge in size, they are also hundreds of times more energetic than those in Earth’s atmosphere. Earth’s auroras are caused by solar storms — when charged particles from the Sun rain down on the upper atmosphere, energize gases, and cause them to glow in shades of red, green and purple.
Image A: Close-up Observations of Auroras on Jupiter
NASA’s James Webb Space Telescope has captured new details of the auroras on our solar system’s largest planet. The dancing lights observed on Jupiter are hundreds of times brighter than those seen on Earth.
These observations of Jupiter’s auroras, taken at a wavelength of 3.36 microns (F335M) were captured with Webb’s NIRCam (Near-Infrared Camera) on Dec. 25, 2023. Scientists found that the emission from trihydrogen cation, known as H3+, is far more variable than previously believed. H3+ is created by the impact of high energy electrons on molecular hydrogen. Because this emission shines brightly in the infrared, Webb’s instruments are well equipped to observe it. NASA, ESA, CSA, Jonathan Nichols (University of Leicester), Mahdi Zamani (ESA/Webb) Jupiter has an additional source for its auroras: The strong magnetic field of the gas giant grabs charged particles from its surroundings. This includes not only the charged particles within the solar wind but also the particles thrown into space by its orbiting moon Io, known for its numerous and large volcanoes. Io’s volcanoes spew particles that escape the moon’s gravity and orbit Jupiter. A barrage of charged particles unleashed by the Sun also reaches the planet. Jupiter’s large and powerful magnetic field captures all of the charged particles and accelerates them to tremendous speeds. These speedy particles slam into the planet’s atmosphere at high energies, which excites the gas and causes it to glow.
Image B: Pullout of Aurora Observations on Jupiter (NIRCam Image)
These observations of Jupiter’s auroras (shown on the left of the above image) at 3.35 microns (F335M) were captured with NASA’s James Webb Space Telescope’s NIRCam (Near-Infrared Camera) on Dec. 25, 2023. Scientists found that the emission from trihydrogen cation, known as H3+, is far more variable than previously believed. H3+ is created by the impact of high energy electrons on molecular hydrogen. Because this emission shines brightly in the infrared, Webb’s instruments are well equipped to observe it. The image on the right shows the planet Jupiter to indicate the location of the observed auroras, which was originally published in 2023. NASA, ESA, CSA, STScI, Ricardo Hueso (UPV), Imke de Pater (UC Berkeley), Thierry Fouchet (Observatory of Paris), Leigh Fletcher (University of Leicester), Michael H. Wong (UC Berkeley), Joseph DePasquale (STScI), Jonathan Nichols (University of Leicester), Mahdi Zamani (ESA/Webb) Now, Webb’s unique capabilities are providing new insights into the auroras on Jupiter. The telescope’s sensitivity allows astronomers to capture fast-varying auroral features. New data was captured with Webb’s NIRCam (Near-Infrared Camera) Dec. 25, 2023, by a team of scientists led by Jonathan Nichols from the University of Leicester in the United Kingdom.
“What a Christmas present it was – it just blew me away!” shared Nichols. “We wanted to see how quickly the auroras change, expecting them to fade in and out ponderously, perhaps over a quarter of an hour or so. Instead, we observed the whole auroral region fizzing and popping with light, sometimes varying by the second.”
In particular, the team studied emission from the trihydrogen cation (H3+), which can be created in auroras. They found that this emission is far more variable than previously believed. The observations will help develop scientists’ understanding of how Jupiter’s upper atmosphere is heated and cooled.
The team also uncovered some unexplained observations in their data.
“What made these observations even more special is that we also took pictures simultaneously in the ultraviolet with NASA’s Hubble Space Telescope,” added Nichols. “Bizarrely, the brightest light observed by Webb had no real counterpart in Hubble’s pictures. This has left us scratching our heads. In order to cause the combination of brightness seen by both Webb and Hubble, we need to have a combination of high quantities of very low-energy particles hitting the atmosphere, which was previously thought to be impossible. We still don’t understand how this happens.”
Video: Webb Captures Jupiter’s Aurora
NASA’s James Webb Space Telescope has captured a spectacular light show on Jupiter — an enormous display of auroras unlike anything seen on Earth. These infrared observations reveal unexpected activity in Jupiter’s atmosphere, challenging what scientists thought they knew about the planet’s magnetic field and particle interactions. Combined with ultraviolet data from Hubble, the results have raised surprising new questions about Jupiter’s extreme environment.
Producer: Paul Morris. Writer: Thaddeus Cesari. Narrator: Professor Jonathan Nichols. Images: NASA, ESA, CSA, STScI. Music Credit: “Zero Gravity” by Brice Davoli [SACEM] via Koka Media [SACEM], Universal Production Music France [SACEM], and Universal Production Music. The team now plans to study this discrepancy between the Hubble and Webb data and to explore the wider implications for Jupiter’s atmosphere and space environment. They also intend to follow up this research with more Webb observations, which they can compare with data from NASA’s Juno spacecraft to better explore the cause of the enigmatic bright emission.
These results were published today in the journal Nature Communications.
The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
To learn more about Webb, visit:
https://science.nasa.gov/webb
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NASA’s Goddard Space Flight Center, Greenbelt, Md.
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ESA/Webb, Baltimore, Md.
Christine Pulliam – cpulliam@stsci.edu
Space Telescope Science Institute, Baltimore, Md.
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By European Space Agency
The NASA/ESA/CSA James Webb Space Telescope has captured new details of the auroras on our Solar System’s largest planet. The dancing lights observed on Jupiter are hundreds of times brighter than those seen on Earth. With Webb’s advanced sensitivity, astronomers have studied the phenomena to better understand Jupiter’s magnetosphere.
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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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