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Far-Flung Supernovae Shed Light on Dark Universe
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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 USH
On the night of Friday, May 16, something extraordinary lit up the skies over the American Southwest. A brilliant, fast-moving streak of light that captivated onlookers from Arizona to Colorado.
Witnesses in towns such as Safford, Fountain Hills, and Payson, as well as regions of New Mexico and Colorado, were left asking the same question: What exactly did we just see?
Speculation spread rapidly. Some suggested a Chinese rocket launch earlier that day could be responsible, possibly placing satellites into orbit. Others floated more exotic theories: perhaps STEVE, a rare atmospheric light phenomenon similar to the aurora borealis, or even a “light pillar,” formed when light reflects off high-altitude ice crystals.
Attempts to reach officials at Luke Air Force Base near Phoenix, Davis-Monthan Air Force Base in southern Arizona, and Kirtland Air Force Base in Albuquerque have so far yielded no response.
What if it wasn’t a rocket plume from a Chinese launch at all? What if something entirely different passed near our planet, like a comet or UFO, or perhaps it was a test of a space-based weapon or a directed-energy system?
Whatever it may have been, it remains a strange phenomenon, leaving many to wonder what truly streaked across the sky.
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By NASA
6 min read
NASA Observes First Visible-light Auroras at Mars
On March 15, 2024, near the peak of the current solar cycle, the Sun produced a solar flare and an accompanying coronal mass ejection (CME), a massive explosion of gas and magnetic energy that carries with it large amounts of solar energetic particles. This solar activity led to stunning auroras across the solar system, including at Mars, where NASA’s Perseverance Mars rover made history by detecting them for the first time from the surface of another planet.
The first visible-light image of green aurora on Mars (left), taken by the Mastcam-Z instrument on NASA’s Perseverance Mars rover. On the right is a comparison image of the night sky of Mars without aurora but featuring the Martian moon Deimos. The moonlit Martian night sky, lit up mostly by Mars’ nearer and larger moon Phobos (outside the frame) has a reddish-brown hue due to the dust in the atmosphere, so when green auroral light is added, the sky takes on a green-yellow tone, as seen in the left image. NASA/JPL-Caltech/ASU/MSSS/SSI “This exciting discovery opens up new possibilities for auroral research and confirms that auroras could be visible to future astronauts on Mars’ surface.” said Elise Knutsen, a postdoctoral researcher at the University of Oslo in Norway and lead author of the Science Advances study, which reported the detection.
Picking the right aurora
On Earth, auroras form when solar particles interact with the global magnetic field, funneling them to the poles where they collide with atmospheric gases and emit light. The most common color, green, is caused by excited oxygen atoms emitting light at a wavelength of 557.7 nanometers. For years, scientists have theorized that green light auroras could also exist on Mars but suggested they would be much fainter and harder to capture than the green auroras we see on Earth.
Due to the Red Planet’s lack of a global magnetic field, Mars has different types of auroras than those we have on Earth. One of these is solar energetic particle (SEP) auroras, which NASA’s MAVEN (Mars Atmosphere and Volatile EvolutioN) mission discovered in 2014. These occur when super-energetic particles from the Sun hit the Martian atmosphere, causing a reaction that makes the atmosphere glow across the whole night sky.
While MAVEN had observed SEP auroras in ultraviolet light from orbit, this phenomenon had never been observed in visible light from the ground. Since SEPs typically occur during solar storms, which increase during solar maximum, Knutsen and her team set their sights on capturing visible images and spectra of SEP aurora from Mars’ surface at the peak of the Sun’s current solar cycle.
Coordinating the picture-perfect moment
Through modeling, Knutsen and her team determined the optimal angle for the Perseverance rover’s SuperCam spectrometer and Mastcam-Z camera to successfully observe the SEP aurora in visible light. With this observation strategy in place, it all came down to the timing and understanding of CMEs.
“The trick was to pick a good CME, one that would accelerate and inject many charged particles into Mars’ atmosphere,” said Knutsen.
That is where the teams at NASA’s Moon to Mars (M2M) Space Weather Analysis Office and the Community Coordinated Modeling Center (CCMC), both located at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, came in. The M2M team provides real-time analysis of solar eruptions to the CCMC for initiating simulations of CMEs to determine if they might impact current NASA missions. When the simulations suggest potential impacts, the team sends out an alert.
At the University of California, Berkeley, space physicist Christina Lee received an alert from the M2M office about the March 15, 2024, CME. Lee, a member of the MAVEN mission team who serves as the space weather lead, determined there was a notable solar storm heading toward the Red Planet,which could arrive in a few days. She immediately issued the Mars Space Weather Alert Notification to currently operating Mars missions.
“This allows the science teams of Perseverance and MAVEN to anticipate impacts of interplanetary CMEs and the associated SEPs,” said Lee.
“When we saw the strength of this one,” Knutsen said, “we estimated it could trigger aurora bright enough for our instruments to detect.”
A few days later, the CME impacted Mars, providing a lightshow for the rover to capture, showing the aurora to be nearly uniform across the sky at an emission wavelength of exactly 557.7 nm. To confirm the presence of SEPs during the aurora observation, the team looked to MAVEN’s SEP instrument, which was additionally corroborated by data from ESA’s (European Space Agency) Mars Express mission. Data from both missions confirmed that the rover team had managed to successfully catch a glimpse of the phenomenon in the very narrow time window available.
“This was a fantastic example of cross-mission coordination. We all worked together quickly to facilitate this observation and are thrilled to have finally gotten a sneak peek of what astronauts will be able to see there some day,” said Shannon Curry, MAVEN principal investigator and research scientist at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder (CU Boulder).
The future of aurora on Mars
By coordinating the Perseverance observations with measurements from MAVEN’s SEP instrument, the teams could help each other determine that the observed 557.7 nm emission came from solar energetic particles. Since this is the same emission line as the green aurora on Earth, it is likely that future Martian astronauts would be able to see this type of aurora.
“Perseverance’s observations of the visible-light aurora confirm a new way to study these phenomena that’s complementary to what we can observe with our Mars orbiters,” said Katie Stack Morgan, acting project scientist for Perseverance at NASA’s Jet Propulsion Laboratory in Southern California. “A better understanding of auroras and the conditions around Mars that lead to their formation are especially important as we prepare to send human explorers there safely.”
On September 21, 2014, NASA’s MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft entered orbit around Mars. The mission has produced a wealth of data about how Mars’ atmosphere responds to the Sun and solar wind NASA/JPL-Caltech More About Perseverance and MAVEN
The Mars 2020 Perseverance mission is part of NASA’s Mars Exploration Program portfolio and NASA’s Moon to Mars exploration approach, which includes Artemis missions to the Moon that will help prepare for human exploration of the Red Planet. NASA’s Jet Propulsion Laboratory, which is managed for the agency by Caltech, built and manages operations of the Perseverance rover.
The MAVEN mission, also part of NASA’s Mars Exploration Program portfolio, is led by LASP at CU Boulder. It’s managed by NASA’s Goddard Space Flight Center and was built and operated by Lockheed Martin Space, with navigation and network support from NASA’s JPL.
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By Willow Reed
Laboratory for Atmospheric and Space Physics (LASP), University of Colorado Boulder
Media Contact:
Karen Fox / Molly Wasser
Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
Nancy N. Jones
NASA’s Goddard Space Flight Center, Greenbelt, Md.
DC Agle
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-9011
agle@jpl.nasa.gov
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Last Updated May 14, 2025 Related Terms
Mars Goddard Space Flight Center MAVEN (Mars Atmosphere and Volatile EvolutioN) View the full article
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By NASA
Explore This Section Science Science Activation Take a Tour of the Cosmos with… Overview Learning Resources Science Activation Teams SME Map Opportunities More Science Activation Stories Citizen Science 4 min read
Take a Tour of the Cosmos with New Interactives from NASA’s Universe of Learning
Ready for a tour of the cosmos? NASA’s Universe of Learning has released a new, dynamic way for lifelong learners to explore NASA’s breathtaking images of the universe—ViewSpace interactive Image Tours. ViewSpace has an established track record of providing museums, science centers, libraries, and other informal learning environments with free, web-based videos and digital interactives—like its interactive Image Sliders. These new Image Tours are another unique experience from NASA’s Universe of Learning, created through a collaboration between scientists that operate NASA telescopes and experts well-versed in the most modern methods of learning. Hands-on, self-directed learning resources like these have long been valued by informal learning sites as effective means for engaging and intriguing users with the latest discoveries from NASA’s space telescope missions—while encouraging lifelong learners to continue their passionate exploration of the stars, galaxies, and distant worlds.
With these new ViewSpace Image Tours, visitors can take breathtaking journeys through space images that contain many exciting stories. The “Center of the Milky Way Galaxy” Tour, for example, uses breathtaking images from NASA’s Hubble, Spitzer, and Chandra X-ray telescopes and includes eleven Tour Stops, where users can interact with areas like “the Brick”—a dense, dark cloud of hydrogen molecules imaged by Spitzer. Another Tour Stop zooms toward the supermassive black hole, Sagittarius A*, offering a dramatic visual journey to the galaxy’s core.
In other tours, like the “Herbig-Haro 46/47” Tour, learners can navigate through points of interest in an observation from a single telescope mission. In this case, NASA’s James Webb Space Telescope provides the backdrop where lifelong learners can explore superheated jets of gas and dust being ejected at tremendous speeds from a pair of young, forming stars. The power of Webb turns up unexpected details in the background, like a noteworthy distant galaxy famous for its uncanny resemblance to a question mark. Each Interactive Image Tour allows people to examine unique features through videos, images, or graphical overlays to identify how those features have formed in ways that static images alone can’t convey.
These tours, which include detailed visual descriptions for each Tour Stop, illuminate the science behind the beauty, allowing learners of all ages to develop a greater understanding of and excitement for space science, deepening their engagement with astronomy, regardless of their prior experience. Check out the About the Interactives page on the ViewSpace website for a detailed overview of how to use the Image Tours.
ViewSpace currently offers three Image Tours, and the collection will continue growing:
Center of the Milky Way Galaxy:
Peer through cosmic dust and uncover areas of intense activity near the Milky Way’s core, featuring imagery from the Hubble Space Telescope, Spitzer Space Telescope, and the Chandra X-ray Observatory.
Herbig-Haro 46/47:
Witness how a tightly bound pair of young stars shapes their nebula through ejections of gas and dust in an image from the James Webb Space Telescope.
The Whirlpool Galaxy:
Explore the iconic swirling arms and glowing core of a stunning spiral galaxy, with insights into star formation, galaxy structure, and more in a Hubble Space Telescope image.
“The Image Tours are beautiful, dramatic, informational, and easy to use,” explained Sari Custer, Chief of Science and Curiosity at Arizona Science Center. “I’m excited to implement them in my museum not only because of the incredible images and user-friendly features, but also for the opportunity to excite and ignite the public’s curiosity about space.”
NASA’s Universe of Learning is supported by NASA under cooperative agreement award number NNX16AC65A and is part of NASA’s Science Activation Portfolio. Learn more about how Science Activation connects NASA science experts, real content, and experiences with community leaders to do science in ways that activate minds and promote deeper understanding of our world and beyond: https://science.nasa.gov/learn/about-science-activation/
Select views from various Image Tours. Clockwise from top left: The Whirlpool Galaxy, Center of the Milky Way Galaxy, Herbig-Haro 46/47, detail view in the Center of the Milky Way Galaxy. Share
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Last Updated May 13, 2025 Editor NASA Science Editorial Team Related Terms
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