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NASA’s Roman to Use Rare Events to Calculate Expansion Rate of Universe
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By European Space Agency
Using the unique infrared sensitivity of the NASA/ESA/CSA James Webb Space Telescope, researchers can examine ancient galaxies to probe secrets of the early Universe. Now, an international team of astronomers has identified bright hydrogen emission from a galaxy in an unexpectedly early time in the Universe’s history. The surprise finding is challenging researchers to explain how this light could have pierced the thick fog of neutral hydrogen that filled space at that time.
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By NASA
Explore This Section Webb News Latest News Latest Images Blog (offsite) 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 Sees Galaxy Mysteriously Clearing Fog of Early Universe
The incredibly distant galaxy JADES-GS-z13-1, observed just 330 million years after the big bang, was initially discovered with deep imaging from NASA’s James Webb Space Telescope’s NIRCam (Near-Infrared Camera). Full image below. Credits:
NASA, ESA, CSA, JADES Collaboration, J. Witstok (University of Cambridge/University of Copenhagen), P. Jakobsen (University of Copenhagen), A. Pagan (STScI), M. Zamani (ESA/Webb) Using the unique infrared sensitivity of NASA’s James Webb Space Telescope, researchers can examine ancient galaxies to probe secrets of the early universe. Now, an international team of astronomers has identified bright hydrogen emission from a galaxy in an unexpectedly early time in the universe’s history. The surprise finding is challenging researchers to explain how this light could have pierced the thick fog of neutral hydrogen that filled space at that time.
The Webb telescope discovered the incredibly distant galaxy JADES-GS-z13-1, observed to exist just 330 million years after the big bang, in images taken by Webb’s NIRCam (Near-Infrared Camera) as part of the James Webb Space Telescope Advanced Deep Extragalactic Survey (JADES). Researchers used the galaxy’s brightness in different infrared filters to estimate its redshift, which measures a galaxy’s distance from Earth based on how its light has been stretched out during its journey through expanding space.
Image A: JADES-GS-z13-1 in the GOODS-S field (NIRCam Image)
The incredibly distant galaxy JADES-GS-z13-1, observed just 330 million years after the big bang, was initially discovered with deep imaging from NASA’s James Webb Space Telescope’s NIRCam (Near-Infrared Camera). Now, an international team of astronomers definitively has identified powerful hydrogen emission from this galaxy at an unexpectedly early period in the universe’s history. JADES-GS-z-13 has a redshift (z) of 13, which is an indication of its age and distance. NASA, ESA, CSA, JADES Collaboration, J. Witstok (University of Cambridge/University of Copenhagen), P. Jakobsen (University of Copenhagen), A. Pagan (STScI), M. Zamani (ESA/Webb) Image B: JADES-GS-z13-1 (NIRCam Close-Up)
This image shows the galaxy JADES GS-z13-1 (the red dot at center), imaged with NASA’s James Webb Space Telescope’s NIRCam (Near-Infrared Camera) as part of the JWST Advanced Deep Extragalactic Survey (JADES) program. These data from NIRCam allowed researchers to identify GS-z13-1 as an incredibly distant galaxy, and to put an estimate on its redshift value. Webb’s unique infrared sensitivity is necessary to observe galaxies at this extreme distance, whose light has been shifted into infrared wavelengths during its long journey across the cosmos. NASA, ESA, CSA, JADES Collaboration, J. Witstok (University of Cambridge/University of Copenhagen), P. Jakobsen (University of Copenhagen), M. Zamani (ESA/Webb) The NIRCam imaging yielded an initial redshift estimate of 12.9. Seeking to confirm its extreme redshift, an international team lead by Joris Witstok of the University of Cambridge in the United Kingdom, as well as the Cosmic Dawn Center and the University of Copenhagen in Denmark, then observed the galaxy using Webb’s Near-Infrared Spectrograph instrument.
In the resulting spectrum, the redshift was confirmed to be 13.0. This equates to a galaxy seen just 330 million years after the big bang, a small fraction of the universe’s present age of 13.8 billion years old. But an unexpected feature stood out as well: one specific, distinctly bright wavelength of light, known as Lyman-alpha emission, radiated by hydrogen atoms. This emission was far stronger than astronomers thought possible at this early stage in the universe’s development.
“The early universe was bathed in a thick fog of neutral hydrogen,” explained Roberto Maiolino, a team member from the University of Cambridge and University College London. “Most of this haze was lifted in a process called reionization, which was completed about one billion years after the big bang. GS-z13-1 is seen when the universe was only 330 million years old, yet it shows a surprisingly clear, telltale signature of Lyman-alpha emission that can only be seen once the surrounding fog has fully lifted. This result was totally unexpected by theories of early galaxy formation and has caught astronomers by surprise.”
Image C: JADES-GS-z13-1 Spectrum Graphic
NASA’s James Webb Space Telescope has detected unexpected light from a distant galaxy. The galaxy JADES-GS-z13-1, observed just 330 million years after the big bang (corresponding to a redshift of z=13.05), shows bright emission from hydrogen known as Lyman-alpha emission. This is surprising because that emission should have been absorbed by a dense fog of neutral hydrogen that suffused the early universe. NASA, ESA, CSA, J. Witstok (University of Cambridge, University of Copenhagen), J. Olmsted (STScI) Before and during the era of reionization, the immense amounts of neutral hydrogen fog surrounding galaxies blocked any energetic ultraviolet light they emitted, much like the filtering effect of colored glass. Until enough stars had formed and were able to ionize the hydrogen gas, no such light — including Lyman-alpha emission — could escape from these fledgling galaxies to reach Earth. The confirmation of Lyman-alpha radiation from this galaxy, therefore, has great implications for our understanding of the early universe.
“We really shouldn’t have found a galaxy like this, given our understanding of the way the universe has evolved,” said Kevin Hainline, a team member from the University of Arizona. “We could think of the early universe as shrouded with a thick fog that would make it exceedingly difficult to find even powerful lighthouses peeking through, yet here we see the beam of light from this galaxy piercing the veil. This fascinating emission line has huge ramifications for how and when the universe reionized.”
The source of the Lyman-alpha radiation from this galaxy is not yet known, but it may include the first light from the earliest generation of stars to form in the universe.
“The large bubble of ionized hydrogen surrounding this galaxy might have been created by a peculiar population of stars — much more massive, hotter, and more luminous than stars formed at later epochs, and possibly representative of the first generation of stars,” said Witstok. A powerful active galactic nucleus, driven by one of the first supermassive black holes, is another possibility identified by the team.
This research was published Wednesday in the journal Nature.
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).
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Laura Betz – laura.e.betz@nasa.gov
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Christine Pulliam – cpulliam@stsci.edu
Space Telescope Science Institute, Baltimore, Md.
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Last Updated Mar 25, 2025 Editor Marty McCoy Contact Laura Betz laura.e.betz@nasa.gov Related Terms
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By NASA
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Preparations for Next Moonwalk Simulations Underway (and Underwater)
This image shows about 1.5% of Euclid’s Deep Field South, one of three regions of the sky that the telescope will observe for more than 40 weeks over the course of its prime mission, spotting faint and distant galaxies. One galaxy cluster near the center is located almost 6 billion light-years away from Earth. ESA/Euclid/Euclid Consortium/NASA; image processing by J.-C. Cuillandre, E. Bertin, G. An-selmi With contributions from NASA, the mission is looking back into the universe’s history to understand how the universe’s expansion has changed.
The Euclid mission — led by ESA (European Space Agency) with contributions from NASA — aims to find out why our universe is expanding at an accelerating rate. Astronomers use the term “dark energy” to refer to the unknown cause of this phenomenon, and Euclid will take images of billions of galaxies to learn more about it. A portion of the mission’s data was released to the public by ESA released on Wednesday, March 19.
This new data has been analyzed by mission scientists and provides a glimpse of Euclid’s progress. Deemed a “quick” data release, this batch focuses on select areas of the sky to demonstrate what can be expected in the larger data releases to come and to allow scientists to sharpen their data analysis tools in preparation.
The data release contains observations of Euclid’s three “deep fields,” or areas of the sky where the space telescope will eventually make its farthest observations of the universe. Featuring one week’s worth of viewing, the Euclid images contain 26 million galaxies, the most distant being over 10.5 billion light-years away. Launched in July 2023, the space telescope is expected to observe more than 1.5 billion galaxies during its six-year prime mission.
The entirety of the Euclid mission’s Deep Field South region is shown here. It is about 28.1 square degrees on the sky. Euclid will observe this and two other deep field regions for a total of about 40 weeks during its 6-year primary mission. ESA/Euclid/Euclid Consortium/NASA; image processing by J.-C. Cuillandre, E. Bertin, G. An-selmi By the end of that prime mission, Euclid will have observed the deep fields for a total of about 40 weeks in order to gradually collect more light, revealing fainter and more distant galaxies. This approach is akin to keeping a camera shutter open to photograph a subject in low light.
The first deep field observations, taken by NASA’s Hubble Space Telescope in 1995, famously revealed the existence of many more galaxies in the universe than expected. Euclid’s ultimate goal is not to discover new galaxies but to use observations of them to investigate how dark energy’s influence has changed over the course of the universe’s history.
In particular, scientists want to know how much the rate of expansion has increased or slowed down over time. Whatever the answer, that information would provide new clues about the fundamental nature of this phenomenon. NASA’s Nancy Grace Roman Space Telescope, set to launch by 2027, will also observe large sections of the sky in order to study dark energy, complementing Euclid’s observations.
The location of the Euclid deep fields are shown marked in yellow on this all-sky view from ESA’s Gaia and Planck missions. The bright horizontal band is the plane of our Milky Way galaxy. Euclid’s Deep Field South is at bottom left.ESA/Euclid/Euclid Consortium/NASA; ESA/Gaia/DPAC; ESA/Planck Collaboration Looking Back in Time
To study dark energy’s effect throughout cosmic history, astronomers will use Euclid to create detailed, 3D maps of all the stuff in the universe. With those maps, they want to measure how quickly dark energy is causing galaxies and big clumps of matter to move away from one another. They also want to measure that rate of expansion at different points in the past. This is possible because light from distant objects takes time to travel across space. When astronomers look at distant galaxies, they see what those objects looked like in the past.
For example, an object 100 light-years away looks the way it did 100 years ago. It’s like receiving a letter that took 100 years to be delivered and thus contains information from when it was written. By creating a map of objects at a range of distances, scientists can see how the universe has changed over time, including how dark energy’s influence may have varied.
But stars, galaxies, and all the “normal” matter that emits and reflects light is only about one-fifth of all the matter in the universe. The rest is called “dark matter” — a material that neither emits nor reflects light. To measure dark energy’s influence on the universe, astronomers need to include dark matter in their maps.
Bending and Warping
Although dark matter is invisible, its influence can be measured through something called gravitational lensing. The mass of both normal and dark matter creates curves in space, and light traveling toward Earth bends or warps as it encounters those curves. In fact, the light from a distant galaxy can bend so much that it forms an arc, a full circle (called an Einstein ring), or even multiple images of the same galaxy, almost as though the light has passed through a glass lens.
In most cases, gravitational lensing warps the apparent shape of a galaxy so subtly that researchers need special tools and computer software to see it. Spotting those subtle changes across billions of galaxies enables scientists to do two things: create a detailed map of the presence of dark matter and observe how dark energy influenced it over cosmic history.
It is only with a very large sample of galaxies that researchers can be confident they are seeing the effects of dark matter. The newly released Euclid data covers 63 square degrees of the sky, an area equivalent to an array of 300 full Moons. To date, Euclid has observed about 2,000 square degrees, which is approximately 14% of its total survey area of 14,000 square degrees. By the end of its mission, Euclid will have observed a third of the entire sky.
The dataset released this month is described in several preprint papers available today. The mission’s first cosmology data will be released in October 2026. Data accumulated over additional, multiple passes of the deep field locations will also be included in the 2026 release.
More About Euclid
Euclid is a European mission, built and operated by ESA, with contributions from NASA. The Euclid Consortium — consisting of more than 2,000 scientists from 300 institutes in 15 European countries, the United States, Canada, and Japan — is responsible for providing the scientific instruments and scientific data analysis. ESA selected Thales Alenia Space as prime contractor for the construction of the satellite and its service module, with Airbus Defence and Space chosen to develop the payload module, including the telescope. Euclid is a medium-class mission in ESA’s Cosmic Vision Programme.
Three NASA-supported science teams contribute to the Euclid mission. In addition to designing and fabricating the sensor-chip electronics for Euclid’s Near Infrared Spectrometer and Photometer (NISP) instrument, JPL led the procurement and delivery of the NISP detectors as well. Those detectors, along with the sensor chip electronics, were tested at NASA’s Detector Characterization Lab at Goddard Space Flight Center in Greenbelt, Maryland. The Euclid NASA Science Center at IPAC (ENSCI), at Caltech in Pasadena, California, supports U.S.-based science investigations, and science data is archived at the NASA / IPAC Infrared Science Archive (IRSA). JPL is a division of Caltech.
For more information about Euclid go to:
science.nasa.gov/mission/euclid/
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Last Updated Mar 19, 2025 Related Terms
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By NASA
NASA’s SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer) observatory and PUNCH (Polarimeter to Unify the Corona and Heliosphere) satellites lift off on a SpaceX Falcon 9 rocket from Vandenberg Space Force Base in California on March 11, 2025.Credit: SpaceX NASA’s newest astrophysics observatory, SPHEREx, is on its way to study the origins of our universe and the history of galaxies, and to search for the ingredients of life in our galaxy. Short for Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer, SPHEREx lifted off at 8:10 p.m. PDT on March 11 aboard a SpaceX Falcon 9 rocket from Space Launch Complex 4 East at Vandenberg Space Force Base in California.
Riding with SPHEREx aboard the Falcon 9 were four small satellites that make up the agency’s PUNCH (Polarimeter to Unify the Corona and Heliosphere) mission, which will study how the Sun’s outer atmosphere becomes the solar wind.
“Everything in NASA science is interconnected, and sending both SPHEREx and PUNCH up on a single rocket doubles the opportunities to do incredible science in space,” said Nicky Fox, associate administrator, Science Mission Directorate at NASA Headquarters in Washington. “Congratulations to both mission teams as they explore the cosmos from far-out galaxies to our neighborhood star. I am excited to see the data returned in the years to come.”
Ground controllers at NASA’s Jet Propulsion Laboratory in Southern California, which manages SPHEREx, established communications with the space observatory at 9:31 p.m. PDT. The observatory will begin its two-year prime mission after a roughly one-month checkout period, during which engineers and scientists will make sure the spacecraft is working properly.
“The fact our amazing SPHEREx team kept this mission on track even as the Southern California wildfires swept through our community is a testament to their remarkable commitment to deepening humanity’s understanding of our universe,” said Laurie Leshin, director, NASA JPL. “We now eagerly await the scientific breakthroughs from SPHEREx’s all-sky survey — including insights into how the universe began and where the ingredients of life reside.”
The PUNCH satellites successfully separated about 53 minutes after launch, and ground controllers have established communication with all four PUNCH spacecraft. Now, PUNCH begins a 90-day commissioning period where the four satellites will enter the correct orbital formation, and the instruments will be calibrated as a single “virtual instrument” before the scientists start to analyze images of the solar wind.
The two missions are designed to operate in a low Earth, Sun-synchronous orbit over the day-night line (also known as the terminator) so the Sun always remains in the same position relative to the spacecraft. This is essential for SPHEREx to keep its telescope shielded from the Sun’s light and heat (both would inhibit its observations) and for PUNCH to have a clear view in all directions around the Sun.
To achieve its wide-ranging science goals, SPHEREx will create a 3D map of the entire celestial sky every six months, providing a wide perspective to complement the work of space telescopes that observe smaller sections of the sky in more detail, such as NASA’s James Webb Space Telescope and Hubble Space Telescope.
The mission will use a technique called spectroscopy to measure the distance to 450 million galaxies in the nearby universe. Their large-scale distribution was subtly influenced by an event that took place almost 14 billion years ago known as inflation, which caused the universe to expand in size a trillion-trillionfold in a fraction of a second after the big bang. The mission also will measure the total collective glow of all the galaxies in the universe, providing new insights about how galaxies have formed and evolved over cosmic time.
Spectroscopy also can reveal the composition of cosmic objects, and SPHEREx will survey our home galaxy for hidden reservoirs of frozen water ice and other molecules, like carbon dioxide, that are essential to life as we know it.
“Questions like ‘How did we get here?’ and ‘Are we alone?’ have been asked by humans for all of history,” said James Fanson, SPHEREx project manager at JPL. “I think it’s incredible that we are alive at a time when we have the scientific tools to actually start to answer them.”
NASA’s PUNCH will make global, 3D observations of the inner solar system and the Sun’s outer atmosphere, the corona, to learn how its mass and energy become the solar wind, a stream of charged particles blowing outward from the Sun in all directions. The mission will explore the formation and evolution of space weather events such as coronal mass ejections, which can create storms of energetic particle radiation that can endanger spacecraft and astronauts.
“The space between planets is not an empty void. It’s full of turbulent solar wind that washes over Earth,” said Craig DeForest, the mission’s principal investigator, at the Southwest Research Institute. “The PUNCH mission is designed to answer basic questions about how stars like our Sun produce stellar winds, and how they give rise to dangerous space weather events right here on Earth.”
More About SPHEREx, PUNCH
The SPHEREx mission is managed by NASA JPL for the agency’s Astrophysics Division within the Science Mission Directorate at NASA Headquarters. BAE Systems (formerly Ball Aerospace) built the telescope and the spacecraft bus. The science analysis of the SPHEREx data will be conducted by a team of scientists located at 10 institutions in the U.S., two in South Korea, and one in Taiwan. Data will be processed and archived at IPAC at Caltech, which manages JPL for NASA. The mission’s principal investigator is based at Caltech with a joint JPL appointment. The SPHEREx dataset will be publicly available at the NASA-IPAC Infrared Science Archive.
Southwest Research Institute (SwRI) leads the PUNCH mission and built the four spacecraft and Wide Field Imager instruments at its headquarters in San Antonio, Texas. The Narrow Field Imager instrument was built by the Naval Research Laboratory in Washington. The mission is operated from SwRI’s offices in Boulder, Colorado, and is managed by the Explorers Program Office at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, for NASA’s Science Mission Directorate in Washington.
NASA’s Launch Services Program, based out of the agency’s Kennedy Space Center in Florida, provided the launch service for SPHEREx and PUNCH.
For more about NASA’s science missions, visit:
http://science.nasa.gov
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Alise Fisher
Headquarters, Washington
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Calla Cofield – SPHEREx
Jet Propulsion Laboratory, Pasadena, Calif.
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Sarah Frazier – PUNCH
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Last Updated Mar 12, 2025 EditorJessica TaveauLocationNASA Headquarters Related Terms
SPHEREx (Spectro-Photometer for the History of the Universe and Ices Explorer) Astrophysics Heliophysics Launch Services Program Polarimeter to Unify the Corona and Heliosphere (PUNCH) Science Mission Directorate View the full article
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By NASA
This video sparkles with synthetic supernovae from the OpenUniverse project, which simulates observations from NASA’s upcoming Nancy Grace Roman Space Telescope. More than a million exploding stars flare into visibility and then slowly fade away. The true brightness of each transient event has been magnified by a factor of 10,000 for visibility, and no background light has been added to the simulated images. The pattern of squares shows Roman’s full field of view.Credit: NASA’s Goddard Space Flight Center and M. Troxel The universe is ballooning outward at an ever-faster clip under the power of an unknown force dubbed dark energy. One of the major goals for NASA’s upcoming Nancy Grace Roman Space Telescope is to help astronomers gather clues to the mystery. One team is setting the stage now to help astronomers prepare for this exciting science.
“Roman will scan the cosmos a thousand times faster than NASA’s Hubble Space Telescope can while offering Hubble-like image quality,” said Rebekah Hounsell, an assistant research scientist at the University of Maryland-Baltimore county working at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and a co-principal investigator of the Supernova Cosmology Project Infrastructure Team preparing for the mission’s High-Latitude Time-Domain Survey. “We’re going to have an overwhelming amount of data, and we want to make it so scientists can use it from day one.”
Roman will repeatedly look at wide, deep regions of the sky in near-infrared light, opening up a whole new view of the universe and revealing all sorts of things going bump in the night. That includes stars being shredded as they pass too close to a black hole, intense emissions from galaxy centers, and a variety of stellar explosions called supernovae.
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This data sonification transforms a vast simulation of a cosmic survey from NASA’s upcoming Nancy Grace Roman Space Telescope into a symphony of stellar explosions. Each supernova’s brightness controls its volume, while its color sets its pitch –– redder, more distant supernovae correspond to deep, low tones while bluer, nearer ones correspond to higher frequencies. The sound in stereo mirrors their locations in the sky. The result sounds like celestial wind chimes, offering a way to “listen” to cosmic fireworks. Credit: NASA’s Goddard Space Flight Center, M. Troxel, SYSTEM Sounds (M. Russo, A. Santaguida) Cosmic Radar Guns
Scientists estimate around half a dozen stars explode somewhere in the observable universe every minute. On average, one of them will be a special variety called type Ia that can help astronomers measure the universe.
These explosions peak at a similar intrinsic brightness, allowing scientists to find their distances simply by measuring how bright they appear.
Scientists can also study the light of these supernovae to find out how quickly they are moving away from us. By comparing how fast they’re receding at different distances, scientists will trace cosmic expansion over time.
Using dozens of type Ia supernovae, scientists discovered that the universe’s expansion is accelerating. Roman will find tens of thousands, including very distant ones, offering more clues about the nature of dark energy and how it may have changed throughout the history of the universe.
“Roman’s near-infrared view will help us peer farther because more distant light is stretched, or reddened, as it travels across expanding space,” said Benjamin Rose, an assistant professor at Baylor University in Waco, Texas, and a co-principal investigator of the infrastructure team. “And opening a bigger window, so to speak, will help us get a better understanding of these objects as a whole,” which would allow scientists to learn more about dark energy. That could include discovering new physics, or figuring out the universe’s fate.
The People’s Telescope
Members of the planning team have been part of the community process to seek input from scientists worldwide on how the survey should be designed and how the analysis pipeline should work. Gathering public input in this way is unusual for a space telescope, but it’s essential for Roman because each large, deep observation will enable a wealth of science in addition to fulfilling the survey’s main goal of probing dark energy.
Rather than requiring that many individual scientists submit proposals to reserve their own slice of space telescope time, Roman’s major surveys will be coordinated openly, and all the data will become public right away.
“Instead of a single team pursuing one science goal, everyone will be able to comb through Roman’s data for a wide variety of purposes,” Rose said. “Everyone will get to play right away.”
This animation shows a possible tiling pattern of part of NASA’s Nancy Grace Roman Space Telescope’s High Latitude Time-Domain Survey. The observing program, which is being designed by a community process, is expected to have two components: wide (covering 18 square degrees, a region of sky as large as about 90 full moons) and deep (covering about 5.5 square degrees, about as large as 25 full moons). This animation shows the deeper portion, which would peer back to when the universe was about 500 million years old, less than 4 percent of its current age of 13.8 billion years.Credit: NASA’s Goddard Space Flight Center This Is a Drill
NASA plans to announce the survey design for Roman’s three core surveys, including the High-Latitude Time-Domain Survey, this spring. Then the planning team will simulate it in its entirety.
“It’s kind of like a recipe,” Hounsell said. “You put in your observing strategy — how many days, which filters — and add in ‘spices’ like uncertainties, calibration effects, and the things we don’t know so well about the instrument or supernovae themselves that would affect our results. We can inject supernovae into the synthetic images and develop the tools we’ll need to analyze and evaluate the data.”
Scientists will continue using the synthetic data even after Roman begins observing, tweaking all aspects of the simulation and correcting unknowns to see which resulting images best match real observations. Scientists can then fine-tune our understanding of the universe’s underlying physics.
“We assume that all supernovae are the same regardless of when they occurred in the history of the universe, but that might not be the case,” Hounsell said. “We’re going to look further back in time than we’ve ever done with type Ia supernovae, and we’re not completely sure if the physics we understand now will hold up.”
There are reasons to suspect they may not. The very first stars were made almost exclusively of hydrogen and helium, compared to stars today which contain several dozen elements. Those ancient stars also lived in very different environments than stars today. Galaxies were growing and merging, and stars were forming at a furious pace before things began calming down between about 8 and 10 billion years ago.
“Roman will very dramatically add to our understanding of this cosmic era,” Rose said. “We’ll learn more about cosmic evolution and dark energy, and thanks to Roman’s large deep view, we’ll get to do much more science too with the same data. Our work will help everyone hit the ground running after Roman launches.”
For more information about the Roman Space Telescope visit www.nasa.gov/roman.
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 and Caltech/IPAC in Southern 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 Rochester, New York; and Teledyne Scientific & Imaging in Thousand Oaks, California.
By Ashley Balzer
NASA’s Goddard Space Flight Center, Greenbelt, Md.
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Last Updated Mar 11, 2025 EditorAshley BalzerContactAshley Balzerashley.m.balzer@nasa.govLocationGoddard Space Flight Center Related Terms
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