Core Survey by NASA’s Roman Mission Will Unveil Universe’s Dark Side - UNIVERSE

The broadest planned survey by NASA’s upcoming Nancy Grace Roman Space Telescope will reveal hundreds of millions of galaxies scattered across the cosmos. After Roman launches as soon as this fall, scientists will use these sparkly beacons to study the universe’s shadowy underpinnings: dark matter and dark energy.

“We set out to build the ultimate wide-area infrared survey, and I think we accomplished that,” said Ryan Hickox, a professor at Dartmouth College in Hanover, New Hampshire, and co-chair of the committee that shaped the survey’s design. “We’ll use Roman’s enormous, deep 3D images to explore the fundamental nature of the universe, including its dark side.”

This infographic describes the High-Latitude Wide-Area Survey that will be conducted by NASA’s Nancy Grace Roman Space Telescope. This observation program will cover more than 5,000 square degrees (about 12 percent of the sky) in just under a year and a half. Scientists will use the survey to analyze hundreds of millions of galaxies scattered across the cosmos that reveal clues about the universe’s shadowy underpinnings — dark matter and dark energy — as well as a wealth of other science topics.

NASA’s Goddard Space Flight Center

Roman’s High-Latitude Wide-Area Survey is one of the mission’s three core observation programs. It will cover more than 5,000 square degrees (about 12 percent of the sky) in just under a year and a half. Roman will look far from the dusty plane of our Milky Way galaxy (that’s what the “high-latitude” part of the survey name means), looking up and out of the galaxy rather than through it to get the clearest view of the distant cosmos.

“This survey is going to be a spectacular map of the cosmos, the first time we have Hubble-quality imaging over a large area of the sky,” said David Weinberg, an astronomy professor at Ohio State University in Columbus, who played a major role in devising the survey. “Even a single pointing with Roman needs a whole wall of 4K televisions to display at full resolution. Displaying the whole high-latitude survey at once would take half a million 4K TVs, enough to cover 200 football fields or the cliff face of El Capitan.”

The survey will combine the powers of imaging and spectroscopy to unveil a goldmine of galaxies strewn across cosmic time. Astronomers will use the survey’s data to explore invisible dark matter, detectable only via its gravitational effects on other objects, and the nature of dark energy — a pressure that seems to be speeding up the universe’s expansion.

“Cosmic acceleration is the biggest mystery in cosmology and maybe in all of physics,” Weinberg said. “Somehow, when we get to scales of billions of light years, gravity pushes rather than pulls. The Roman wide area survey will provide critical new clues to help us solve this mystery, because it allows us to measure the history of cosmic structure and the early expansion rate much more accurately than we can today.”

Weighing shadows

Anything that has mass warps space-time, the underlying fabric of the universe. Extremely massive things like clusters of galaxies warp space-time so much that they distort the appearance of background objects — a phenomenon called gravitational lensing.

“It’s like looking through a cosmic funhouse mirror,” Hickox said. “It can smear or duplicate distant galaxies, or if the alignment is just right, it can magnify them like a natural telescope.”

This simulation shows the type of science astronomers will be able to do with future observations from NASA’s Nancy Grace Roman Space Telescope. The sequence demonstrates how the gravity of intervening galaxy clusters and dark matter can distort the light from farther objects, warping their appearance. More intervening material creates stronger distortions. By analyzing these features, astronomers can study elusive dark matter, which can only be measured indirectly through its gravitational effects on visible matter. As a bonus, the distortion acts like a telescope, enabling observations of extremely distant galaxies. Simulations like this one help astronomers understand what Roman’s future observations could tell us about the universe, and provide useful data to validate data analysis techniques.

Caltech/IPAC/R. Hurt

Roman’s view will be large and sharp enough to study this lensing effect on a small scale to see how clumps of dark matter warp the appearance of distant galaxies. Astronomers will create a detailed map of the large-scale distribution of matter — both seen and unseen — throughout the universe and fill in more of the gaps in our understanding of dark matter. Studying how structures grow over time will also help astronomers explore dark energy’s strength at various cosmic stages.

“The data analysis standards required to measure weak gravitational lensing are such that the astronomy community as a whole will benefit from very high-quality data over the full survey area, which will undoubtedly lead to unexpected discoveries,” said Olivier Doré, a senior research scientist at NASA’s Jet Propulsion Laboratory in Southern California, who leads a team focused on Roman imaging cosmology with the High-Latitude Wide-Area Survey. “This survey will accomplish much more than just revealing dark energy!”

While NASA’s Hubble and James Webb space telescopes both also study gravitational lensing, the breakthrough with Roman is its large field of view.

“Weak lensing distorts galaxy shapes too subtly to see in any single galaxy — it’s invisible until you do a statistical analysis,” Hickox said. “Roman will see more than a billion galaxies in this survey, and we estimate about 600 million of them will be detailed enough for Roman to study these effects. So Roman will trace the growth of structure in the universe in 3D from shortly after the big bang to today, mapping dark matter more precisely than we’ve ever done before.”

Sounding out dark energy

Roman’s wide-area survey will also gather spectra from around 20 million galaxies. Analyzing spectra helps show how the universe expanded during different cosmic eras because when an object recedes, all of the light waves we receive from it are stretched out and shifted toward redder wavelengths — a phenomenon called redshift.

By determining how quickly galaxies are receding from us, carried by the relentless expansion of space, astronomers can find out how far away they are — the more a galaxy’s spectrum is redshifted, the farther away it is. Astronomers will use this phenomenon to make a 3D map of all the galaxies measured within the survey area out to about 11.5 billion light-years away.

That will reveal frozen echoes of ancient sound waves that once rippled through the primordial cosmic sea. For most of the universe’s first half-million years, the cosmos was a dense, almost uniform sea of plasma (charged particles).

Rare, tiny clumps attracted more matter toward themselves gravitationally. But it was too hot for the material to stick together, so it rebounded. This push and pull created waves of pressure—sound — that propagated through the plasma.

This animation illustrates how small particles (in this case, sand) behave when exposed to different sound frequencies. In the very early universe, a cosmic “hum” created ripples in the primordial soup that filled space. Since the ripples were places where more matter was collected, like the rings of sand shown here, slightly more galaxies formed along them than elsewhere. As the universe expanded over billions of years, so did these structures. By comparing their size during different cosmic epochs, astronomers can trace the universe’s expansion.

Nigel Stanford (used with permission)

Over time, the universe cooled and the waves ceased, essentially freezing the ripples (called baryon acoustic oscillations) in place. Since the ripples were places where more matter was collected, slightly more galaxies formed along them than elsewhere. As the universe expanded over billions of years, so did these structures.

These rings act like a ruler for the universe. Today, they are about 500 million light-years wide. Roman will precisely measure their size across cosmic time, revealing how dark energy may have evolved.

Recent results from other telescopes hint that dark energy may be shifting in strength over cosmic time. “Roman will be able to make high precision tests that should tell us whether these hints are real deviations from our current standard model or not,” said Risa Wechsler, director of Stanford University’s KIPAC (Kavli Institute for Particle Astrophysics and Cosmology) in California and co-chair of the committee that shaped the survey’s design. “Roman’s imaging survey combined with its redshift survey give us new information about the evolution of the universe — both how it expands and how structures grow with time — that will help us understand what dark energy and gravity are doing at unprecedented precision.”

Altogether, Roman will help us understand the effects of dark energy 10 times more precisely than current measurements, helping discern between the leading theories that attempt to explain why the expansion of the universe is speeding up.

Because of the way Roman will survey the universe, it will reveal everything from small, rocky objects in our outer solar system and individual stars in nearby galaxies to galaxy mergers and black holes at the cosmic frontier over 13 billion years ago.

“Roman is exciting because it covers such a wide area with the image quality only available in space,” Wechsler said. “This enables a broad range of science, from things we can anticipate studying to discoveries that we haven’t thought of yet.” 

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 Rochester, New York; and Teledyne Scientific & Imaging in Thousand Oaks, California.

By Ashley Balzer
NASA’s Goddard Space Flight Center, Greenbelt, Md. 

Source: Core Survey by NASA’s Roman Mission Will Unveil Universe’s Dark Side - NASA

Stabilized iron catalyst could replace platinum in hydrogen fuel cells - Engineering - Energy & Green Tech

iCVD catalyst: synthesis and principles. Credit: Nature Catalysis (2026). https://doi.org/10.1038/s41929-026-01482-2 

Japan and California have embraced hydrogen fuel-cell technologies, a form of renewable energy that can be used in vehicles and for supplying clean energy to manufacturing sectors. But the technology remains expensive due to its reliance on precious metals such as platinum. Engineers at Washington University in St. Louis are working on this challenge, finding ways to stabilize ubiquitous iron components for use in fuel cells to replace the expensive platinum metals, which would make hydrogen fuel-cell vehicles more affordable.

Cost challenges for fuel-cell vehicles

"The hydrogen fuel cell has been successfully commercialized in Japan and California in the U.S.," said Gang Wu, a professor of energy, environmental and chemical engineering at the McKelvey School of Engineering. "But these vehicles struggle to compete with the battery vehicle and combustion engine vehicle, with cost being the main issue."

A typical $30,000 gas-powered vehicle could cost $70,000 as a fuel-cell vehicle, he estimated. The platinum catalysts are the most expensive component, accounting for about 45% of the total cost of fuel cell stacks. Notably, the precious metal in fuel cells cannot benefit from economies of scale, and a significant rise in demand for fuel-cell power systems further drives up the already high price of platinum.

Stabilizing iron catalysts

In research published in Nature Catalysis, Wu and his team outlined how they stabilize iron catalysts for use in the fuel cell, which would lower costs for fuel-cell vehicles and other niche applications such as low-altitude aviation and artificial intelligence data centers.

Hydrogen fuel cells work to generate electricity with zero emissions via hydrogen and oxygen, two constituent parts of water. By way of a catalyst, the two elements produce water, electricity and heat until the on-board hydrogen is depleted, while oxygen is drawn from unlimited air. People can refuel their hydrogen fuel-cell vehicles at large stations, similar to how fleets of school buses refuel at the same central station, so the refueling infrastructure challenge can be readily overcome. It's clean energy, but the precious metals used in the vehicle can add significantly to the total cost, preventing its widespread adoption.

Efficiency and infrastructure considerations

According to the Environmental and Energy Study Institute, fuel cells can extract more than 60% of their fuel's energy while internal combustion engines recover less than 20% of gasoline's energy. That efficiency can reach 85% when the heat a fuel cell generates is also harnessed for electricity.

Unlike electric battery-run cars, people can't recharge fuel-cell vehicles using their home electricity sources. So there needs to be affordable and easily accessible hydrogen refueling infrastructure for this clean tech to take off. Making use of plentiful and affordable iron catalysts would go a long way to lowering those costs. But first, researchers needed to make iron more stable to handle the fuel-cell chemistry involved.

How the new catalyst method works

Wu and his team did so by creating a chemical vapor of gases that can stabilize the iron catalysts during thermal activation, an innovative approach to significantly improve catalyst stability while maintaining adequate activity in proton exchange membrane fuel cells (PEMFCs). The result vastly improved iron catalysts' durability along with increased energy density and life span.

The team chose PEMFCs among different fuel types because they best serve heavy-duty vehicles, things like transport trucks, buses and construction equipment—vehicles that already go to centralized fueling centers. It's most affordable and efficient for the technology to be first adopted by heavy-duty vehicle fleets, which would further lower costs as it becomes widespread and further efficiencies of scale come on board.

"After suffering from poor stability for decades, now we are able to address the critical problem," said Wu, who explained that next steps will include further refining their processes to make iron catalysts even better than precious metals for the fuel cells of tomorrow. 

Provided by Washington University in St. Louis   

by Leah Shaffer, Washington University in St. Louis

edited by Gaby Clark, reviewed by Robert Egan 

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