NASAs Roman telescope is built to find what Hubble and Webb miss

Astronomers once stumbled on what appeared to be a black hole racing through space, a bizarre sight they only caught because the Hubble Space Telescope happened to be staring in the exact right place.

The discovery made for a juicy headline, but also served as a warning: If you’re relying on serendipity alone to find the weirdest, most revealing objects in the universe, you’re going to miss most of them.

NASA‘s Nancy Grace Roman Space Telescope, which could launch as early as Aug. 30, is the agency’s next flagship observatory and is designed to change those odds.

“It’s extraordinarily lucky that Hubble was able to catch that,” senior project scientist Julie McEnery told Mashable during a news conference in April. “Roman would be able to find some things like that in space, because we’re surveying such a large part of the sky, and then we can follow up with detailed measurements — with James Webb Space Telescope — now that we know where to look.”

Instead of looking deeply at tiny patches of sky, Roman is expected to scan huge areas quickly and find the rarest objects in the cosmos. In practice, the new telescope’s purpose is to act as a scout, mapping the universe rapidly, while Hubble, Webb, and other observatories zero in on the details.

Why Roman looks wide instead of deep

Roman’s biggest advantage over Hubble is how much more sky it can see at once. The new telescope will capture images with Hubble-like resolution in infrared light, but each picture will span at least 100 times more space.

Over its first five years, Roman is expected to image more than 50 times as much sky as Hubble has managed in three decades.

Roman will use that power to tackle some of the biggest open questions in cosmology. It will map the distribution of galaxies and galaxy clusters in space and how their structures change over time. Those patterns help test our narrative about the universe: that it began hot and dense, has been expanding and cooling ever since, and is shaped by normal matter, dark matter, and dark energy.

Dark matter is an unseen form of matter that reveals itself only through gravity. Dark energy is the name scientists give to whatever seems to be speeding up the universe’s expansion. Current measurements don’t all agree, suggesting the theory could be missing something important.

Roman is designed to sharpen that picture. It will build 3D maps of the universe, sending down about 1.4 terabytes of science data every day. A single image from the main survey would take more than 500,000 4K TVs to display — enough to cover 45 city blocks, mission leaders said.

How Roman, Webb, and Hubble work together

The legendary Hubble telescope, in orbit since 1990, sees in visible, ultraviolet, and infrared light, packing thousands of galaxies into a tiny patch of sky. With Roman in operation, Hubble will be able to focus on studies of single galaxies, star‑forming regions, or black hole candidates, all while using colors of light that Roman doesn’t cover.

Webb, launched in 2021, operates primarily in the infrared band of the spectrum. That lets it see light obscured by cosmic dust, study extremely early galaxies, and analyze the atmospheres of some exoplanets, worlds that orbit other stars.

“You could consider one of Roman’s roles to be something like a finding chart for the James Webb Space Telescope,” McEnery said.

Together, Roman and Webb behave like wide‑angle and telephoto lenses on the same camera. Roman will show the broader “ecosystem” around objects, while Webb returns to specific oddities Roman finds for more detailed looks.

“Roman isn’t just doing Hubble and Webb science faster,” said Nicky Fox, associate administrator for science at NASA. “It’s doing fundamentally different science that could not be done with either observatory. The three missions will complement each other.”

Roman will also work closely with missions beyond NASA’s own flagships.

On the ground, the Vera C. Rubin Observatory in Chile will repeatedly scan the sky in visible light, tracking how things change over time. Because its images are sometimes too blurry to separate close objects, two or more sources can blend into one.

By comparing Rubin’s images with Roman’s sharper infrared views, astronomers may be able to visually resolve those crowded scenes, improving Rubin’s maps. Both observatories will also track exploding stars, combining visible and infrared data to refine measurements of how fast the universe is expanding.

An advanced tool for exoplanets

Roman is also equipped with an advanced coronagraph, an instrument that blocks a star’s direct light so the telescope can photograph nearby planets in the star’s glare. On Roman, this coronagraph is primarily a technology demonstration, showing that it is possible to directly image large Jupiter‑like planets orbiting other stars from space.

Roman’s coronagraph technology leapfrogs existing instruments, surpassing the capabilities of Hubble, Webb, and ground‑based telescopes, said Vanessa Bailey, NASA’s coronagraph scientist for the Roman telescope.

“What astronomers can do today with coronagraph instruments is see planets that are maybe 1 million times fainter than their stars,” Bailey told Mashable. “What we’re doing with the Roman coronagraph is hopefully getting to 10 million to 100 million times fainter, maybe even a little bit more in the best‑case scenario. That might allow us to see light reflected off of the cloud tops of a cold, old Jupiter analog in visible light for the first time.”

The tech demonstration matters for what NASA hopes will come next: The proposed Habitable Worlds Observatory. This space telescope would be designed to directly photograph Earth‑like planets around sun‑like stars and search their atmospheres for “biosignatures” — gases such as oxygen and ozone that could hint at life. 

Roman, along with these other U.S. observatories, is poised to give astronomers a more complete picture of the cosmos.

“We’re going to be surveying patches of the sky, going back over and over again to find new things that go bump in the night,” McEnery said. “I very much hope, and in fact expect, that the most exciting science from Roman is going to be the things that we didn’t expect — that we couldn’t predict.”

Click here to read more >> https://mashable.com/science/nasa-nancy-grace-roman-space-telescope-vs-hubble-webb