The two missions will study this as-yet-unexplained phenomenon in complementary ways.
A new space telescope named Euclid, an ESA (European Space Agency) mission with important contributions from NASA, is set to launch in July to explore why the universe’s expansion is speeding up. Scientists call the unknown cause of this cosmic acceleration “dark energy.” By May 2027, NASA’s Nancy Grace Roman Space Telescope will join Euclid to explore this puzzle in ways that have never been possible before.
Credit: NASA’s Goddard Space Flight Center.
“Twenty-five years after its discovery, the universe’s accelerated expansion remains one of the most pressing mysteries in astrophysics,” said Jason Rhodes, a senior research scientist at NASA’s Jet Propulsion Laboratory in Southern California. Rhodes is a deputy project scientist for Roman and the U.S. science lead for Euclid. “With these upcoming telescopes, we will measure dark energy in different ways and with far more precision than previously achievable, opening up a new era of exploration into this mystery.”
Scientists are unsure whether the universe’s accelerated expansion is caused by an additional energy component or whether it signals that our understanding of gravity needs to be changed in some way. Astronomers will use Roman and Euclid to test both theories at the same time, and scientists expect both missions to uncover important information about the underlying workings of the universe.
Euclid and Roman are both designed to study cosmic acceleration, but using different and complementary strategies. Both missions will make 3D maps of the universe to answer fundamental questions about the history and structure of the universe. Together, they will be much more powerful than either individually.
Euclid will observe a far larger area of the sky – approximately 15,000 square degrees, or about a third of the sky – in both infrared and optical wavelengths of light, but with less detail than Roman. It will peer back 10 billion years to when the universe was about 3 billion years old.
Roman’s largest core survey will be capable of probing the universe to a much greater depth and precision, but over a smaller area – about 2,000 square degrees, or one-twentieth of the sky. Its infrared vision will unveil the cosmos when it was 2 billion years old, revealing a larger number of fainter galaxies. While Euclid will focus on cosmology exclusively, Roman will also survey nearby galaxies, find and investigate planets throughout our galaxy, study objects in the outskirts of our solar system, and much more.
The Dark Energy Hunt
The universe has been expanding ever since its birth – a fact discovered by Belgian astronomer Georges Lemaître in 1927 and Edwin Hubble in 1929. But scientists expected the gravity of the universe’s matter to gradually slow that expansion. In the 1990s, by looking at a particular kind of supernova, scientists discovered that about 6 billion years ago, dark energy began ramping up its influence on the universe, and no one knows how or why. The fact that it’s speeding up means that our picture of the cosmos is missing something fundamental.
Euclid’s Near Infrared Spectrometer and Photometer (NISP) instrument sensor-chip electronics, JPL led the procurement and delivery of the NISP detectors. Those detectors were tested at NASA’s Goddard Space Flight Center. The Euclid NASA Science Center at IPAC (ENSCI), at Caltech, will support U.S.-based investigations using Euclid data.
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 Ball Aerospace and Technologies Corporation in Boulder, Colorado; L3Harris Technologies in Melbourne, Florida; and Teledyne Scientific & Imaging in Thousand Oaks, California. Caltech manages JPL for NASA.
For more information about Roman go to:
https://roman.gsfc.nasa.gov/
Credit: NASA/JPL Caltech.
