Jason Rhodes, a senior research scientist at NASA’s Jet Propulsion Laboratory and a deputy project scientist for Roman, is also the U.S. science lead for Euclid. As he explained in a recent NASA“Twenty-five years after its discovery, the Universe’s accelerated expansion remains one of the most pressing mysteries in astrophysics.
In this case, the observatories will look for subtle effects caused by less concentrated masses, like clumps of. This data will be used to make a 3D map of Dark Matter, which is theorized to account for approximately 85% of matter in the known Universe and is what holds galaxies and galaxy clusters together.
Roman will also conduct an additional survey of Type Ia supernovae and study how quickly they appear to be moving away from us. Comparing the speed at which they are receding at different distances, scientists will have another means of tracing cosmic expansion and shed light on if and how the influence of Dark Energy has changed over time. They will employ different but complementary strategies to accomplish this and will be much more powerful together than either will be on its own.
Euclid will rely on optical and infrared instruments to observe an area measuring approximately 15,000 square degrees – much larger than the area observed by Roman. It will peer back 10 billion years, roughly 3 billion years after the Big Bang, when the Universe was expanding much slower than it is today. Meanwhile, Roman will study an area measuring about 2,000 square degrees but in much greater depth and detail.