Penn cosmologists join new space telescope mission



The Euclid spacecraft, shown in this artist’s impression, is scheduled to launch in 2020. The space telescope is designed to probe the mysteries of dark energy and dark matter.

Penn has long played a leadership role in the search for two of the most elusive phenomena in astronomy: dark matter and dark energy. The two related concepts try to explain the apparently “missing” mass of the universe, and why the universe’s expansion is accelerating, rather than slowing down due to gravity. 

Professors Bhuvnesh Jain and Gary Bernstein, both of the Department of Physics and Astronomy in the School of Arts & Sciences, have major roles in the Dark Energy Survey, an international collaboration to study the mysterious force using a new imaging system recently installed at an observatory in the Chilean Andes.  

Now, the two are preparing to take their studies from the mountaintop to a point almost a million miles further, via a space telescope named Euclid slated to launch at the end of the decade.    

“The pristine conditions in space will allow us to take pictures with exquisite clarity, which is evident if you’ve seen images from Hubble Space Telescope,” says Jain. “But Euclid can take pictures faster than Hubble and get infrared images which are simply impossible to obtain from the ground. That will make it an incredibly useful partner to missions based on the ground, like the Dark Energy Survey.”

In January, NASA joined its transatlantic counterpart, the European Space Agency, on its Euclid mission, which will study both dark matter and dark energy by taking pictures of about two billion galaxies.  

NASA’s contribution includes hardware—a set of 20 infrared detectors that will be used in one of the satellite's imaging instruments—as well as expertise. Three teams of U.S. researchers, totaling 43 scientists, will assist in the mission’s planning and data analysis. As members of this group, Jain and Bernstein will work with the team from NASA’s Jet Propulsion Laboratory.  

One of the methods the Euclid team will use is known as “weak gravitational lensing,” a technique that Jain and Bernstein are also employing through the Dark Energy Survey.

“We can’t see dark matter or dark energy directly, so we look at the way they bend the light that is on the way to us from galaxies. Looking through the air, you can’t tell whether small galaxies have been distorted or not, because they just look like blurry dots,” Bernstein says. “If we can put a satellite in space and take pictures with it, we’ll be able to add new information from over a billion small, distant galaxies to our analysis.”

Originally published on February 14, 2013