What we can’t see might tell us a lot about what we can see, assistant professor of physics says


Space is full of large planets and bright stars. Between all of that is energy we cannot see — it’s called “dark matter” and it could change a lot of what we know about the universe.

Kansas State assistant professor of physics Lado Samushia will conduct research for the U.S. Department of Energy on the Dark Energy Spectroscopic Instrument project. The focus of DESI is to learn more about how dark energy affects the expansion of the universe.

“One thing that we know about the universe is that it used to be really, really uniform,” Samushia said. “So things looked almost exactly the same everywhere.”

As the universe expands, gravity plays a role in how galaxies are formed and positioned.

“Gravity makes things stick together and form to each other,” Samushia said.

The force of gravity brought galaxies closer together and formed clumps of galaxies which has made our universe more uniform, Samushia said.

Between those clumps is dark energy, a type of energy that pushes things away — essentially, it reacts in the opposite way that gravity does, Samushia said, and it makes up 70 percent of the universe.

Samushia said DESI will allow astronomers to look further into our universe than ever before. The telescope can see 5,000 galaxies per exposure to the sky. Altogether, DESI will observe 35 million galaxies, looking about 11 billion lightyears.

Samushia said he will spend four days in January at Kitt Peak National Observatory in Tuscon, Arizona, where the telescope is located.

“I’m more of a theorist. So, when I go there I’m just an extra pair of hands,” Samushia said.

Samushia said his main job for the DESI project will be analyzing the data that comes back.

“So you have light from those 35 million galaxies, you have to somehow use math and statistics — somehow convert that information into something,” he said.

Samushia said the first usable data will come out in 2021, a year after service. They will then be able to make conclusion statements.

“In two years from now there will be the first set of scientific papers and statements about dark energy and the universe,” Samushia said. “And then in five years we will have all the data, and we’ll see what we see.”