(Photo by P. Marenfeld - NOAO/AURA/NSF) Mayall Telescope at Kitt Peak where the 3-D mapping instrument will be installed.

An instrument being built for Kitt Peak National Observatory near Tucson will allow a look back in time — and that will enhance concepts developed by Albert Einstein about how dark energy is driving expansion of the universe.

A University of Arizona (UA) astronomy professor Dr. Xiaohui Fan is among the scientists working on the 3-D galaxy mapping project to be installed on a telescope at Kitt Peak.

“I really hope we could in the end get some more information about what the nature of dark energy is. Right now the best guess is what we call the cosmological constant, that is a concept invented by Einstein 80 years ago," said Fan.

Fan said UA is helping create a navigation map to guide scientists when the spectroscope starts working in 2019.

“Any new information about how the expansion of the universe changes over time is going to tell us a lot about what dark energy might be," the astronomer said. "It may be our only hope to figure out what is actually turned out to be the dominating force in the universe is.”

He said the spectroscope will measure the light from more than 35 million celestial objects in five years. That light will reveal how fast the objects are moving away.