Astrophysics professor Karl Gebhardt is finding new ways to study the mysteries of the universe. 

Gebhardt has been using gravitational waves, or ripples of space-time, as a way to study the properties of black holes, neutron stars and supernovas. 

“I consider the detection of gravitational waves among the top handful of most important scientific advances in the history of humans,” Gebhardt said. “Since Einstein, we knew that space and time were physical entities, and now we are just starting to interact directly with them. It gives me goosebumps when I think about it.”

Gebhardt’s work focuses on explaining black holes for the purpose of explaining gravity and the expansion of the universe. 

“We still do not understand what goes on inside a black hole, and to do so would require us to merge both quantum physics (study of small particles) with gravity,” Gebhardt said. 

He said gravitational waves merge these two areas, allowing physicists to study supernovae and black holes on large scales, which also helps explain how gravity works in space. 

“(Understanding gravity) will have important implications for where the universe came from and where it is going,” Gebhardt said. 

In February, Gebhardt began using gravitational waves to test for dark energy, a term used to describe the expansion of the universe. 

“Dark energy is the phrase we apply to represent our ignorance of how the universe is expanding,” Gebhardt said. “It is just a phrase! It may not be dark, it may not be energy. Our universe is expanding about three times faster that what we expected.” 

Gebhardt said the first measure of gravity waves will come from the strongest signals. He added that these strongest signals are merging black holes, which can be observed using gravitational waves.

In addition to his research, Gebhardt is also one of the main architects of the $34-million Hobby-Eberly Telescope Dark Energy Experiment, or HETDEX,which serves to measure light from galaxies nearly 10 billion light years away. 

“(HETDEX) will take this light and split it up into a spectrum, much like a prism,” Gebhardt said. “From that information, we can determine how far away the galaxy is.” 

Gebhardt said HETDEX will essentially be able to provide a map of the galaxy, while encoding information for the universe expanding and the physics behind dark energy. 

The discovery of gravitational waves provides astronomers a new tool to test for dark energy, while it gives us as humans a better appreciation of our place in the universe. 

“I hope this would give us a better appreciation for our home and for each other,” Gebhardt said. “We certainly need a lot more of that in the current climate!”