Montana State University doctoral student Ethan McKeever is pictured Wednesday, Aug. 27, 2025, in Bozeman, Montana. McKeever, an astrophysicist, recently won a prestigious and highly competitive NASA FINESST grant. MSU photo by Colter Peterson

BOZEMAN – They zip frequently through solid objects, including us, but we never even notice them – ripples in space-time known as gravitational waves, which were spawned billions of light-years ago by such cosmic events as the mergers of black holes or neutron stars.

First theorized to exist by Einstein in 1916, gravitational waves evaded direct detection until Sept. 14, 2015, when one was picked up by sensitive, ground-based instruments in Washington and Louisiana. The characteristics of that wave and the hundreds of others detected since tell scientists much about the events that created them. For example, based on the frequency, strength and intensity of that very first wave, scientists know it was generated by the merger of two massive black holes located 1.3 billion light-years away.

Far less is known about lower-frequency gravitational waves that are too weak to be distinguished from Earth’s seismic motion. That’s expected to change in the next decade, after a new space-based system called LISA is deployed to detect gravitational waves with wavelengths between 1.8 million and 18 billion miles. Thanks to NASA-funded research currently being conducted by a Montana State University graduate student, scientists will be better prepared than they are now to interpret the data that LISA returns.

Ethan McKeever, a second-year doctoral student in the Department of Physics in the College of Letters and Science, is one of 24 students recently awarded a $150,000 research grant through Future Investigators in NASA Earth and Space Science, or FINESST, one of the space agency’s most prestigious funding programs. FINESST grants, which are distributed over three years and applied to tuition, other educational expenses and a stipend, are awarded for well-defined research on topics of significance to NASA. McKeever’s proposal was one of only 24 selected from 456 applications submitted for 2025 in the astrophysics division.

Hang Yu, MSU assistant professor of physics and McKeever’s faculty adviser, was not surprised that his student’s proposal was among the 5% selected.

“Ethan is an exceptionally well-prepared student to conduct research in astrophysics,” Yu said. “In his first year, he already started a research project investigating the detectability of nova-like explosions by the upcoming LISA mission, a topic we proposed to FINESST. I am confident that Ethan will have a productive and successful career at MSU with the support of the FINESST award.” 

Building on his first-year work, McKeever will continue to study the effects of nova explosions on gravitational waves. Nova explosions occur when two stars – at least one of them a white dwarf star – are gravitationally bound to each other in a system called a binary, and the white dwarf star pulls in material from the companion star, resulting in significant transfer of mass that can eventually trigger a thermonuclear explosion.

“I’m excited to figure out what the wave signatures from that are going to look like,” McKeever said.

For the FINESST study, McKeever and Yu will create simulated data using example values for given gravitational wave frequencies. They then will add “noise” – unwanted data that originate from sources other than the phenomenon being studied – and work to match the resulting data to known waveforms.

When simulating the signal, they will consider various effects that can occur in realistic compact white dwarf binaries, ranging from nova-like explosions to a binary’s interaction with other celestial bodies nearby. Many of the effects have not been widely studied but may lead to crucial signatures in the gravitational waves that one day will be detected by LISA.

McKeever said that identifying the waveforms for such events now will be very valuable when LISA begins to return data in the mid-2030s. Scientists believe LISA will individually detect in gravitational waves tens of thousands of compact white dwarf binaries throughout the Milky Way – far more than the handful of systems currently observed using traditional optical telescopes in our solar neighborhood.

McKeever, who is originally from Massachusetts and earned his bachelor’s degree in astrophysics at the University of Virginia, chose to pursue his doctorate at MSU because of the university’s reputation for gravitational research.

“There’s a nice mix of research at MSU,” he said. “I’m excited to dive more into mass transferring binaries and more theoretical modeling.”