With decades of Pitt researchers’ input, the Nancy Grace Roman Space Telescope preps for launch

The Nancy Grace Roman Space Telescope is scheduled to launch from NASA's Kennedy Space Center shortly before 7:30 a.m. Aug. 30. Researchers from the University of Pittsburgh have spent decades working on Roman (pictured above) along with other recent missions, including the Vera C. Rubin Legacy Survey of Space and Time and the Dark Energy Spectroscopic Instrument.

Two of those professors are Michael Wood-Vasey and Jeffrey Newman, both in the Department of Physics and Astronomy in the Kenneth P. Dietrich School of Arts and Sciences. Wood-Vasey is working with Mi Dai, a research assistant professor, to investigate the nature of dark energy using light emitted from a specific type of star known as a type Ia supernova.

Dark energy is a mysterious component of the universe that is causing the expansion of the universe to speed up despite the attractive force of gravity. The extra "push" provided by dark energy is greater than gravity's ability to pull objects together.

Newman and Brett Andrews, a research associate professor, are working to turn the detailed images from Roman into accurate 3D maps of the universe. Newman is leading efforts to obtain new data from the Subaru Telescope in Hawaii that will be used to refine methods for making these maps, including extending them to include the most distant galaxies.

Once online, Roman will capture thousands of supernovae, as well as track the gravitational effects of dark matter - an as-of-yet unidentified class of matter that makes up most of the matter in the universe - among other projects, such as creating a survey of planets outside our solar system, known as exoplanets.

Combining Roman's data with information from other missions should help researchers home in on a puzzle the field is trying to solve: Why do different methodologies seem to suggest dark energy behaves differently at different times in the universe's history? Is dark energy simply the ambient energy of space, or is there something else going on?

"We want to be able to say we've got three or four different handles on dark energy," Newman said, "And then ask, 'are they telling us the same thing?'" If insights gleaned from supernovae, studying far-off galaxies and mapping dark matter continue to be validated, "That gives you a lot more confidence that we really are seeing the properties of dark energy change over time rather than our measurement methods being imperfect."

This work is being carried out by several missions. So far, findings from DESI - which officially ended its five-year mission in April 2026 - and Rubin suggest dark energy was behaving differently at different times across the 13.8-billion-year history of the universe. So far, there is an unimaginable amount of data, but no proposed theory has yet emerged as the clear winner.

"This is a field where the observations are clearly far out in front of theory and thus call for investigation by multiple pathways to confirm the observational results," Wood-Vasey said.

He plans to analyze type Ia supernovae from two distinct periods: the early universe, when gravity was the dominant force, slowing down the expansion of the universe, and the later universe, when dark energy, which grows in magnitude as the universe grows in size, appears to have overtaken gravity as the dominant force, accelerating the universe's expansion

"We're really trying to go to that next step of making our measurements more precise," Newman said. "We want to see where our models break down and get hints about what dark energy might be."

Photography by Sydney Rohde/NASA