Simulating the Universe

Deep dives into synthetic data reveal new possibilities in astronomy.

Molly Peeples
Dr. Molly Peeples

Dr. Molly Peeples was hooked by astronomy as a physics undergrad at MIT when she heard about the Wilkinson Microwave Anisotropy Probe (WMAP)—a mission that created an all-sky map of the universe 375,000 years after the big bang, ultimately helping to prove this was a period of rapid expansion. That’s why she started pursuing research, first as an undergrad and now as an astronomer at the institute. Here, Dr. Peeples shares why she finds her work as an associate astronomer at the institute so rewarding.

Why did you choose to pursue astronomy?

I always knew I wanted to go into scientific research to answer questions we didn’t know the answers to. I was searching for a research project in physics to do as an undergraduate when the WMAP cosmology result came out, which eventually led to me pursuing my doctorate in astronomy.

Why is ongoing research so important to you?

Research is important to me for the reasons that drew me to science in the first place: I continually get to discover new things about the universe, and how it works. It’s thrilling to pose questions about why galaxies are the way they are, and to be able to address those questions using a combination of simulations run on supercomputers and observations taken with amazing observatories such as Hubble. Plus, I have a network of collaborators across the country, including staff at the institute and postdocs at Johns Hopkins University, with whom I thoroughly enjoy working. We’re all learning from each other all the time and sharing in the process of discovery.

Which projects are you currently part of at the institute?

Right now, my work is split between leading the FOGGIE (Figuring Out Gas & Galaxies In Enzo) research team and contributing to projects that support the institute’s missions. In the past few years, I’ve helped create an online archive of science ready data from Hubble’s Cosmic Origins Spectrograph to streamline researchers’ work when they pull data. I also support the Nancy Grace Roman Space Telescope mission by helping teams generate synthetic data that act like real data to maximize the science return from the observatory. One reason the mission work is appealing is that I enjoy working on different projects and enabling other scientists to do their research.

With FOGGIE, we’re trying to answer how galaxies evolve in conjunction with the diffuse gas around them. To make new stars, galaxies require new supplies of gas. When stars die as supernova explosions, they expel freshly produced heavy elements back into galaxies’ diffuse environs. How do these physical processes drive galaxy evolution? We’re creating very high-resolution galaxy simulations that trace this diffuse gas, and then using synthetic data to compare our simulated universe to data from observatories like Hubble and the Keck telescopes. Right now, our team is relatively small, but these simulations have so much scientific potential that my goal is to expand the FOGGIE team to a larger group of collaborators so we can more fully explore how galaxies and their gas co-evolve. Generating synthetic data to analyze and think about in the same way as real data is a critical piece of the FOGGIE project, so being surrounded by people carefully thinking about observations and instrumentation at STScI has been beneficial to my research.

What do you enjoy most about your work at STScI?

I like how big STScI is: There are so many people here working on so many things that there’s almost guaranteed to be an expert nearby on any topic. But more generally, it’s invigorating to be surrounded by a diverse set of people all working to push the frontiers of astronomy, and helping enable others to do the same.

Learn more about Dr. Peeples's research interests.

Article updated March 2019.