The grand jigsaw of planet formation

A few decades ago, discovering planets orbiting stars other than the Sun (which we call exoplanets) was more science fiction than science. Today, students here at UW–Madison are currently sorting through data and discovering new planets to add to the collection of roughly 6,000 exoplanets which have been found so far. This is possible thanks to space telescopes, such as NASA’s Transiting Exoplanet Survey Satellite which constantly scans the skies for dips in starlight that might signal a planet passing in front of a distant star, and the Wisconsin-Indiana-Yale-National Optical Astronomy Observatories (WIYN) telescope in Arizona, which allows us to confirm that the planets are real once they are found.

But discovering planets is only the first step. My major research interest is understanding how planets form. When we look at some of the surprising new types of exoplanets out there, we realize our existing theories can’t fully explain them. Some are larger than Jupiter yet orbit closer to their stars than Mercury does, and others are sizes that we don’t even see in our own Solar System. This is where my research group steps in. My own research focuses on developing a theory that explains the formation of every type of world we see. Since our current theories fall short for many newly discovered worlds, I try to bridge the gap with new ideas, using both computer models and classic paper-and-pencil mathematics.

Our computer simulations are made possible by the Wisconsin Center for High Throughput Computing. These computers allow us to simulate the processes of planet formation: how smaller pieces of rock build up into planets and then how planets interact with each other after they form. The undergraduate students who work in my lab learn not only how to run these simulations, but also how to analyze vast amounts of computer data and help make sense of planetary birth and evolution.

The big question that follows is habitability. Even if we successfully confirm a planet’s existence and figure out how it formed, we still want to know if it could support life. “Habitability” doesn’t necessarily mean life actually exists there (no one has discovered alien life yet!), but it does mean a planet could have the right conditions, such as liquid water or a protective atmosphere, to support developing life. Investigating these conditions takes the combined efforts of geologists (who study planetary surfaces), climate scientists (who model atmospheres), chemists (who explore the chemical building blocks of life) and astronomers like me (who find the planets and figure out how they formed). That’s exactly why the Wisconsin Center for Origins Research was founded: to bring all these disciplines under one roof so we can share data, theories, ideas and perspectives.

At the University of Wisconsin–Madison, we’re in a remarkable era for astronomy and planetary science. With so many new exoplanet discoveries, powerful simulation tools and interdisciplinary research teams, we’re closer than ever to answering some of humanity’s oldest questions: Where do planets come from? How do they evolve? And might we one day find another world like our own?

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About the Author

Juliette Becker is an assistant professor of astronomy at the University of Wisconsin–Madison and a founding member of the Wisconsin Center for Origins Research. She studies exoplanet dynamics and planet formation, and she is passionate about teaching UW–Madison undergraduates how to conduct scientific research.

This content was produced by UW-Madison’s College of Letters & Science. The news and editorial departments of the Wisconsin State Journal had no role in its creation or display. For more information, contact events@madison.com