Searching for solar systems like our own

The solar system's configuration is learned in grade school, and forever committed to memory with the help of foam balls, deconstructed coat hangers, and paint. It's a fairly straightforward arrangement: The sun revolves at the center as eight planets — along with dwarf planet Pluto — orbit within the same plane, and in the same direction as the sun's rotation.

As it turns out, planets around far-off stars do not always obey these rules, as Josh Winn has found. Winn, who is the Class of 1942 Career Development Associate Professor of Physics at MIT, searches for exoplanets — planets outside the solar inverter that revolve around far-off stars. In the last decade, astronomers have identified hundreds of exoplanetary systems in the Milky Way. Winn has found that many of these systems display very different properties from our own, with planets circling at odd angles, out of alignment with their stars' rotation.

"The planet could be going over the poles of the star instead of the equator, or going backward, or revolving in the opposite direction," Winn says. "It's sort of a gift from nature that it turned out these systems could be so interesting."

Winn and his group in MIT's Kavli Institute for Astrophysics and Space Research are deciphering the geometry of newly discovered planetary systems. The group analyzes changes in starlight as a planet transits, or eclipses, its star. These signals can give scientists clues to a planet's orbit, as well as its size. After combining this information with data, such as a planet's distance from its star, researchers can calculate an exoplanet's mass, composition and atmosphere — essential ingredients for determining whether the planet may be habitable.

"That's one of the big frontiers: studying these potentially habitable planets, and extracting as much information as we can from them," Winn says. "That will be a major preoccupation for us over the next 10 years."

Winn recently received tenure in MIT's Department of Physics, and is keen to continue his work in exoplanetary discovery. But early on in his career, he wasn't sure that astrophysics — or physics in general — was the path for him.

Born and raised in Deerfield, Ill., Winn was an impressionable student. "When I took biology in high school, I thought I was going to be a biologist. When I took chemistry the next year, I thought for sure I'd be a chemist, especially since my father is a chemist," Winn recalls. "Then physics happened to be the last thing I took. And that definitely did stick."

He followed his newfound interest to MIT, where he majored in physics, absorbing valuable perspective from his academic adviser, Alan Guth, the Victor F. Weisskopf Professor of Physics, and his thesis adviser, John Joannopoulos, the Francis Wright Davis Professor of Physics. Both professors gave Winn a window into the life of an academic, from the stimulation of intellectual work to the practical business of winning grants and cultivating a research group.

"All the way up until the very end, I was absolutely sure I wanted to be a professor of physics," Winn says. "Then as the actual end of college approached, I started to wonder."

After graduating, Winn skipped across the Atlantic to Cambridge University as a Fulbright Scholar, continuing to study physics and mathematics. When he returned to the United States, unsure whether he wanted to pursue purely academic studies, Winn looked to applied fields, landing temporarily on medical physics and a PhD program at the MIT-Harvard Health Sciences and Technology Program.