During his senior year, Mark Evans, a 2010 grad, used the telescope at the College’s observatory to detect an extrasolar planet—a planet much like Jupiter or Saturn orbiting a star hundreds of lightyears away. Working with physics professor Dr. Jonathan Langton, Evans used the “transit” method to detect CoRoT-2b, one of some 500 (and growing) known exoplanets. CoRoT-2b is 800 lightyears from Earth and orbits its parent star every 1.7 days.

Over the course of a night, using a CCD (similar to a precision digital camera), Evans took hundreds of images of the star CoRoT-2b orbits and its neighbors. Later, he and Langton used a computer to measure the brightness of the star in each picture and graphed its brightness over the course of the night. (When a planet moves in front of a star, the star’s level of brightness drops, so even though you can’t see the planet, you can tell it’s there.)

This detection was a milestone for Principia’s observatory, proving its telescope is powerful enough not just to detect but to discover planets beyond our solar system.