100 Years Ago an Exoplanet was Unknowingly Discovered

Long before the first confirmed planetary finds in the 1990s, an observer in 1917 caught evidence of planetary debris around a new star, new research into an astronomical glass plate reveals.

April 12, 2016
4:47 PM EDT
This pullout from the 1917 photographic plate of van Maanen's star shows the element calcium. | Carnegie Institution for Science