1917 astronomical plate has first-ever evidence of exoplanetary system

You can never predict what treasure might be hiding in your own basement. We didn't know it a year ago, but it turns out that a 1917 image on an astronomical glass plate from our Carnegie Observatories' collection shows the first-ever evidence of a planetary system beyond our own Sun. This unexpected find was recognized in the process of researching an article about planetary systems surrounding white dwarf stars in New Astronomy Reviews.