An undergraduate class for non-astronomy majors at the University of Maryland has made a rare discovery that even the pros missed: a pair of asteroids that orbit and regularly eclipse each other located in the main asteroid belt between Mars and Jupiter. The rocky duo collectively known as 3905 Doppler is one of less than 1000 known eclipsing binary asteroids. The object was first found in 1984 but given little thought until this classroom of students chose it and a couple other asteroids to monitor. That’s when they realized that one was actually two sometimes eclipsing one another. One student said it was “extremely frustrating” at first because they couldn’t figure out why the asteroid’s light curve didn’t look right. As it turns out it was the two asteroids orbiting one another, and occasionally blocking the each other’s light.