Too awesome to be a planet © NASA/JHUAPL/SWRI/Science Photo Library
Pluto was first spotted on this day in 1930 by Clyde Tombaugh, a 23-year-old astronomer at Lowell Observatory in Flagstaff, Arizona. Because it"s so far away—about 40 times as far from the sun as Earth is—scientists knew relatively little about Pluto until the New Horizons spacecraft reached it in 2015. In a flyby study, the craft spent more than five months gathering detailed information about Pluto and its moons. What did they find out? There’s a heart-shaped glacier, blue skies, spinning moons, mountains as high as the Rockies, and it snows—but the snow is red.