The International Astronomical Union has stripped Pluto of its status as a planet. Pluto fails to meet the IAU’s new guidelines for planets, mainly because its orbit overlaps with Neptune’s. Suddenly our solar system has only eight official planets.
That’s bad news for lovers of Clyde W. Tombaugh, who discovered Pluto as a self-taught 24-year-old astronomer working at the Lowell Observatory in Arizona. Remarkably, Tombaugh found Pluto by comparing photographs of the night sky again and again, looking for moving bodies among the stars.