Pluto was discovered in 1930 by Clyde Tombaugh, a 24-year-old Kansas farm boy with no formal astronomy degree, who had taught himself the sky and built his own telescopes by grinding mirrors from salvaged parts — before Lowell Observatory hired him as a young assistant to search for Planet X.

Pluto was discovered in 1930 by Clyde Tombaugh, a 24-year-old Kansas farm boy with no formal astronomy degree, who had taught himself the sky and built his own telescopes by grinding mirrors from salvaged parts — before Lowell Observatory hired him as a young assistant to search for Planet X.

On February 18, 1930, Clyde Tombaugh found a moving point of light on two photographic plates taken at Lowell Observatory in Arizona. It was not a bright object. It was not found by looking through an eyepiece and seeing a new world hanging there. Pluto entered astronomy as a small shift between images, detected by a young assistant whose job was to compare star fields until something moved. That assistant was 24 years old. Tombaugh had no astro…