Happy Birthday, Clyde Tombaugh!

Explanation: Today is the 109th anniversary of the birth of Clyde Tombaugh on February 4, 1906. Tombaugh is best known for the discovery of Pluto at Lowell Observatory in 1930. He is also the discoverer of 15 asteroids, a comet, and many star and galaxy clusters. A portion of his ashes are aboard the New Horizons Spacecraft.

Pluto

Image credit: Lowell Observatory Archives.