American astronomer (1906–1997) best known for discovering Pluto in 1930. ALS signed “Clyde W. Tombaugh, Emeritus Professor of Astronomy MNSU,” one page, 6 x 9, June 12, 1995. Tombaugh responds to an astronomer’s questions. In part, “Over a period of 14 years I searched over 2/3rds of the entire sky down to the 17th magnitude…Pluto was the only new planet that showed up. Even with the double universe square law, I would have detected a planet like Neptune at 7 times Neptune’s distance from the sun. None there! As a result, I do not think that there is a 10th planet.” Accompanied by the original mailing envelope, addressed in Tombaugh’s hand, as well as a felt tip signature on a blue card In fine condition. R&R COA.
