Astronomer who discovered Pluto. ALS, one page, 8 x 10, Mesilla Park, NM letterhead, February 13, 1978. In part: “We really don’t know for sure the origin of Pluto. It may have been one of the original blobs of matter that condensed out of the initial solar system cloud. I think that Pluto may have been an interstellar tramp which passed near enough to Neptune to deflect it from its original trajectory and permitting gravitation’s capture by the sun. Thank you for your interest.” In fine condition, with small chip at top border and lower left corner. R&R COA.