ALS, one page, 8.5 x 11, September 21, 1979. Letter to a space enthusiast mentioning his upcoming book and his discovery of Pluto. In part: “From my extensive planet search over 70% of the entire sky down to the 17th magnitude, this would indicate that other possible planets would have to be small and very distant to have escaped any thorough Blink-Microscope-Comparator…There are several hypotheses on the origin of Pluto and its satellite Charon—plausable but debatable. With the discovery of Pluto’s satellite. A reliable value for the mass of Pluto became available, with the astonishing flow mass 1/5th that of our moon. Charon’s mass is 1/10th of that. Density near 1.00 equal to that of ice!” In fine condition. RRAuction COA.
