Tombaugh's Lights

The man who discovered Pluto saw something he said had never appeared before or since. Clyde Tombaugh was in his back yard in Las Cruces with his wife and his mother-in-law on the evening of 20 August 1949. A geometric group of six to eight rectangular lights like lit windows slid silently across the sky in a few seconds. The lights seemed fixed to a faint body behind them. In the archive's telling it was a cigar-shaped craft with window-like apertures moving over the desert, and Tombaugh believed it was extraterrestrial.

What is on the record

The archive's three claimants are Tombaugh, Mrs Tombaugh and a family member. The published record names his wife as Patricia and the third witness as his mother-in-law.

The archive's single telling needs two corrections. The cigar with windows is Frank Edwards's framing of the case. Tombaugh described rectangular lights and not a cigar. The telling's claim that he took it for an extraterrestrial craft also sits uneasily with the record. Tombaugh himself suggested the lights could be a reflection off an inversion layer in the atmosphere. Donald Menzel gathered his statement and published it with Boyd in 1963, and Menzel also argued for a reflection. Others have proposed birds such as plovers lit from below by the lights of the town.

Tombaugh later headed the Army's search for near-Earth satellites at White Sands. The archive links three documents to the case from the CIA's FOIA collection and the Project Blue Book files. All three are classed as reporting rather than as a primary record of the sighting.

Why it sits where it does

The L3 grade rests on three claimants who are one family on one evening, and all three come through a single video. The case's weight is its witness, a professional observer of the night sky. The leading explanation on the record is his own and it is a suggestion rather than a finding. What crossed the sky over Las Cruces is not resolved here.