Dexter, Hillsdale and the "swamp gas"
The account
On two nights in a row, Michigan residents and students saw lights hovering over swamps, and the official explanation became a national joke.
What investigators found
Astronomer J. Allen Hynek suggested burning swamp gas as a possible explanation; the uproar helped bring about the Condon Committee.
The story
On March 20, 1966, farmer Frank Mannor and his family, near Dexter, Michigan, reported colored lights over a swamp close to their home, and police officers called to the scene saw lights as well. The next night, dozens of students at Hillsdale College, about a hundred kilometers away, described a glowing object moving over a marshy area near campus.
Sent by the Air Force, astronomer J. Allen Hynek said at a press conference that some of the reports might be swamp gas igniting on its own. The phrase was ridiculed by the press, and Congressman Gerald Ford of Michigan called for hearings in Congress. The pressure led the Air Force to commission the University of Colorado study known as the Condon Committee. Hynek later said his explanation had been misunderstood.