The Day America Listened for Mars
When Mars came closer to Earth than it had in a century, the United States asked its radio stations to fall silent, so it could listen.
What was reported
In August 1924, Mars came closer to Earth than at any time in almost a century. Many people still thought the planet might be inhabited, and the astronomer David Todd persuaded the US government to listen for signals. A 'national radio silence' was proposed, asking stations to go quiet for five minutes every hour, and the Navy told its powerful radio stations to listen.
The Army's chief codebreaker was ready to translate any message. An inventor named Charles Francis Jenkins built a machine to record radio signals on a strip of film, and the result showed a strange pattern of dots and dashes, which some newspapers described as a crude face.
Explanations offered
No signal from Mars was ever identified. The marks on Jenkins's film were almost certainly radio interference or ordinary stations. We now know Mars has no civilisation, but the episode was one of the first organised attempts to listen for life elsewhere, decades before modern SETI.
- When
- 21–23 August 1924
- Where
- US Naval Observatory, Washington, D.C., USA
- Witnesses
- US Navy and Army radio stations, astronomers and the public
- Status
- Nothing found
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.
More from Maryland