The Arecibo Message
In 1974 astronomers beamed a picture message at a star cluster 25,000 light years away. It won't arrive for 25,000 years.
What was reported
On 16 November 1974, at a ceremony marking an upgrade to the Arecibo radio telescope in Puerto Rico, astronomers transmitted a short radio message towards the star cluster M13. Designed by Frank Drake with Carl Sagan and others, it was made of 1,679 binary digits.
Arranged in a grid of 73 rows by 23 columns, the digits form a simple picture: the numbers one to ten, the chemistry of DNA, a human figure, the solar system and the telescope itself.
Explanations offered
It was mainly a demonstration of what the telescope could do rather than a serious attempt at contact. The message will take about 25,000 years to reach M13, by which time the cluster will have moved. The Arecibo telescope itself collapsed in 2020.
- When
- 16 November 1974
- Where
- Arecibo Observatory, Puerto Rico
- Witnesses
- Astronomers at the dedication ceremony
- Status
- Explained
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.