The Glow of Aristarchus
For centuries, astronomers have reported glows, flashes and hazes on the Moon, most often at one bright crater.
What was reported
Transient lunar phenomena are short-lived lights, colours and hazes that observers have reported on the Moon's surface. In 1787 the astronomer William Herschel described glowing spots he took for volcanoes. A NASA catalogue from 1968 listed hundreds of such reports, and about a third of them came from the bright young crater Aristarchus.
In July 1969, Mission Control asked the Apollo 11 astronauts, orbiting the Moon, to look at Aristarchus. They reported that an area near it seemed to be lit up more than the rest.
Explanations offered
Suggested causes include gas escaping from beneath the surface, small meteorite impacts, and dust lifted by static electricity. Sceptics point to tricks of Earth's atmosphere and of eyesight, and to Aristarchus simply being the brightest spot on the Moon. Telescopes now watch for flashes, and impact flashes have been confirmed, but the glows remain unexplained.
- When
- Reported since the 1700s
- Where
- Aristarchus crater, the Moon
- Witnesses
- Astronomers, and the crew of Apollo 11
- Status
- Unexplained
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.