The Flashes on the Moon's Dark Side
On the dark part of the Moon, tiny points of light flash for a fraction of a second, then vanish. In 2013, one was bright enough to see without a telescope.
What was reported
For centuries, observers reported brief flashes of light on the Moon, which were usually dismissed. Since the 1990s, video cameras have shown that they're real: on the Moon's unlit part, points of light flash and disappear, lasting a fraction of a second.
On 17 March 2013, NASA cameras recorded a flash in Mare Imbrium about ten times brighter than any seen before. Later, the Lunar Reconnaissance Orbiter photographed the spot and found a fresh crater, about 18 metres across, that hadn't been there before.
Explanations offered
The flashes are meteoroids, small rocks from space, hitting the Moon. With no atmosphere to slow them, they strike at tens of kilometres per second and the impact makes a brief burst of light and heat. The 2013 rock was probably about 40 centimetres wide. Studying the flashes helps work out the risks to future Moon bases.
- When
- Brightest recorded on 17 March 2013
- Where
- Mare Imbrium, on the Moon
- Witnesses
- NASA and amateur astronomers
- 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.