A MYSTERIOUS flash on the Moon caught on camera 50 years ago is still provoking disagreements about its origin. Astronomer Bonnie Buratti says her new results show that the flash was caused by a 20-metre asteroid hitting the Moon.
If Buratti is right, such impacts may be more frequent than thought – about once every 30 years on the Earth, and every 500 years on the Moon. But other asteroid watchers think the flash was due to a small meteor burning up in Earth’s atmosphere.
Amateur astronomer Leon Stuart’s 1953 photograph of the Moon shows a light spot near the centre of the Moon’s visible surface (see Graphic). It would take a half-megaton explosion to produce such a flash, says Buratti, of NASA’s Jet Propulsion Laboratory at Pasadena.
The resulting crater would not be visible from Earth, but it should appear on close-ups taken by lunar probes. In a future