When Apollo astronauts visited the Moon in the 1960s and 70s, they reported seeing a strange glow all along the horizon just before sunrise. This enigmatic light show has evaded explanation ever since, but a NASA mission set to launch this week could solve the mystery once and for all.
NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) is an unmanned mission that’s scheduled to launch on a Minotaur V rocket this Friday (6 September). It’ll take around 30 days to make it into orbit around the Moon, before spending 100 days probing the Moon’s atmosphere with its onboard instruments.
The Moon’s atmosphere is much thinner than the Earth’s and is usually considered to be a vacuum. However, scientists believe that this ethereal atmosphere may contain lunar dust that’s become charged by ultraviolet radiation from the Sun and propelled skywards. One aim of the LADEE mission is to find out whether sunlight scattering off the airborne dust can explain the mysterious glow sighted by astronauts over 40 years ago.
LADEE is a reminder that just because we’ve sent the Curiosity rover to Mars, it doesn’t mean we know everything about our nearest celestial neighbour.