A longstanding question since the days of the Apollo program is whether or not the American flags left by astronauts on the moon are still standing. Buzz Aldrin has claimed that the flag left by the Apollo 11 mission got knocked over by the exhaust from their launch engine, but the fate of the other flags from the remaining five missions was not known.
But a new analysis of photographs taken by NASA's Lunar Reconnaissance Orbiter has solved the mystery — and the flags are still there.
To reach this conclusion, NASA scientists examined detailed images of the Apollo landing sites. Previous analyses showed what looked like shadows cast by the flags, but the researchers couldn't be entirely sure. What was needed was something more convincing, such as shadows that moved depending on the angle of light — and this is exactly what their new analysis has revealed. The photos show that shadows are circling the point where the flags are located — a strong indication that they're still standing.
The announcement was made by LROC principal investigator Mark Robinson who calls the photos "convincing". The team also confirmed Aldrin's recollection that the Apollo 11 flag got knocked down (which is the only one not standing).
What the flags actually look like, however, is still a mystery. Writing in Space.com, Clara Moskowitz explains:
"Personally I was a bit surprised that the flags survived the harsh ultraviolet light and temperatures of the lunar surface, but they did," Robinson wrote. "What they look like is another question (badly faded?)."
Most scientists had assumed the flags hadn't survived more than four decades of harsh conditions on the moon.
"Intuitively, experts mostly think it highly unlikely the Apollo flags could have endured the 42 years of exposure to vacuum, about 500 temperature swings from 242 F during the day to -280 F during the night, micrometeorites, radiation and ultraviolet light, some thinking the flags have all but disintegrated under such an assault of the environment," scientist James Fincannon, of the NASA Glenn Research Center in Cleveland, wrote in the Apollo Lunar Surface Journal.
Read the rest of Moskowitz's account at Space.com, which includes a neat video illustration of how the discovery was made.