Hundreds of thousands of pictures of the moon will be examined for telltale signs that aliens once visited our cosmic neighbourhood if plans put forward by scientists go ahead. Passing extraterrestrials might have left messages, scientific instruments, heaps of rubbish or evidence of mining on the dusty lunar surface that could be spotted by human telescopes and orbiting spacecraft.
Though the chances of finding the handiwork of long-gone aliens are exceptionally remote, scientists argue that a computerised search of lunar images, or a crowd-sourced analysis by amateur enthusiasts, would be cheap enough to justify given the importance of a potential discovery.
Prof Paul Davies and Robert Wagner at Arizona State University argue that images of the moon and other information collected by scientists for their research should be scoured for signs of alien intervention. The proposal aims to complement other hunts for alien life, such as the Search for Extraterrestrial Intelligence (Seti), which draws on data from radiotelescopes to scour the heavens for messages beamed into space by alien civilisations.
"Although there is only a tiny probability that alien technology would have left traces on the moon in the form of an artefact or surface modification of lunar features, this location has the virtue of being close, and of preserving traces for an immense duration," the scientists write in a paper published online in the journal Acta Astronautica.