There is a huge ‘monolith’ on Phobos, one of Mars’s moons

BBC Earth

Image: Mars Global Surveyor/Nasa

“When people find out about that they are going to say, ‘Who put that there? Who put that there?'”

These are the words of Buzz Aldrin, the second man to walk on the Moon, in 2009. He was talking about a peculiar and solitary large rock, a monolith, that sits on the surface of the Martian moon Phobos.

Aldrin was right: many people are vexed by the Phobos monolith. It has inspired all manner of alien-based conspiracy theories and this fascinating discussion on Reddit. It even gave its name to an album released this year by Les Claypool and Sean Lennon Ono.

So what is it? Read more on the BBC Earth website…