"Alien" signal arrives from Mars

Could you decode a mysterious message from space?

On 24 May, radio dishes around the world received a mystery-coded signal from Mars. If this message had been a real signal sent by aliens, it would have been the biggest event in human history. However, the signal was sent by humans as a practice run, to see how hard it might be to decode a real alien message.

The project, called A Sign in Space, involved a signal being sent from a human-built satellite orbiting Mars called the ExoMars Trace Gas Orbiter (TGO). A Sign in Space was organised by the California-based SETI Institute. SETI stands for the Search for Extraterrestrial Intelligence – a field of astronomy that looks for signs of intelligent beings in space. So far, Earth is the only planet known to be home to intelligent life, but there are billions of other worlds in our galaxy.