The search for evidence of extraterrestrial intelligence is one of the most exciting pursuits in astronomy today. Needless to say, there is a lot of controversy and debate surrounding the topic, partly due to an event which happened in 1977 – the famous “Wow!” signal. The brief but unusual radio transmission was detected only once, and the debate over its origin has continued to this day. Now, a group of astronomers are claiming to have finally solved the mystery. According to their new study just published, the signal came not from aliens, but comets.