Aliens could be spreading from planet to planet like a relentless plague, hitching rides on meteorites and ‘infecting’ new worlds like an epidemic on Earth.
But if they are, we can spot them, experts believe.
The idea of alien life spreading like ‘seeds’ on the wind isn’t new - the theory is known as ‘Panspermia’.
But a new paper from experts at the Harvard-Smithsonian Center for Astrophysics suggests that if like is ‘spreading’ through the universe in this way, it will form patterns that we could see.
Lead author Henry Lin said, ‘'In our theory, clusters of life form, grow, and overlap like bubbles in a pot of boiling water.
'Life could spread in a pattern similar to the outbreak of an epidemic'
The pattern could be visible to our telescopes, Lin claims.
Lin says, ‘'Any species which acquires panspermia abilities will have enormous fitness advantages.
'Just as viruses evolved to brave the 'harsh' environment of 'inter-host' space to harness the energy of multiple biological hosts, perhaps evolution has or will drive a class of organisms to brave the harsh environment of interstellar space to harness the energy of multiple stellar hosts.'