The discovery of 1,000 smoke circles in space has given astronomers hope extra-terrestrials may be trying to contact us.
They appeared in the last year and have baffled scientists who have never seen anything like them before.
Many experts believe they could be up to 1,000 messages from an alien life form trying to get in touch.
They could also be remnants of an exploding star somewhere in the galaxy.
Others think they could be connected to wormholes – a theoretical passage through space-time that could create shortcuts to travel across the universe.
Prof Ray Norris, of Western Sydney University in Australia, said his colleague who discovered them dubbed them “WTF” because she had no idea what they were.
Prof Norris said they looked like a “ghostly circle of radio emission hanging out in space like a cosmic smoke-ring”.
He added: “None of us had ever seen anything like it before and we had no idea what it was.
“At first we suspected an imaging artefact perhaps generated by a software error. But we soon confirmed they are real, using other radio telescopes. We still have no idea how big or far away they are.
“These enigmatic blobs don’t look like anything we already know about.
“When we look in images taken with optical telescopes at the position of ORCs (odd radio circles), we see nothing.
“The search is now on with telescopes around the world to find more and understand their cause.
“Our team is brainstorming all these ideas and hoping for the ‘eureka moment’ when one of us has the flash of inspiration that solves the puzzle.”
By email@example.com (Jerry Lawton)