Astronomers working at the Arecibo radio telescope in Puerto Rico have detected a weird radio signal, spotted when pointing their telescope at the nearby star Ross 128.
They're not getting too excited about the prospect of an alien civilisation contacting us just yet though.
'In case you are wondering, the recurrent aliens hypothesis is at the bottom of many other better explanations,' said Abel Mendez, the scientist leading the campaign.
Of course, this doesn't stop others speculating that the signal may be just that.
And it begs the question, how do you work out if a strange signal from space really is a message from aliens?
The simple answer is that you have to rule out everything else first and only then can you think it may be aliens.
As Sherlock Holmes said: 'When you have eliminated the impossible, whatever remains, however improbable, must be the truth.'
But eliminating all the other possibilities isn't exactly easy.
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