The UK's top astronomer says he reckons there could be life on other planets.
Lord Rees says if there's extra-terrestrial life out there, we have a better chance of finding it now than ever before.
On Monday leading scientists and star-gazers from around the world are meeting in Britain to talk about finding life in outer space.
Lord Rees said: "I suspect there could be life and intelligence out there in forms that we can't conceive."
Scientists have been scanning the skies for radio broadcasts from intelligent life for 50 years.
So far they've only heard hissing and crackling.
But they reckon modern technology means if there is life out there, they've got a much better chance of finding it.