dyson sphere
Artist impression of a Dyson SphereKevin Gill/Flickr, CC BY-SA

Professor Brian Cox has said that if an advanced alien civilisation had built a megastructure to harness energy from its star, it would not be "horrendously surprising". The physicist was speaking about the possibility of an alien megastructure around the star KIC 8462852 on Shaun Keavney's BBC Radio 6 breakfast show.

Cox said the discovery of the dimming star – located over 1,400 light-years from Earth – is nothing to be worried about, but that it certainly is an unusual find. The dimming star was found using the Kepler space telescope, which looks at planets around stars. With KIC 8462852, scientists noticed there were "huge light dips".

"A quarter of the light from the star would vanish – which even the biggest conceivable planet would only drop the light by about 1%. It's not planets that's doing it. And they're irregular and you can measure the shape - we can see it's not spherical and ... it's a very strange star system where there's something really big, or lots of big things orbiting around the star," said Cox.

There are several theories as to what is causing this massive light dip. One is that it is the result of a planetary collision, but this would have resulted in dust clouds that could be detected by the heat radiation. Another is a nearby star has disturbed the comets in the oort cloud, scattering thousands of comets around.

Finally, it could be an alien civilisation building a massive structure around the star to harness its energy. This idea was first suggested by Freeman Dyson in the 1960s, who said any advanced civilisation would need more and more energy. With the sun being the biggest source of energy, it makes sense they would turn to this and build orbiting solar panels around the star.

Cox elaborated: "It is a thing called the Dyson Sphere, which is where an ultra-advanced civilisation basically surrounds their whole star in a sphere of solar panels, which would get every last bit of energy from the star, so they could build their big space faring interstellar civilisation.

"The thing is, you think that's mad, but is it? In human universe, one of the great paradoxes – called the Fermi paradox – is that we haven't seen any evidence of alien civilisation. Given that we now know there are 20 billion Earth-like planets in the Milky Way, and there's been 11 billion years for life to arrive on these Earth's, at least a few of them would become advanced way beyond our level.

"Then you would think there should be civilisations out there that are building technology that we could see or hear with radio telescopes. But we've never seen any, and it's one of the great mysteries."

He said having built the first telescope that can look at these distant stars (Kepler), if you do find some evidence of an advanced alien civilisations then it should not be shrugged off as nonsense, but should be investigated further.

"I emphasise, it probably isn't solar panels, but it's data that isn't explained at the moment and it wouldn't be horrendously surprising if it turned out there was an advanced alien civilisation there that was way ahead of us and had built some big solar panels. I wouldn't go 'that's impossible' – it isn't – in fact I would like to say I wouldn't be surprised at all."