DISCOVERING alien life before the year 2038 is a "realistic" possibility, according to a top British scientist.

A new report argues that the "necessities of life" – like water and energy – are so "common in the Solar System", that it's possible we're not alone.

Dr David L Clements, of the Imperial College London, has published a new paper detailing the possibility of "intelligent, interstellar travelling and colonising life".

The professor admits there it's possible our own galaxy "may be filled with life" – but says that tracking it down is very difficult.

In a new paper, Dr Clements explains that "most potential sites are beneath the icy surfaces of gas giant moons".

"If this is the case elsewhere in the Galaxy, life may be quite common but, even if intelligence develops, is essentially sealed in a finite environment, unable to communicate with the outside world," the paper explains.

The paper details how these moons may contain life – but it would be buried deep, and evidence is unlikely to have escaped into the wider universe.

"The conclusion of this analysis for our own Solar System is that the interior of the icy moons may be where the bulk of life in the Solar System is to be found," said Dr Clements.

"However, this life, intelligent or otherwise, would be locked beneath many kilometres of solid ice."

He adds that this life would only "escape into the broader universe" if there were to be "catastrophic geyser eruptions, such as those found on Enceladus and Europa".

Space agencies plan to further explore these icy moons, but their size and the depth of the ice makes finding life enormously difficult.

"We are left with the rather chilling prospect that the galaxy may be filled with life, but that any intelligence within it is locked away beneath impenetrable ice barriers, unable to communicate with, or even comprehend the existence of, the universe outside," the paper explains.

This won't always be the case, however.

"Until recently, detecting signs of life elsewhere has been so technically challenging as to seem almost impossible," writes Dr Clements.

"However, new observational insights and other developments mean that signs of life elsewhere might realistically be uncovered in the next decade or two."

Dr Clements' paper is based around the Fermi Paradox, a famous contradiction posed by physicist Enrico Fermi.

Fermi suggested that the enormous size of the universe – and the billions of Sun-like stars in the galaxy, and their planets – makes it highly likely that there is intelligent life out there.

Some of these civilisations may have developed interstellar travel.

But Fermi also noted that there's a severe lack of evidence for life on other planets.

The chances of aliens being able to reach us are high, but there's no evidence that aliens ever have.

This paradox has baffled scientists for decades.

But as Dr Clements notes, it's possible life is out there – but buried so deep that we've yet to find it.

Do you think we'll ever find hard evidence of alien life? Let us know in the comments!