The search for alien life in the Universe is one of the most intriguing quests of our time.
From UFOs and little green aliens to the possibility of life in the underground aquifers of Mars, there's no end to speculation as to what form this life could take and how it could have developed.
There's even a raft of videos on the internet speculating that aliens must have visited ancient civilisations on Earth, because otherwise, how else could the Mayans have built their incredible temples.
Spoiler - there is no evidence at all for this.
Frankly, if I was a Mayan stoneworker from 250AD, I would find it deeply insulting.
But a more interesting theory, and one which has more credibility, is that of panspermia.
That life exists throughout the Universe and can be transported through space from one location to another.
Although it's certainly not proven, a team of prominent scientists from MIT and Harvard have been working on a theory that some form of life was actually delivered to Mars in this way.
Here's what we know.
Life is incredibly adaptable, just look at the way our own species has managed to thrive across the globe, and microorganisms, such as archaea and bacteria, over the course of millions of years of evolution have been able to modify themselves in order to adapt to a vast range of conditions.
