Professor Brian Cox's Human Universe series on BBC2 is premised on the assertion that humanity is the only advanced technological civilisation in our galaxy (the Milky Way).
He explains that two freak occurrences - the initial merging of two cells and the meteor that wiped out the dinosaurs - led to human domination of the planet and theoretically the galaxy.
It's a dizzying thought. There are billions of planets out there, surely there must have been a second genesis?
But we must be careful because the story of life on this planet shows that the transition from single-celled life to complex life may not have been inevitable.
- Brian Cox, Human Universe
Maybe the title of the show is misleading, because people have been misinterpreting Prof Cox's words and reporting that humans are truly and utterly alone in the universe.
In another tweet Prof Cox clarified the nuances of distinguishing between civilisations and life; and the universe, which is theoretically infinite, and our galaxy, which is finite.
So in conclusion, we are extremely likely to be the only advanced technological civilisation in the galaxy because of a series of events the chances of which were infinitesimally small, but that doesn't discount the fact that simple organisms (ie life) could be found on the billions of planets in our galaxy... or that other more advanced life-forms exist in the infinity of the universe.
PS We hope this is OK Brian and we don't get an angry tweet.
PPS We feel partially responsible for the initial angry tweet.
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