Copernicus and Darwin taught us that we are not the centre of the universe. But fifty years have passed since we began listening for life in the cosmos. A billion radio channels have scanned the sky. No extra terrestrial intelligence has been found. Is it once again time to think we may be alone, and to reassess what it is to be human?

Maggie Aderin-Pocock is research fellow in UCL Department of Science and Technology Studies and an Honorary Research Associate in UCL Department of Physics and Astronomy. Since 2014, she has co-presented the long-running astronomy TV programme The Sky at Night.

Here she speaks to the IAI about the probability of finding intelligent life elsewhere in the universe, and what it would mean for mankind if we do.

The Drake equation posits that, given the vast number of galaxies and stars and possible habitable planets, there has to be intelligent life somewhere. But despite our best efforts to look, we still haven’t found any. Is this a problem?

No, I don’t think it is a problem at all, because unfortunately the probability is against us. If you look at the Drake equation and put various numbers in, after a number of experts, we come up with the possibility of five intelligent civilisations in the whole of the galaxy. The galaxy is very, very large and, even travelling as fast as we can with modern technology, to go and visit our next-door neighbour’s star, would be a journey of 76,000 years. If there is intelligent life out there, how are we going to find it? There are about 200 billion stars in our galaxy, so it’s really like looking for a needle in a haystack or a drop in the ocean.