Why Haven’t We Found Life Elsewhere In The Universe?
As one of the contributors to this book commented, something like half of the internet is devoted to the subject of UFOs, extra-terrestrials and the conspiracy theories that surround them. So surely it is time for a serious scientific look at the subject. In this book, I have gathered together my dream team of alien experts from a diverse range of fields: cosmology, astrobiology, chemistry, psychology, philosophy and mathematics, not to mention experts on the way we have portrayed aliens in popular culture and what it would mean if we ever did discover that life existed elsewhere. Let me wet your appetite.
During a lunchtime chat with colleagues at Los Alamos National Laboratory in New Mexico in 1950, the physicist Enrico Fermi posed a simple question about the possibility of extra-terrestrial life. ‘Where is everybody?’ he asked, only half-jokingly. Today this is known as the Fermi paradox. His point was that since the age of the Universe is so great and its size so vast, with more stars out there than there are grains of sand on all the earth’s beaches, surely life must exist somewhere else. Indeed, since we now know that many, if not most, stars have their own planetary systems, then the cosmos should be seething with of life, including intelligent species advanced enough to have the knowledge and technology necessary for space travel. So, never mind the odd flying saucer conspiracy theory, why isn’t the earth the destination, whether for invasion or just a holiday, of countless ETs?
Fermi’s paradox is of course easy to resolve. Maybe the distances required for interstellar travel are just too great, or no one has got around to us yet. But, they wouldn’t need to visit us physically. We should still be able to detect the existence of technologically advance alien civilisations even if they never leave their home planet. After all, for the past hundred years or so, we have been announcing our presence to any listening aliens advanced enough and close enough to us. Ever since we invented radio and television, we have been radiating our electromagnetic chatter into space.
For over fifty years, astronomers have been listening out for signals from space using radio telescopes. The search for extraterrestrial intelligence (or SETI) began with the pioneering efforts of Frank Drake, a man famous for coming up with a simple equation that bears his name and which provides an estimate of the likelihood that alien intelligence exists somewhere else in the Universe. He argued it was a big number. Recently, the announcement that SETI will invest $100 million in the quest to discover intelligent life elsewhere in the Universe has captured the public’s imagination around the world.
Other academic research has focused on the planets and moons themselves that might host life. Today, hunting for extrasolar planets is one of the hottest areas of scientific research, and with bigger and more powerful radio telescopes at their disposal astronomers are discovering new potentially habitable stars on a regular basis. But we also need to understand how likely it is that life could evolve elsewhere given the right conditions. And to answer that we need to understand how life began on earth. So there is a lot going on.
So what is the conclusion my Team Aliens and I reach at the end of the book? Well, I would say…watch this space…
Jim Al Khalili OBE is a professor of physics and the public engagement in science at the university of Surrey.
He can be found here.