THIS WAY OUT

EXIT NOTES Trying to separate the facts from the rumours

arlier this year, scientists announced the Ediscovery of Kepler-186f, a planet 492 light years away. It was notable as the first planet discovered that’s almost exactly the same size as Earth, orbiting in the “habitable zone” — the distance from a star in which we might expect liquid water, and maybe comparable life. It also, however, increases the probability of inevitable near-term human extinction — a concept known as the Q: WHAT IS “THE GREAT FILTER” AND IS IT LIKELY TO BE THE Great Filter. It’s a theory END OF HUMANITY AND THE REASON WE’VE NEVER MET ALIENS? that addresses the Fermi Paradox: why haven’t we met alien life, despite the existence of hundreds of suggests there’s an Hawking, have expressed is just too far away billions of solar systems in inherent destructive serious concern about the and we’re experiencing our galactic neighbourhood tendency common to exotic but understudied the streetlight effect in which life might evolve? virtually all sufficiently possibility of machine (google it). That we haven’t, advanced technological super intelligence. After all, the Voyager 1 suggests at least one of civilisations. Here on Earth The universe is 13.7 probe, in its 38th (Earth) the evolutionary steps we have survived meteor billion years old and year of travel, is now just from simple organisms strikes, super volcanoes many other planets are 18 light years away from to interstellar civilisation and naturally occurring vastly older than Earth. us, and that’s the farthest is exceedingly unlikely. pandemics for around Thousands — possibly even we’ve gone — our galaxy This is why the recent 200,000 years, and also billions — of them should alone is at least 100,000 search for evidence of life persisted through the self- sustain cultures millions light years across. on Mars is significant. As destruction of civilisations, and billions of years more Alternatively, the philosopher Nick Bostrom from the Mayans to advanced than ours. Earth silence from the stars is pointed out, “If it happened the Roman Empire and and the Milky Way are a portent of inevitable independently twice here beyond. But a total loss of relative newcomers in the doom. The biggest threat in our own back yard, it humanity hasn’t occurred. great scheme of everything, to humanity could be must surely have happened Yet. After all, we have only so why no sign of the the very progress we are millions of times across been living with things intelligent life that has this currently celebrating. the galaxy. This would like nuclear weapons for a massive evolutionary head- Perhaps life in the universe mean that the Great Filter relatively short time. start on us? is simply doomed to fail if is less likely to occur in the Huge leaps in There’s a school of it becomes too advanced, early life of planets and is technologies are occurring thought that just as the and all intelligent species therefore more likely still right now and astronomers existence of some form of become extinct before they to come.” such as Sir Martin Rees at life elsewhere is almost master the technology for So does this imply that the Cambridge Centre for mathematically certain, space colonisation. Is it every sufficiently advanced the Study of Existential given the size of the just a matter of time before civilisation will stumble Risk point to advances in universe, so the likelihood we face our own Great across a suicidal technology biotechnology as being of it having visited Earth is Filter? And what would or unsustainable trajectory? potentially catastrophic. almost nil for the very same be the odds on bucking This disturbing hypothesis Others, such as Stephen reason. Other advanced life that trend?

164 ESQUIRE DECEMBER 2014