A TedEd by Chris Anderson
There must be planets with life in our vast universe, right? So, why can’t we see them. This was explored by Enrico Fermi 1950. The Kepler space observatory has found hundreds of planets nearby in just the last year. If we multiply the data, that means there could be half a trillion planets in just our galaxy. If just one in 10,000 supports life, that’s 50 million potentially inhabited planets. So where are they? Our planet formed 9 billion years after the Big Bang, which means many other planets should have formed before ours and allowed life a chance. If a few of them had grown into intelligent civilizations, they would have had millions of years to advance technologically. We’ve seen time and time again on Earth that progress can take as little as 100 years. This means that any intelligent life form would have spread out, created interstellar spaceships, or at least emitted some sign of their presence through electromagnetic waves. There are many theories as to why we can’t see this. First, one super-intelligent species could have taken over the universe and imposed radio silence to blot out any potential competitors. Or perhaps intelligent life is far rarer than we think, and we are truly alone. Or, perhaps advanced life can’t control its own technological advances and obliterates itself. But there are more hopeful answers. First, we are spending very little on the search, and not looking very hard. Very few stars have truly been searched for interesting signals. We could be looking at the wrong signal, too. Intelligent life could have discovered a way to transmit through dark matter, which accounts for most of the universe’s mass. Or, aliens might have converted to life on a microscopic scale because life is better that way. There are also many experiments on Earth trying to create life from scratch. Either way, the search for life continues. Who knows? Maybe we are all alone.
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