I heard the people from the Search for Extraterrestrial Intelligence on the radio this morning. It’s not a German techno outfit. It’s a real American scientific research centre looking for intelligent life in the universe. It’s exciting. I can’t imagine the hoo-hah if they found something. It might even push Masterchef below the fold.
There could be life in the universe, for sure. But they’re dreaming if they think it will communicate with us. A few reasons:
1. You could yell at a wombat, or put the Herald Sun in front of a rose bush, but you’re unlikely to hear anything back. And these creatures share our ecosystem. Our cousins in the stars might be frantically semaphoring us and we’d have no idea.
2 Are we alone in the universe? I say we are not.
I once read a stupid argument against the existence of other life in the universe. It said that given the age of the universe, if life were common, it would have already spread around and found us. The idea is something called a ‘Von Neumann probe‘. You build a self-replicating probe, that goes out as far as it can, then builds a factory that produces new probes that go on.
They figure that if a Von Neumann probe had ever been produced in the milky way, it would take only half a million years to fill up the galaxy. We haven’t seen one land yet – ergo we must be alone in the universe.
They imagine a big titanium Von Neumann probe. Stupid boffins. A physicist called Robert Freitas says it would need to weigh 453 tonnes. Highly theoretical, tough to engineeer, prone to shedding its heat shield. But put on your lateral thinking goggles and imagine a Von Neumann probe made of something else.
I’m thinking DNA. And rather than using its own rockets, it relies on the universe’s own natural propulsion. Whenever a big meteor hits a planet covered in life, some DNA is spat out and careers across the big empty spaces until it hits another planet. Where it self-replicates like a virus.
It’s our planet-centric brains that make us assume that every step in the evolution happened here on earth. The first step in the production of life – creating DNA – is the most unlikely, so I prefer the idea that it happened once in the history of the universe, rather than it happening once in the history of the planet…
DNA is next to impossible. Cells are implausible. Plants and animals are very unlikely. For every planet lucky enough to get smeared with DNA, maybe one in a million gets sentient beings. Of those, a tiny proportion are going to get life forms smarter than your cat.
3. Despite a universe most-likely crawling with DNA, we are highly unlikely to find intelligent life. Can we imagine a world without baboons, or freshwater crocodiles? Easily – no single species defines life on this planet. Then why can’t we imagine a world without people? Homo Sapiens Sapiens is just one species.
4. And intelligence is yet to prove it can survive.
Intelligence isn’t necessarily the only necessary component for interplanetary communications. Resilient intelligence is important. If the earth has been around for 24 hours, we’ve been around for the last minute, and our ability to produce radio signals has been around for the last fraction of a second.
Our period as the undisputed bosses of this planet really only stretches back to the industrial revolution. That’s a puny 150 years. They’ve been running SETI since 1960. And we can’t even guarantee it will survive another 50 years. So the odds of our period of looking coinciding with another intelligent life-form’s period of looking has to be basically zip. Maybe resilient intelligence is a contradiction in terms. Maybe it’s no surprise that there’s only one intelligent species on earth…
The sort of intelligent life that can invent communications might also tend to destroy itself. If we’d worked a bit faster on nuclear and a bit slower on radio, we might have wiped ourselves out before we had the chance to communicate with anyone. There’s a very strong chance we’ll run out of steam long before we engineer a 453-tonne Von Neumann probe.
Or, maybe the chances of life evolving to smartness on a planet is really low because, in the interim, chances are said planet will get smashed by another asteroid.
But if the little green men do arrive before we get crunched by a space rock, I for one welcome our extraterrestrial overlords :)
Thoughts? Alternative hypotheses? Red Dwarf quotes? Can you explain the Fermi Paradox? Share it all below…