Back in May, I posted an infographic on the Fermi Paradox. Marian Griffith, a visitor to my blog, left a wonderful comment. I was so impressed by it that I thought it deserved to be shared as a proper post. I have updated this to reflect Charles Yallowitz’s counterpoints, made in the original post’s comments.
To freshen your memory, the Fermi paradox is an argument explored by physicists Enrico Fermi and Michael H. Hart. At its most basic, it goes like this: if we, humanity, have started our attempts at space travel in the past century and are now already exploring the far edges of our solar system, and with billions of Earth-like planets in the universe, how is it that we haven’t yet encountered any aliens?
Here are Marian’s thoughts on the matter:
We don’t have the technology yet, but it is not a hard technical problem to solve to get moderately sized (for interstellar spaceships!) ship up to about 10% of the speed of light. It will just take a long while at low acceleration.
With that kind of speed, we could reach the nearest star in 50 years. Getting to the other side of our galaxy would take a couple of million years.
Life on earth was sufficiently complex 50 million years ago that intelligence /could/ have evolved. Those were, of course, the dinosaurs and they lost against a series of volcanic eruptions and an asteroid, but we can not expect that the exact same thing happens on every planet.
Which means that at least 50 million years ago somewhere in our galaxy a species might have evolved and reached the same level of technology we expect by the end of this century. The Drake equation by our current best estimates says there /should/ be some thousand intelligent species in our galaxy at this moment (and the same was true 50 million years ago). Such a species should have been able to spread across most if not all of our galaxy by now.
Even if interstellar travel is factually impossible (for which there really is no good reason to assume, it is just going to take a long time) we still should have seen by now the signs of several growing interplanetary civilisations, if only by the fact that they would have a ‘sun’ that would emit infrared radiation way below what would be possible for a sun to sustain itself.
We see neither the spread of civilisations across the galaxy nor the muted suns we must expect to see. So, where are all those intelligent species?
Marian’s Debunked Solutions
Marian feels that several of the proposed solutions to the Fermi Paradox will not actually work.
Our Wires Are Crossed goes counter to the logic of a species attempting to make contact as those would be tied in with the natural laws. We would use signals that interfere with natural phenomenon just to make it obvious it is an artificial signal.
Destroy Or Be Destroyed would have had us see these murderous aliens already at our door, as you can not really hide an interplanetary or interstellar civilization from detection.
Space Is Too Vast, They Live In Unlikely Places
Space Is Too Vast does not work either as some of the signals are about the absence of signals rather than about broadcasts. That’s what all that excitement was about last year about a sun that seemed to dim impossibly quickly, hinting at the possibility of a Dyson swarm being constructed around it.
They Live In Unlikely Places is indeed unlikely, as the laws of physics, chemistry, and biology put rather strict constraints on what life might emerge. Alternate dimensions are not likely to exist. Species that exist entirely of electromagnetic radiation can not reasonably evolve.
Here is Charles Yallowitz’s rebuttal of these points:
Space being vast can be an argument considering our ability to explore. After all, humans have explored less of the ocean than space due to our technology.
That brings me to the unlikely places. It’s entirely possible when you consider how often we find new species on our own planet. It wasn’t like they just popped up a few days before we stumbled onto them. They were living in regions that we hadn’t thoroughly explored or couldn’t get to. For all we know, there are areas of space that we can’t get a look at for a reason that we don’t realize since our technology isn’t right. I mean, we seem to think that our abilities are perfect or are on the only track to discovery, but there could be elements here that we don’t even know. Not to mention thinking that another life form out there would be even remotely similar to us, which is why I disagree with using our laws of science as unbreakable standards.
They Are Already Here
They Are Already Here is possible, but again unlikely. If you are spending thousands of years to travel here, why bother hiding? And, again, the laws of chemistry and biology dictate that any alien lifeform might find earth horribly toxic.
Again, Charles had a counterpoint:
First, if we can believe that an alien would find Earth toxic then why is it unbelievable that they would exist on a different set of scientific rules that fits their biology? This makes me think we can’t really be 100% sure of anything here and the laws are closer to suggestions. Besides, the aliens could have the tech to allow themselves to survive here.
Second, it really depends on why they are here and what they think of us. If the aliens are only interested in observing, like one does for a nature documentary, then they’d stay hidden. We’re beasts being studied, so we shouldn’t be disturbed. They would also see how violent, paranoid, and hateful we are to our own kind. That murderous alien scenario sounds more like if humans went gallivanting around space than anything else. Why reveal yourself to a species so destructive to their own kind and planet? Any intelligent alien would worry about us being a threat to them, so they’d stay hidden. Maybe they’re waiting for us to develop fast and dependable space travel, which will trigger a warning that the monsters of the galaxy are mobile.
Which leaves us with:
- Earth is a Fishbowl,
- Life is Extremely Rare,
- They use tech to spy, and
- We are the aliens.
Personally, my money is on the first one. Blub! Unless, of course, we live in a simulation anyway, in which case there’s no paradox at all!