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Winning the E.T. Lottery
Consul writes "Space.com has a cute story about the statistical probabilities that we have been visited by an alien civilzation. He seems to make a convincing argument."
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...is that, either:
1) Faster-than-light (FTL, warp, whatever) travel is possible, and nobody's invaded us because there's some overarching federation of planets that's keeping us protected from outside influence until we're ready, and that's way cool.
or
2) FTL travel is not possible, and so nobody's coming here 'cause it's just not worth the trip. And that's depressing as hell.
Am I missing anything?
The problem with this is that analysis like this are simply interesting reading and speculation. Nothing more. Barely science and really not past the hypothesis stage (there is no evidence he is correct).
I can find good arguments for both why or why not other worlds may have life or intelligent life.
-Sean
All it takes is for someone, somewhere to build an intelligent(ish) self-replicating machine programmed to spread throughout the galaxy - one per interesting star system.
Such a system could cover the entire galaxy in a couple of million years easily (and cheaply after initial design/construction cost). They can do whatever you like; sit and watch, make contact, try to destroy any competitors (The Forge of God style; soon to become a set of movies, yay), and call home (since you end up with a network of them; sure, it'll take a while to get back home, but it's one hell of a cheap way to learn an awful lot about the galaxy).
Given that it only takes one civilization to have done this, and given that our solar system is probably quite interesting given it's layout, I wouldn't put too high odds on there NOT being such a device hanging around near here.
Or perhaps the aliens sent life-creating probes to thousands or even millions of star systems.
Imagine if we found that life is unique to Earth, but there are tons of planets out there capable of supporting life. Now we build a probe that will go to one such system. This probe determines what planet in the system has the best chance of supporting life, and it goes into orbit around it. Over time, it launches capsules with increasingly more complex life forms. This is done in conjunction with monitoring of the planet's atmosphere to encourage Earth-like development. We mass-produce said probes, and launch one to each of our neighboring star systems, expanding our definition of "neighboring" as we continue to produce the probes.
Now when we get around to colonizing the stars, we have planets ready for us.
You have a quarter in your pocket and decide to flip it in the air. It lands with the heads side facing up. You repeat this procedure, and without fail the heads side is always facing up after the quarter lands. You do this ... oh ... 10,000,000 times and every time the heads side is facing up. What is the probability that on the next throw the heads side will be facing up?
... 50%
Are you ready for the answer?
The existence of intelligent life on this planet does not necessarily imply the existence of intelligent life on other plantes. Just because a quarter lands heads up 10 million times does not imply that the next toss will produce the same result.
The existence of life on any planet must be taken as an individual probability just as each individual quarter toss must be taken as an individual probability.
QED
They spice up our water/air/primordial-soup with some pre-life cake mix and then fly away. They tell all their friends to come and visit when they get the chance, you know, just to look in and see how things are going. Well, then we get visited by aliens for the next few billions years (assume they have long life spans, or collective memories).
Seems this scenario gets rid of all of his improbable probabilities.
...And instead gives the improbable scenario of aliens stopping by tens or hundreds of millions of times over the Earth's history. This would take a significant expenditure of resources, to little end (especially since the hypothetical ant-farm alien could have seeded a barren world in their own system or otherwise closer to home for convenient visiting). It would also require lots and lots of patience and dedication that would probably be more entertainingly spent elsewhere.
In summary, I'm doubtful of this scenario.
It appears, depressingly, that modern physics is telling us that FTL travel is not possible, and never will be.
Actually, our existing understanding of physics suggests several interesting possible approaches to FTL travel. These are already being studied to some extent; time will show whether they're practical or not.
We also have enough gaps in our understanding to leave room for potential methods of FTL travel. We just know that it isn't terribly easy, if it is possible.
I think that is the most likely explanation. No civilizations make routine interstellar trips simply because it is so expensive.
That's one possibility.
Another is that life is uncommon enough that even frequent-FTL-travelling civilizations wouldn't be near enough to us to have found us.
Another is that the active lifetime of civilizations tends to be short enough that nobody happened to be alive (or at least interested in contacting people) during our history to contact us.
Or a combination of the above.
It will be interesting when we finally have enough information to be reasonably sure which is the case.
Lars T.
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