Panspermia - Wikipedia, the free encyclopedia
Read to your heart's content. This was controversial 10 years ago, but it's really not controversial today. It's really more of a question of if it did happen, not if it can happen.
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Panspermia - Wikipedia, the free encyclopedia
Read to your heart's content. This was controversial 10 years ago, but it's really not controversial today. It's really more of a question of if it did happen, not if it can happen.
Anyone interested in the Fermi Paradox will enjoy this interactive visualization, which allows you to tweak the parameters of the Drake Equation and calculate the number of civilizations in our galaxy capable of communication.
The most interesting perspective related to the Fermi Paradox that I've ever come across has to be this article by Nick Bostrom. To summarize very briefly, Nick argues that if we find life on Mars, or some other planet, this would be very bad news for the human race, as evidence of the distinct emergence of life elsewhere in our solar system would suggest that life is not rare at all in our galaxy, which in turn suggests that the asnwer to the Fermi Paradox probably has something to do with advanced civilzations inevitably destroying themselves before they develop the technology to traverse the galaxy.
That doesn't follow at all. That conclusion only makes sense if you assume that civs get stuck at approximately the same technological level as modern humans, and that they broadcast, and that they broadcast on frequencies we listen to (hint: SETI doesn't listen in the FM band...why?)
I don't see how those assumptions are built in to the argument. The main assumption is that the great filter (defined here, scroll down a bit) exists.
The Fermi "Paradox" is based on the assumption that if intelligent life is common, then we should have heard from them by now. There are plenty of very solid reasons why that is an absurd notion, some of which appear in this very thread. So there's no reason to suspect that intelligent life is rare, hence no reason to postulate any sort of "filter".
Gotcha. You're saying that there really isn't a paradox here. That's an interesting alternative, and it certainly can't be ruled out. However I don't find it as compelling as the more conventional filter model, and I'll take a stab at explaning why.
If there are no filters, we would expect the galaxy to be swarming with intelligent life. Even if many of these intelligent civilizations possess communication techniques or colonization technology too advanced for us to even recognize (i.e because of nanoparticles as you suggested in a prior post), it doesn't have to be the case, and I might go so far as to say probably wouldn't be the case, that EVERY single one of these intelligent civilizations converges on methods that we lack the ability to detect. It would only take one intelligent civilization that sends out macroscopic von Neumann probes, or conventional radio waves, that reach earth and render the fermi paradox moot.
Can you imagine humans communicating via radio a million years from now? If not, then I would ask why you're assuming that aliens are so much dumber than us that they'd get stuck at, conveniently, the exact level of technology of 21st century Earth. It's silly. But even if one or two civs do stay at that level, then we'd almost certainly not hear from them. The galaxy is a big place, and to hear radio waves after such a short time of listening (and that's assuming SETI were even listening in the correct band, which it is NOT), is very unlikely. As a general rule of thumb, if such civilizations are thousands of lightyears away, we'd probably need to listen for thousands of years to detect them, statistically speaking.
As for von Neumann probes, I would ask you how you know that they're not here already? Earth is geologically and biologically active. Anything that arrived more than a few thousand years ago would be undetectable unless you knew precisely where to look. And you casually toss aside the notion that they might be microscopic, yet you provide no reasoning as for why that wouldn't be the case.
But, you might argue, such a probe would intentionally be designed to be detected by us. But now it's you who are making a strong assumption about the motives of the aliens, by assuming that they care about making contact with us. Keep in mind, anyone more than about a hundred light years away probably doesn't even know we exist.