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But the Milky Way is only 50,000 light years in radius (~ average distance between stars?). That's not much at all on a evolutionary scale. So your argument exp
by darkmighty 12y ago
But the Milky Way is only 50,000 light years in radius (~ average distance between stars?). That's not much at all on a evolutionary scale. So your argument explains why we're not currently observing an alien civilization (i.e. they would expand so close to light speed we would likely either be conquered or observing nothing -- so observing nothing is a consistent scenario). But it does not explain why no Type III civilizations (continuing with the assumption that civilizations all quickly go on to become Type III) has risen at all in the past hundreds of millions of years.
You can close that gap that via an anthropic principle by saying that if some civilization were colonizing our solar system, life on Earth would be extinguished/not possible.
- coldtea 12y ago>But it does not explain why no Type III civilizations (continuing with the assumption that civilizations all quickly go on to become Type III) has risen at all in the past hundreds of millions of years. I find the assumption about Type III at best. It's like expecting Moore's law to go on forever.
- sounds 12y agoDid you omit a word? ("Type III __ at best") I agree that a Type III Civilization is just an assumption of what direction a civilization would advance. The article does mention an alternative (they no longer care about meat space, or something similar). If we do resolve the Fermi Paradox I suspect we'll be able to express the answer simply enough to not need to bring in Type III Civilizations, the anthropic principle, etc. Note that I find nothing wrong with them as useful tools for discussion, just that the answer likely isn't one we can construct by means of logic, it must be discovered -- as in, observational astronomy. Which is what I intend to do: go out with a telescope and look at the stars. :)
- coldtea 12y ago>Did you omit a word? ("Type III __ at best") Yeah, "tenuous"! Thanks.
- quotemstr 12y agoThe OP's post rests on the Anthropic Principle. Essentially, we don't see evidence of a Type III civilization because anyone who dies is very quickly thereafter consumed by that civilization as it expands across the observable universe. It's a terrifying idea.
- darkmighty 12y agoNote those are two distinct explanations. OP's point about the speed of light explains only why we're not observing any civilization from the last 50,000 years, while the anthropic principle and the "quick, devouring species" assumption explain why no alien life exists at all in our past light cone.
- maaku 12y agoYes, and those were both my points :)