SETI again

On Jul 20, 2006, at 21:05 UTC, Xenophile wrote:

> Hi. I'm an Australian Aborigine in the year 1500. And I can't help
> but wonder: If there are people beyond Australia, where are they?

That's an invalid analogy, because all people got started at the same time. Sure, if all civilizations in the galaxy got started at the same time, then it would be quite reasonable to imagine that we're all at a pretty close level of development, and there would be thousands of civilizations out there who had not yet colonized the whole galaxy -- just like Star Trek.

But real life is not like Star Trek. Any natural process involving lots of random-ish variables ends up following a normal distribution. We know it took us about 4 billion years to appear on Earth, so we're talking about a distribution with a mean measured in billions of years. Unless the standard deviation is ridiculously, unbelievably small, that means that the first civilizations arose billions of years before the average. And as I'm sure you know, it only takes a few hundred million years for the first civilization to colonize the galaxy. (And this is ignoring the fact that some stars are much older than ours, which would make the argument even stronger.)

The closest your analogy could get to accuracy would be: I'm an Australian aborigine in the year 4000. Am I still wondering about life outside of Australia?

Best,
- Joe

>
Joe Strout -- joe@...