Posted on 12/17/2002 2:21:52 PM PST by Polycarp
This is a very interesting graphic that shows the extent to which we've searched the universe for alien civilizations. Earth-like radio emissions represent the bottom edge of the graph; as you can see, we haven't even begun to search for them. As for civilizations that have transmitters the size of our largest dish (Arecibo) transmitting directly at us, we've only searched thoroughly out to about 100 light years. The galaxy is 100,000 light years across, and we live in a portion of it that is somewhat more rarefied than average.
[For reference, a "Type I" civilization would be roughly capable of transmitting a signal equivalent to all of the sunlight striking the Earth, 2x1017 Watts. A "Type II" civilization would be roughly capable of sending a signal equivalent to the power of the sun, 4x1026 Watts. (I believe the canonical signal limits for these civilizations are given as 1016 Watts and 1026 Watts.)]
After umbrella shoes (which were supposed to let you float down from high windows in buildings), there really wasn't much point in going any further!
I know the Trekkies will flame me, but Star Trek is much more fiction than science fiction.
Some folks think the collision that created the moon also created the early atmosphere and conditions that made the start of life possible -- a rare if not unique event.
Also, the size of the moon stabilizes the earth's rotation on its axis, making seasons relatively stable -- a major factor in the particular history of life on earth.
I'm betting that planets with our particular history are rare, and I'm speculating that life without our particular history will be "primative" if it exists at all.
I tell you flatly that I've never met a SINGLE physicist who has maintained anything of the kind. I did once meet a chemist who said this, and I found it shocking. I have met several laypeople who have held this belief.
I believe that a complete and correct theory of particle physics is possible in my lifetime. That is not to say that a complete and correct theory of anything means that there is nothing left to learn about it, or nothing left to invent with it. In fact, having a good understanding of something is often a prerequisite to doing something really useful with it.
I'm sure that if we are not Number One, our generals will soon have a plan to make us number one. Since we will, no doubt, all be Muslims in a few decades, we will have at our disposal the Theologically Guided Missile.
But is life (as we know it) possible in the denser portions of the galaxy?
I myself am not wedded to carbon-based, cellular life forms, if that's what you mean. I see no reason to posit that a civilization is more likely in a place where we ourselves would be more comfortable. Besides, if we found an intelligent signal in the "dead zone", we wouldn't disregard it on the grounds of location.
It's worse than you paint it. Look at all the scientists who are flaming lefties. Stephen Hawking thinks that Al Gore would have made a good President.
I read Fred Hoyle's Black Cloud many decades ago, and have never considered our life forms the only ones possible. However, I'll believe in the reality of alternatives when we see them. In the meantime, back on earth, I will not be shocked if my great-great grandchildren have minds made of transistors. Surprised, but not shocked.
That's no biggie, since we were already deep into believe-it-when-I-see-it territory the moment we started talking about extraterrestrial civilizations.
In the meantime, back on earth, I will not be shocked if my great-great grandchildren have minds made of transistors.
And I'll be downright disappointed if I can't get myself one of those, someday.
And yet, your new baby could easily pass as terrestrial.
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