Top Document: [sci.astro] ET Life (Astronomy Frequently Asked Questions) (6/9) Previous Document: F.03 What is the Drake equation? Next Document: F.05 Could we detect extraterrestrial life? See reader questions & answers on this topic! - Help others by sharing your knowledge Steve Willner <swillner@cfa.harvard.edu> One of the problems that the Drake Equation produces is that if you take reasonable (some would say optimistic) numbers for everything up to the average duration of technological civilizations, then you are left with three possibilities: 1. If such civilizations last a long time, "They" should be _here_ (leading either the the Flying Saucer hypothesis---they are here and we are seeing them, or the Zoo Hypothesis---they are here and are hiding in obedience to the Prime Directive, which they observe with far greater fiqdelity than Captain Kirk could ever muster). -or- 2. If such civilizations last a long time, and "They" are not "here" then it becomes necessary to explain why each and every technological civilization has consistently chosen not to build starships. The first civilization to build starships would spread across the entire Galaxy on a timescale that is short relative to the age of the Galaxy. Perhaps they lose interest in space flight and building starships because they are spending all their time surfing the net. (Think about it---the whole point of space flight is the proposition that there are privileged spatial locations, and the whole point of the net is that physical location is more or less irrelevant.) -or- 3. Such civilizations do not last a long time, and blow themselves up or otherwise fall apart pretty quickly (... film at 11). Thus the Drake Equation produces what is called the Fermi Paradox (i.e., "Where are They?"), in that the implications of #3 and #2 are not terribly encouraging to some folks, but the two flavors of #1 are kinda hard to come to grips with. An alternate version of 2 is that interstellar travel is far more difficult than we think it is. Right now, it doesn't seem much beyond the boundaries of current technology to launch "generation ships," which amount to an O'Neill colony plus propulsion and power systems. An alternative is robot probes with artificial intelligence; these don't seem so difficult either. The Milky Way galaxy is well under 10^5 light years in diameter and over 10^9 years old, so even travel beginning fairly recently in Galactic history and proceeding well under the speed of light ought to have filled the Galaxy by now. (Travel very near the speed of light still seems very hard, but such high speed isn't necessary to fill the Galaxy with life.) The paradox, then, is that we don't observe evidence of anybody besides us. User Contributions:Top Document: [sci.astro] ET Life (Astronomy Frequently Asked Questions) (6/9) Previous Document: F.03 What is the Drake equation? Next Document: F.05 Could we detect extraterrestrial life? Part0 - Part1 - Part2 - Part3 - Part4 - Part5 - Part6 - Part7 - Part8 - Single Page [ Usenet FAQs | Web FAQs | Documents | RFC Index ] Send corrections/additions to the FAQ Maintainer: jlazio@patriot.net
Last Update March 27 2014 @ 02:11 PM
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