The Drake Equation

Post #391,052 by gcareaga 6/21/14 10:03:54 PM 6/21/14 10:04:12 PM Reply	The Drake Equation N = R() x f( p) x n(e) x f(l) x f(i) x f(c) x L N = the number of civilizations in our galaxy with which radio-communication might be possible (i.e. which are on our current past light cone); and R = the average rate of star formation in our galaxy fp = the fraction of those stars that have planets ne = the average number of planets that can potentially support life per star that has planets fl = the fraction of planets that could support life that actually develop life at some point fi = the fraction of planets with life that actually go on to develop intelligent life (civilizations) fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space L = the length of time for which such civilizations release detectable signals into space Edited by gcareaga June 21, 2014, 10:04:12 PM EDT Expand All History
Post #391,059 by a6l6e6x 6/22/14 3:25:06 PM Reply	Heard Carl Sagan explain it on stage in LA back in 1974. We've come a long way baby! At least with n(e). Too bad he did not get to see the recent developments. I don't recall a specific number, but his estimates at the time were way low. Alex "There is a cult of ignorance in the United States, and there has always been. The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that "my ignorance is just as good as your knowledge." -- Isaac Asimov
Post #391,060 by gcareaga 6/22/14 4:07:49 PM Reply	From the source I heard Frank Drake explain it in class in 1986.
Post #391,063 by a6l6e6x 6/22/14 4:53:53 PM Reply	Indeed the source! Alex "There is a cult of ignorance in the United States, and there has always been. The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that "my ignorance is just as good as your knowledge." -- Isaac Asimov
Post #391,069 by gcareaga 6/22/14 5:50:21 PM Reply	Missed opportunity When I heard the equation, it was just something else to remember long enough to regurgitate it onto an exam. I wish I had had the foresight to think to ask this question. When Drake created the equation, I think there was a mid-century assumption bias that technologically advanced civilizations would be immortal (the civs if not the constituent biologicals). What about an extinction rate? Yeah, it could be partially accounted for in L, but I think it rates its own variable. Maybe c really is a hard wall and macro-biological travel across the gulf of stars is impossible. If this is the case, home stars will will eventually die, violently or slowly in the case of the sub-fusion brown dwarves.
Post #391,070 by a6l6e6x 6/22/14 6:10:42 PM Reply	Re: advanced civilizations would be immortal I distinctly recall Sagan mentioning civilizations doing away with themselves because of some stupid act. Frankly, between folks seeking rapture and those seeking 72 virgins, it's becoming an ever more probable event. Alex "There is a cult of ignorance in the United States, and there has always been. The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that "my ignorance is just as good as your knowledge." -- Isaac Asimov
Post #391,071 by gcareaga 6/22/14 6:46:10 PM Reply	Re: advanced civilizations would be immortal It shouldn't be binary; all cigs endure or all perish. Okay, well maybe the latter, but if so what is the lifespan? Need a variable even if it is a blind guess.
Post #391,072 by Ashton 6/22/14 7:16:11 PM Reply	Thanks for reminder 'extinction rate', also that bias. Clearly noted (now!) re, in '50s: strong presumption that Techno implicitly could solve any problem ('you could parse in Boolean?' they may have meant; the smarter ones, anyway.) My 'institute' was certainly rife with such bubbly optimism. But for those not up to Drake's eqn., Sagan's audience: I thought he did a decent task of conflating such missing-parts? into that ominous phrase about (Our!) tendencies to commit seppuku in the name of any number of cockamamie rationales. (As with 'I.Q.' too..) I doubt that any number in an equation could capture such a species-wide defect, into some Probability #. Besides if that blindness tracks "IQ", we're certainly doomed to a death of un-Natural kind, anyway.
Post #391,286 by Another Scott 6/29/14 11:31:29 PM Reply	Apparently Fermi had a version, too. http://praxtime.com/2013/11/25/sagan-syndrome-pay-heed-to-biologists-about-et/ A good starting point is Stephen Webb’s book “If the Universe Is Teeming with Aliens … WHERE IS EVERYBODY?: Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life.” It’s a fun romp through the history of the Fermi Paradox. From page 23: “it was a 1975 paper by Michael Hart in the Quarterly Journal of the Royal Astronomical Society that sparked an explosion of interest in the paradox. Hart demanded an explanation for one key fact: there are no intelligent beings from outer space on Earth at the present time.” Hart’s explanation was “we are the ﬁrst civilization in our Galaxy.“ Hart’s 1975 paper is short and clear, and worth a quick read. Hart runs various scenarios, but for me the key insight is one of time scale. It takes (only) millions of years for intelligent life to completely fill the galaxy, but billions of years for it to evolve. So first out the gate should be everywhere before second out the gate. Logically if ETs exist they should be here. And they aren’t. So case closed. The Fermi Paradox literature since Hart could arguably be characterized as nonstop special pleading to avoid a common sense conclusion. I hadn't seen this argument before: And as quoted in Mark A. Sheirdan’s book, we have eminent Evolutionary Biologist Theodosius Dobzhansky (“Nothing in Biology Makes Sense Except in the Light of Evolution“) joining the fray: In his article Dobzhanksy turned Sagan’s argument on its head. Dobzhansky cited the fact that of the more than two million species living on Earth only one had evolved language, extragenetically transmitted culture, and awareness of self and death, as proof that it is “fatuous” to hold “the opinion that if life exists anywhere else it must eventually give rise to rational beings.” Now we’ve nailed it. It’s Evolutionary Biologists versus Astronomers. :-) See the original for lots of embedded links. (via Sean Carroll on G+ - https://plus.google.com/u/1/118265897954929480050/posts/PCTANMoxvb3 ) Cheers, Scott.
Post #391,597 by Ashton 7/6/14 5:02:56 AM Reply	Great material for honing the fringe of what-ifs? of more practical aims, maybe. (Speculation is that the growth to 'sentient adulthood' (after the first denizens multiply) is as iffy as right-here contemporary problems.) How do you accelerate from some basic sentient inroads towards (adult-level for that species?) Can we improve on the n-billions years postulate --from scratch/microorganisms--> to a level capable of launching asexual-reproducing robots for exploration? Or, let's go down quite a few orders-of-magnitude--you'd think that would be simpler, no? How do you get.. already well-developed creatures, most often engaged in trying to emulate kittens-at-play -vs- doing any chores, (especially assigned-ones?) like, oh say: cleaning the litter-box; then preparing for imminent days: calculated to become too-hot to be outside. (While you still can be outside.) and also too--before your common foods have also wilted ... and a few thousand other things that aren't what you wished-for. Obviously 'we' haven't the chops to solve That dilemma yet, judging by all the interest in 900 BHP 'street cars', but not even 10 min./week checking out thermodynamics' effects on personal essential-Meatware. $B Super-Ball jackpot for best MOTIVATIONAL posters!! (Super-Bargain if they work.)

Welcome to IWETHEY!