Re: Habitable Planets: was Notes on Uplift
Trent Shipley wrote: Ok. But it's better to go back and set the Drake factors based on what we want to get in the end. Excellent idea! And then we can get back and estimate how many planets developed pre-sentient life _before_ the Progenitors came and destroyed their own planets causing self-extinction, based on the estimation that the Universe is some tens of thousands of millions of years old and that Galaxies might have existed from half to 1/10 of this time. N* = 100*10^9 (that is, 1.00E+11) fp = .75 (most systems have planets) ne = .25 (few could support life, partly a cheat factor) fl = 3.00E-05 (3/100,000 have life, entirely a cheat factor. Implies there are a lot of terraforming candidates) fi = 1 (ALL good planets get colonized) fc = 1 (If colonized, the setlers participate in O-2 Civ.) fL = .125 (7 times out of 8 a planet is fallow) This gives the number of planets that could *naturally* support life in the Milky Way N = 7.03E+04 Small, isn't it? 5 galaxies Total natural planets under GIM control = 2.81E+06 Total natural GIM leased planets = 5N = 3.52E+05 Natural/Terraformed = 1/6 Total GIM planets (B or C leasable) = 1.69E+07 (We don't count A class leases because they are in need of terraforming.) Total GIM B or C leases at present time = 2.11E+06 Giving us about 11.1 planets per race, which is close enough to 10. Yes, I think the mean of 10 is consistent with the data that Earth has 10 Alberto Monteiro ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: Habitable Planets: was Notes on Uplift
On Friday 2004-01-09 05:34, Alberto Monteiro wrote: Trent Shipley wrote: If there are 2M inhabited planets then there are 14M fallow planets. At any given time there must be a total of 16M habitable planets. Ok, 700ky, or 1My, don't change the final numbers very much -Total O-2 habitable planets now --- leased:fallow --- natural:terraformed --- proportion of A, B, C and homeworld leases. --- Mean number of planets per citizen race --- fairness in distributing leases. I also think we came to some figures here. 2M *leased* planets, about 10 per citizen race. No comments on the ratio of terraformed to natural or what kinds of leases. With regard to planets I visit: http://www.activemind.com/Mysterious/Topics/SETI/drake_equation.html Some of the factors in Drake's equation are still _extremely_ innacurate. N = N* fp ne fl fi fc fL N: communicating life. N*: number of stars, site suggests 100 * 10^9 for Milky Way alone fp: fraction of stars with planets Seems close to 1 :-) ne: number of planets where life can exist Seems close to 1/10^11 :-) fl: fraction where life evolves fi: fraction were intelligent life evolves fc: fraction that can and do communicate fL: fraction of timewhere communicating civilization exists Galactics will colonize any planet where life evolves. fi, fc, and fL are irrelevant for calculating planets under GIM control. In fact, these numbers _do_ apply to Uplift. fl is 1, because the Progenitors fed the planets with life. fi is 2/[total number of species that ever existed] if you accept Earthclan's supersticions, or 1/[total] if you are an Awaiter. Otherwise, this question is anathema. (Alternatively fi=1, all planets with life get infested with intelligent life. fc=1, all inhabited planets participate in Galcatic Civilization. 0.12 fL .1 since inhabitable planets spend most of their existence in fallow.) Ok. Ngim = N* fp ne fl N* = 100*10^9 per SETI fp = 0.2 (conservative per SETI) ne = 1 (conservative per SETI) SETIst are optmistic fanatics :-) fl = 0.0001 (pretty conservative, but then the GIM is only interested in planets with *complex* life.) fl can be any number :-) That gives us 2M *naturally* existing planets in the Milky Way controled by the GIM and 10M naturally occuring planets under GIM control through five galaxies. If 4/5 of all GIM controlled planets are terrformed then we wind up with 50M GIM planets in five galaxies. Ok. But it's better to go back and set the Drake factors based on what we want to get in the end. Excellent idea! N* = 100*10^9 (that is, 1.00E+11) fp = .75 (most systems have planets) ne = .25 (few could support life, partly a cheat factor) fl = 3.00E-05 (3/100,000 have life, entirely a cheat factor. Implies there are a lot of terraforming candidates) fi = 1 (ALL good planets get colonized) fc = 1 (If colonized, the setlers participate in O-2 Civ.) fL = .125 (7 times out of 8 a planet is fallow) This gives the number of planets that could *naturally* support life in the Milky Way N = 7.03E+04 5 galaxies Total natural planets under GIM control = 2.81E+06 Total natural GIM leased planets = 5N = 3.52E+05 Natural/Terraformed = 1/6 Total GIM planets (B or C leasable) = 1.69E+07 (We don't count A class leases because they are in need of terraforming.) Total GIM B or C leases at present time = 2.11E+06 Giving us about 11.1 planets per race, which is close enough to 10. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: Habitable Planets: was Notes on Uplift
At 12:13 AM 1/9/04, Trent Shipley wrote: As a side note, Asimov's Galactic Empire includes 25M planets in a single Galaxy, all of them terraformed in the past 22,000 years. But Asimov was optimist about the existence of habitable planets, we know for sure that there can't be habitable planets around, for example, Epsilon Eridani, where Asimov placed Baleyworld-Comporellon. We do? -- Ronn! :) ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: Habitable Planets: was Notes on Uplift
Ronn!Blankenship wrote: But Asimov was optimist about the existence of habitable planets, we know for sure that there can't be habitable planets around, for example, Epsilon Eridani, where Asimov placed Baleyworld-Comporellon. We do? Doesn't Epsilon Eridani have a hot-Jupiter orbiting it in an elliptical orbit that crosses the region where liquid water is possible? Alberto Monteiro ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: Habitable Planets: was Notes on Uplift
At 06:37 AM 1/9/04, Alberto Monteiro wrote: Ronn!Blankenship wrote: But Asimov was optimist about the existence of habitable planets, we know for sure that there can't be habitable planets around, for example, Epsilon Eridani, where Asimov placed Baleyworld-Comporellon. We do? Doesn't Epsilon Eridani have a hot-Jupiter orbiting it in an elliptical orbit that crosses the region where liquid water is possible? It has a Jupiter-like planet. Not a hot Jupiter (a ~ 0.1 AU): the figure I seem to recall is a = 3.3 AU. I don't recall the eccentricity. Guess I'll have to look it up. 16 Cygni B, a well-known solar analogue (though possibly not as close as 18 Scorpii, which was described this week as a near-twin of the Sun) has a Jupiter-like planet whose orbit does cross from the equivalent of near the orbit of Venus to outside the orbit of Mars. -- Ronn! :) ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: Habitable Planets: was Notes on Uplift
Trent Shipley wrote: No. I propose that there are 2M planets _with_ galactic civilization settled on them. But they could be 20M or 200k. Good. So 2M is a _reasonable_ statistical expectiation for planets that could support civilzation across 5 galaxies. As a side note, Asimov's Galactic Empire includes 25M planets in a single Galaxy, all of them terraformed in the past 22,000 years. But Asimov was optimist about the existence of habitable planets, we know for sure that there can't be habitable planets around, for example, Epsilon Eridani, where Asimov placed Baleyworld-Comporellon. Stars come and go, planets come and go. The terraforming of planets should probably just keep the number of planets in a stable number. Lets come back to terraforming. I think that it would be a major (and s-l-o-w-l-y increasing) factor in the total number of habitable planets. The key word here is _slowly_. For practical purposes, we can suppose that the number is more or less constant during the lifecycle of a standard species [1 million years] BTW, I also guess that there are about 10 fallow planets for each settled planet, based on the data that a planet is usually leased for 100ky, and it is let fallow for a minimum of 500ky [usually more]. I am going to assume that a factor of 1:10 is the high end for an inhabited to fallow ratio if planets are leased for an average 100ky and fallow for a minimum of 500ky. What we need is a figure for mean fallow time. Lets pick 700ky. If there are 2M inhabited planets then there are 14M fallow planets. At any given time there must be a total of 16M habitable planets. Ok, 700ky, or 1My, don't change the final numbers very much Alberto Monteiro ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: Habitable Planets: was Notes on Uplift
On Thursday 2004-01-08 06:00, Alberto Monteiro wrote: Trent Shipley wrote: No. I propose that there are 2M planets _with_ galactic civilization settled on them. But they could be 20M or 200k. Good. So 2M is a _reasonable_ statistical expectiation for planets that could support civilzation across 5 galaxies. As a side note, Asimov's Galactic Empire includes 25M planets in a single Galaxy, all of them terraformed in the past 22,000 years. But Asimov was optimist about the existence of habitable planets, we know for sure that there can't be habitable planets around, for example, Epsilon Eridani, where Asimov placed Baleyworld-Comporellon. Stars come and go, planets come and go. The terraforming of planets should probably just keep the number of planets in a stable number. Lets come back to terraforming. I think that it would be a major (and s-l-o-w-l-y increasing) factor in the total number of habitable planets. The key word here is _slowly_. For practical purposes, we can suppose that the number is more or less constant during the lifecycle of a standard species [1 million years] BTW, I also guess that there are about 10 fallow planets for each settled planet, based on the data that a planet is usually leased for 100ky, and it is let fallow for a minimum of 500ky [usually more]. I am going to assume that a factor of 1:10 is the high end for an inhabited to fallow ratio if planets are leased for an average 100ky and fallow for a minimum of 500ky. What we need is a figure for mean fallow time. Lets pick 700ky. If there are 2M inhabited planets then there are 14M fallow planets. At any given time there must be a total of 16M habitable planets. Ok, 700ky, or 1My, don't change the final numbers very much Nope. Look. I want to write about Clan Tothtoon. To do that it would be helpful to pin down some numbers, namely: -Total number of races in O-2 Civilization now. (total number of individuals or biomass would be interesting but not critical) -Average number of clients per patron (obviously slightly more than 1) -- Distribution of access to clients among potential patrons (Members of Clan Tothtoon tend to be priviledged, the question is how priviledged.) -Total O-2 habitable planets now --- leased:fallow --- natural:terraformed --- proportion of A, B, C and homeworld leases. --- Mean number of planets per citizen race --- fairness in distributing leases. With regard to planets I visit: http://www.activemind.com/Mysterious/Topics/SETI/drake_equation.html N = N* fp ne fl fi fc fL N: communicating life. N*: number of stars, site suggests 100 * 10^9 for Milky Way alone fp: fraction of stars with planets ne: number of planets where life can exist fl: fraction where life evolves fi: fraction were intelligent life evolves fc: fraction that can and do communicate fL: fraction of timewhere communicating civilization exists Galactics will colonize any planet where life evolves. fi, fc, and fL are irrelevant for calculating planets under GIM control. (Alternatively fi=1, all planets with life get infested with intelligent life. fc=1, all inhabited planets participate in Galcatic Civilization. 0.12 fL .1 since inhabitable planets spend most of their existence in fallow.) Ngim = N* fp ne fl N* = 100*10^9 per SETI fp = 0.2 (conservative per SETI) ne = 1 (conservative per SETI) fl = 0.0001 (pretty conservative, but then the GIM is only interested in planets with *complex* life.) That gives us 2M *naturally* existing planets in the Milky Way controled by the GIM and 10M naturally occuring planets under GIM control through five galaxies. If 4/5 of all GIM controlled planets are terrformed then we wind up with 50M GIM planets in five galaxies. But for ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Habitable Planets: was Notes on Uplift
On Wednesday 2003-12-24 06:22, Alberto Monteiro wrote: Trent Shipley wrote: My estimate includes all five. Of course, as in Drake's equation, each factor has an error from 10% to 900% :-) * about 10 planets per race * about 200,000 races Alberto, as I recall Drake's Equation has no factor for Planets Fallow by order of the GIM. ??? What I said is that the factors I get for Uplift have error bars similar to Drake's equation's terms: they can be 1/10 to 10 times the guesstimate. Check. Are you proposing there 2M habitable planets, some of which are Fallow or that there are, perhaps, 6M habitable planets 2M of which are *not* Fallow? No. I propose that there are 2M planets _with_ galactic civilization settled on them. But they could be 20M or 200k. Good. So 2M is a _reasonable_ statistical expectiation for planets that could support civilzation across 5 galaxies. Have you made any allowance for an increase in the number of habitable planets due to terraforming? (Do you need to?) No, because I suppose that this is a small factor in the last, say, 500 My. Stars come and go, planets come and go. The terraforming of planets should probably just keep the number of planets in a stable number. Lets come back to terraforming. I think that it would be a major (and s-l-o-w-l-y increasing) factor in the total number of habitable planets. BTW, I also guess that there are about 10 fallow planets for each settled planet, based on the data that a planet is usually leased for 100ky, and it is let fallow for a minimum of 500ky [usually more]. I am going to assume that a factor of 1:10 is the high end for an inhabited to fallow ratio if planets are leased for an average 100ky and fallow for a minimum of 500ky. What we need is a figure for mean fallow time. Lets pick 700ky. If there are 2M inhabited planets then there are 14M fallow planets. At any given time there must be a total of 16M habitable planets. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: Habitable Planets: was Notes on Uplift
Perhaps of interest: Donald Savage Headquarters, WashingtonJanuary 7, 2004 (Phone: 202/358-1727) Steve Roy Marshall Space Flight Center, Huntsville, Ala. (Phone: 256/544-6535) Megan Watzke Chandra X-ray Observatory Center, Cambridge, Mass. (Phone: 617/496-7998) RELEASE: 04-013 CHANDRA LOCATES MOTHER LODE OF PLANETARY ORE IN COLLIDING GALAXIES NASA's Chandra X-ray Observatory has discovered rich deposits of neon, magnesium and silicon in a pair of colliding galaxies known as The Antennae. When the clouds containing these elements cool, an exceptionally high number of stars with planets should form. These results may foreshadow the fate of our Milky Way and its future collision with the Andromeda Galaxy. The amount of enrichment of elements in The Antennae is phenomenal, said Giuseppina Fabbiano of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass. at a press conference at a meeting of the American Astronomical Society in Atlanta. This must be due to a very high rate of supernova explosions in these colliding galaxies. Fabbiano is lead author of a paper on this discovery by a team of U.S. and U.K. scientists that will appear in an upcoming issue of The Astrophysical Journal Letters. When galaxies collide, direct hits between stars are extremely rare, but collisions between huge gas clouds in the galaxies can trigger a stellar baby boom. The most massive of these stars race through their evolution in a few million years and explode as supernovas. Heavy elements manufactured inside these stars are blown away by the explosions and enrich the surrounding gas for thousands of light-years. The amount of heavy elements supports earlier studies that indicate there was a very high rate of relatively recent supernovas, 30 times that of the Milky Way, according to collaborator Andreas Zezas of the CfA. The supernova violence also heats the gas to millions of degrees Celsius. This makes much of the matter in the clouds invisible to optical telescopes, but able to be observed by an X-ray telescope. Chandra data revealed for the first time regions of varying enrichment in the galaxies: in one cloud, magnesium and silicon are 16 and 24 times as abundant as in the sun. These are the kinds of elements that form the ultimate building blocks for habitable planets, said Andrew King of the University of Leicester, U.K., and a study coauthor. This process occurs in all galaxies, but it is greatly enhanced by the collision. Usually we only see the new elements in diluted form as they are mixed up with the rest of the interstellar gas. CfA coauthor Alessandro Baldi noted, This is spectacular confirmation of the idea that the basis of chemistry, of planets and ultimately of life is assembled inside stars and spread through galaxies by supernova explosions. As the enriched gas cools, a new generation of stars will form and, with the stars, new planets. Some studies indicate clouds enriched in heavy elements are more likely to form stars with planetary systems, so in the future an unusually high number of planets may form in The Antennae. If life arises on a significant fraction of these planets, then in the future The Antennae will be teeming with life, speculated Francois Schweizer, another coauthor, from the Carnegie Observatories in Pasadena, Calif. A vast number of sun-like stars and planetary systems will age in unison for billions of years. At a distance of about 60 million light-years, The Antennae system is the nearest example of a collision between two large galaxies. The collision, which began a couple hundred million years ago, has been so violent that gas and stars from the galaxies have been ejected into the two long arcs that give the system its name. The Chandra image shows spectacular loops of 3-million-degree gas spreading out south of The Antennae. These loops may be carrying out some of the elements dispersed by supernovas into intergalactic space, said Trevor Ponman of Birmingham University, U.K. The Antennae give a close-up view of the type of collisions that were common in the early universe and likely led to the formation of most stars existing today. They may also provide a glimpse of the future of our Milky Way Galaxy, which is on a collision course with the Andromeda Galaxy. At the present rate, a crash such as the one now occurring in The Antennae could happen in about 3 billion years. Tremendous gravitational forces will disrupt both galaxies and reform them, probably as a giant elliptical galaxy with hundreds of millions of young sun-like stars, and possibly planetary systems. Additional information and images are available at http://chandra.harvard.edu and http://chandra.nasa.gov -end- * * * NASA press releases and other information are available automatically by sending an Internet electronic mail message to [EMAIL PROTECTED] In the body of the message (not the subject line)
