tim@ism780c.UUCP (03/25/87)
Note: I have redirected followups to sci.misc, since this has little to do directly with misc.kids anymore. A fun thing to do is to pick some population limit, and see how long it would take to reach it. Let's assume a 1% annual growth rate. The last time I checked ( which was quite a while ago, the growth rate was higher than this. I have no idea what it is now. ) Let's start with a fairly low limit: the entire surface of Earth, including the oceans, packed with people to a density of one person per square foot. This would take about 1400 years. Let's go a bit farther. The entir volume of the Earth replaced with people. This would take less than 2800 years. Let's get really silly now. How long until we have so many people that the amount of space occupied by people is expanding at the speed of light? About 11,000 years. Does anyone want to argue that this is not an upper bound on human population? Another interesting one to calculate is how long it would take to fill the galaxy, assuming each star has a few planets that we can make into habitable places. It is on the order of 4000 years. Note that without faster than light travel, this won't work. It seems pretty clear that we can't maintain a 1% population growth rate forever. It will have to be slowed down. The only question is how. The death rate can be increased, or the birth rate can be decreased, or both. Any comments? Anyone see any holes in this analysis? -- Tim Smith Welcome to Wackyland uucp: sdcrdcf!ism780!tim "It can happen here" Compuserve: 72257,3706 Pop: 100 nuts and a squirrel Delphi or GEnie: mnementh
lambert@mcvax.UUCP (03/26/87)
In article <5818@ism780c.UUCP> tim@ism780c.UUCP (Tim Smith) writes: > Note: I have redirected followups to sci.misc, since this has little > to do directly with misc.kids anymore. Aren't there any sci.kids? > A fun thing to do is to pick some population limit, and see how long > it would take to reach it. Let's assume a 1% annual growth rate. > [...] > Let's get really silly now. How long until we have so many people > that the amount of space occupied by people is expanding at the > speed of light? About 11,000 years. Does anyone want to argue > that this is not an upper bound on human population? Yes, since you could slow down reproduction (which would happen near the speed of light anyway) and still expand. Another matter is that with unchecked reproduction at a constant 1% rate the pop count would exceed the estimated number of elementary particles in the universe in about 18,300 years. That seems a pretty safe upper bound to me, but then they might discover new hierarchies of sub-elementary gizmons in the next 183 centuries. -- Lambert Meertens, CWI, Amsterdam; lambert@cwi.nl
tim@ism780c.UUCP (03/27/87)
In an article, lambert@boring.UUCP (Lambert Meertens) writes: >In article <5818@ism780c.UUCP> tim@ism780c.UUCP (Tim Smith) writes: >> speed of light? About 11,000 years. Does anyone want to argue >> that this is not an upper bound on human population? > >Yes, since you could slow down reproduction (which would happen near the >speed of light anyway) and still expand. Oops. I meant to say "Does anyone want to argue that we can keep up a one percent growth rate longer than 11,000 years?" On misc.kids, this started as a discussion about why people wanted large families. It soon turned into an argument between those who advocate population control now, and those who think that more efficient use of farmland, and perhaps expansion into space, will allow us to maintain the current population growth rate indefinitely. -- Tim Smith Welcome to Wackyland uucp: sdcrdcf!ism780!tim "It can happen here" Compuserve: 72257,3706 Pop: 100 nuts and a squirrel Delphi or GEnie: mnementh
janw@inmet.UUCP (03/28/87)
[tim@ism780c.UUCP ] >Let's get really silly now. How long until we have so many people >that the amount of space occupied by people is expanding at the >speed of light? About 11,000 years. Does anyone want to argue >that this is not an upper bound on human population? I do. The physical universe as we know it is not the same as the physical universe our ancestors knew - even 100 years ago, still more different from 1000 years ago, still more 11,000 years. It is arguable that the change accelerates. Therefore, considerations based even on the most fundamental principles of modern science cannot be projected too far where the evolution of the species that discovered them is concerned. E.g., consider the science-fiction idea of parallel universes. There is, of course, no reason to predict our heirs will discover such things and expand into them. Or that they won't. They'll know far better - we can't predict a damn thing about them, as our paleolithic ancestors couldn't about us. Any particular long-term prediction made now is unlikely to come true. And this applies to the prediction that the limit indicat- ed in the top paragraph will stay valid. Except in one sense: >upper bound on human population? ^^^^^ Our descendants 11,000 hence are unlikely to be human. Artificial evolution is already beginning to be technically possible. Jan Wasilewsky