jutntog1 Posted May 13, 2005 Posted May 13, 2005 im wondering (for a pro evoulution argument) how many planets are in teh universe (obvously a very rough estimate) do we have any idea do we have a minumum number?
Ewen Posted May 13, 2005 Posted May 13, 2005 You'd have to work with a vastly assumtious model of the universe based on current evidence. We have no idea in short.
C3H5(NO3)3 Posted May 13, 2005 Posted May 13, 2005 Hmm...well....for every grain of sand on the Earth, there are 100 000 000 (I think) stars...then....however many planets that has....yeah, we need more info.
GrandMasterK Posted May 13, 2005 Posted May 13, 2005 How many planets do we really have in our solar system, arent there like 2 more around the Neptune and Pluto area?
srh Posted May 13, 2005 Posted May 13, 2005 I think there is supposed to be two past pluto, but that depends on your definition of a planet. They're icey 'mini-planets'...in other words, huge arse (ass) ice-balls. I'm not sure if that's the technical defintion they've adopted though. Are they supposed to intersect with plutos orbit at any time?
Ewen Posted May 14, 2005 Posted May 14, 2005 The ones beyond Pluto are really just large asteroids. Pluto is really, but it's considered a planet by most people these days. There's a great line in the film / book 'Contact', that runs something like: "If just one in a million of [the galaxies in the universe] had a solar system, and if just one in a million of those had planets, and just one in a million of those had life, then there would be literally millions of other civilisations our there". The mathematics are missing but it's still a valid point to theorise from.
Vladimir Posted May 14, 2005 Posted May 14, 2005 I thought pluto had officially beem discounted as a planet?
luc Posted May 14, 2005 Posted May 14, 2005 im wondering (for a pro evoulution argument) how many planets are in teh universe (obvously a very rough estimate) do we have any idea do we have a minumum number? Two possibilities: an infinite number or a finite number. If it's a finite number I suspect that is a very HUGE number
Guest KennyJC Posted May 15, 2005 Posted May 15, 2005 Well, how many planets have we found evidence of so far? One or two hundred? And those are mostly just gas giants around the size or much bigger than jupiter... AND those are all within a couple of hundred light years. There will of course probably be many more smaller planets in the area of which we've already found the gas giants. Once we get some more advanced telescopes up and running me might be able to give a good estimate to how many planets there are in the galaxy if we can possibly see evidence of planets as small as earth and mars on nearby star systems.
Ewen Posted May 15, 2005 Posted May 15, 2005 I thought pluto had officially beem discounted as a planet? Some people don't consider it a planet but in many people's opinions, it is. It's a lot bigger than asteroids in its vicinity and that's the only thing that's helping it keep its status as a planet I think.
Halucigenia Posted May 15, 2005 Posted May 15, 2005 im wondering (for a pro evolution argument) how many planets are in teh universe (obvously a very rough estimate) do we have any idea do we have a minimum number? Question - how will this help in a pro evolution argument? Evolution is well proven on this planet why do you need any other planets? I guess you mean for an anti creationist argument to show that life did not only arise in one place in the universe. For that you would want proof of life on other planets and I am sorry to say that there is none. But in all likelyhood there must be life elsewhere.
insane_alien Posted July 16, 2005 Posted July 16, 2005 pluto is a bit dubious as it is borderline between planet and planetoid all the other "planets" as the media calls them are infact planetoids (really big chunks of stuff that have enough gravity to make them round andhave a half decent density)
Inferno Posted July 30, 2005 Posted July 30, 2005 ladies and gentlemen... i give you... the drake equaton (ok... so its more for intelligent life, but the principle is the same for finding how many planets are in the universe)(note: this is an estimate) The Drake Equation was developed by Frank Drake in 1961 as a way to focus on the factors which determine how many intelligent, communicating civilizations there are in our galaxy. The Drake Equation is: N = N* fp ne fl fi fc fL The equation can really be looked at as a number of questions: N* represents the number of stars in the Milky Way Galaxy Question: How many stars are in the Milky Way Galaxy? Answer: Current estimates are 100 billion. fp is the fraction of stars that have planets around them Question: What percentage of stars have planetary systems? Answer: Current estimates range from 20% to 50%. ne is the number of planets per star that are capable of sustaining life Question: For each star that does have a planetary system, how many planets are capable of sustaining life? Answer: Current estimates range from 1 to 5. fl is the fraction of planets in ne where life evolves Question: On what percentage of the planets that are capable of sustaining life does life actually evolve? Answer: Current estimates range from 100% (where life can evolve it will) down to close to 0%. fi is the fraction of fl where intelligent life evolves Question: On the planets where life does evolve, what percentage evolves intelligent life? Answer: Estimates range from 100% (intelligence is such a survival advantage that it will certainly evolve) down to near 0%. fc is the fraction of fi that communicate Question: What percentage of intelligent races have the means and the desire to communicate? Answer: 10% to 20% fL is fraction of the planet's life during which the communicating civilizations live Question: For each civilization that does communicate, for what fraction of the planet's life does the civilization survive? Answer: This is the toughest of the questions. If we take Earth as an example, the expected lifetime of our Sun and the Earth is roughly 10 billion years. So far we've been communicating with radio waves for less than 100 years. How long will our civilization survive? Will we destroy ourselves in a few years like some predict or will we overcome our problems and survive for millennia? If we were destroyed tomorrow the answer to this question would be 1/100,000,000th. If we survive for 10,000 years the answer will be 1/1,000,000th. When all of these variables are multiplied together when come up with: N, the number of communicating civilizations in the galaxy. Copyright http://www.seti.com
Inferno Posted July 30, 2005 Posted July 30, 2005 oh, it says 20-50% of 100 billion, s thats 20-50 billion extrasolar planets in the milky way galaxy alone.
DV8 2XL Posted July 30, 2005 Posted July 30, 2005 The number that is missing from the above estmate is the lifetime of the Milky Way Galaxy. When that is factored in the number of communicating civilizations in the galaxy at this moment drops to a million or so civilizations within our own galaxy with whom we might detect. However if we also limit ourselves to sub-luminal communication that number drops to about three.
Inferno Posted July 30, 2005 Posted July 30, 2005 Still, thats three civilizations that we dont know about. Sounds pretty exciting to me!
DV8 2XL Posted July 30, 2005 Posted July 30, 2005 Well I wasn't trying to throw a damper on things, just wanted to show that even running the Drake pessimisticly, we are not alone.
Inferno Posted July 30, 2005 Posted July 30, 2005 Well, thats a rough estimate for the Milky Way Galaxy alone. Considering there are billions of other galaxies out there, I'd say its pretty much guaranteed we are not alone. But, thats just my opinion...
Inferno Posted July 30, 2005 Posted July 30, 2005 A great book for this discussion is 'Probability 1'. Its all about mathematical proof of life, other than us, in our universe.
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