Thanks,all. I find these posts infinitely delightful, if not universally understood.
Cast one more vote for the “because something can be imagined, it does not mean it can exist” side of this discussion. We could get into the the whole “possible” vs. “probable” with this as well.
Patricinus Scriblerus writes, “First: IF the universe is infinite how can there be a finite amount of matter is one not dependent on the other??”
Well, it seems that no Real Astronomer™ has popped up to answer this, so I might as well take a swing at it. Disclaimer: I’m not an astronomer. I might be wrong here.
To your first question, I suppose that as long as one limit’s one’s self to talking about hypothetical universes, one can envision a universe with an infinite spacial extent but a finite amount of matter in it. But the more interesting question, IMHO, is your second one, where you ask, “And second How can any one prove the size of the universe?”
This is where I stand to be corrected by Real Astronomers™. But AFAIK, we there are two related questions: the univere’s age, and it’s size. We can estimate the universe’s age by noting that it’s expanding, and that this expansion obeys certain physical laws. We can extrapolate this backwards to t=0 and arrive at an estimate in the ballpark of 12 to 16 billion years old (which is even older than US Senator Strom Thurman!) So this puts a maximum upper bound on how big the universe could possibly be. The value of the Hubble Constant (the rate of expansion of the universe) is something scientists are trying to get a good handle on, because it affects the answers to all these other related questions.
To get an idea of how big the universe is, we need to be able to estimate distances to distant objects. For distances to nearby objects, we can use the earth’s orbit as a baseline and use simple trigonomotry to calculate the distance rather directly, but this method breaks down over longer distances since the earth’s orbit is so tiny. For more distant objects, other, less direct techniques are used. For example, we know about how bright certain classes of objects are by observing nearby ones, and if we see one of those objects in a distant galaxy, we can measure how bright it looks to us from here, and thus estimate how far away it is. Think of it like this: if you see an automobile headlight pointed right at you from 10 feet away, it looks very bright indeed. But that same auto headlight pointed at you from 2 miles away won’t appear very bright at all. If you know it’s pointed right at you in both cases, you can estimate its distance based on how bright it looks. (There are limitations and problems with this technique of course, such as interstellar dust absorption). Another technique is to observe that for a given class of galaxy, the distance between its stars similar to other galaxies of the same class. So by looking at how “grainy” a galaxy looks to us from earth, we can estimate the angular separation of it’s stars, and because we know the actual separation of the stars in that type of galaxy, we can estimate the distance to the galaxy. There are many other techniques, all with various limitations and sources of error, but combined, they give us at least a rough picture of how far away things are.
So (consider this subject to correction by anyone who knows more about this than I do): AFAIK, the process goes like this. We estimate the distances to some not-too-distant galaxies at various distances from us as accurately as we can. We can measure their rate of recession quite accurately by looking at the redshift of their spectra. Doing this allows us to estimate the Hubble constant. Knowing the hubble constant, we can estimate how old the universe is, and when we know that, we can estimate how far away the very oldest objects are.
Ok, so there’s a fair amount of handwaving in there, but until you get a better answer from a Real Astronomer™, maybe this will suffice 
k0myers
k0myers brings up an interesting idea, if we map out the most distant objects in each segment of the sky, they should describe the edges of the known universe, and should tell us the geometry. Has anyone ever bothered to do this?
Falcon2,
As far as I understand it (and again, I’m not an astronomer, so take this for what it’s worth!), is that the universe is basically closed. It doesn’t have an “edge” per se.
The usual example used is a balloon, the surface of which is a 2D surface, but there’s no “edge” to this surface because it’s curved throughout one higher dimension. As far as I understand it, our universe is thought to be the same way, just one higher dimension up. We can’t see all the way around it; as we look farther back in time (and thus farther away in distance), our ability to see things becomes progressively more limited since the universe was denser/hotter/etc back then.
But I don’t understand the intricacies of the theory here, so I’m probably not the best one to answer this question. Maybe there’s somebody with a real astronomy background lurking?
k0myers
Oh, the other thing I forgot to add is that there i a lot of research going on into large scale (100+ LY) structures in the universe. I don’t pretend to understand the significance of this, but large groups of galaxies are grouped into larger structures, sometimes hundreds of lightyears across. I think they’re measuring the location of as many galaxies as possible to get the best map they can. Measuring the angular position of a galaxy is trivial, but measuring its distance is difficult, so there’s only so much they can do.
k0myers
To back up k0myers’s remarks of 07-05-99 11:10 PM, let me point out that Nobelist Ilya Prigogine demonstrated some 20-odd years ago that systems that are sufficiently far from equilibrium can exhibit local “reversals” of entropy, or what he called “order through fluctuations”.
Prigogine’s findings repudiate the view that entropy and the laws of thermodynamics make the “spontaneous” (i.e., non-Created) development of life impossible.
On another point, I think there is some confusion about the idea of an “infinite” universe. As others have already pointed out, the universe is not infinite in terms of space; astronomers and cosmologists call the universe “finite, but unbounded”. But it would certainly appear to be infinite in terms of future time.
As for Wayne McDougall, I agree with your conclusion but not with the way you reached it. The existence of something in someone’s imagination has no bearing on its existence in reality.
SoulFrost: I second your succinct answer to falcon2’s Quantum Berkeleyism.
Finally, AuraSeer’s post intrigues me (in line with SBW’s remarks). I agree with everything up to the last sentence of Aura’s last paragraph:
“Possibility” probably shouldn’t be confused with “probability” – I don’t think that’s the way either one of them works. In order to estimate the probability of an event, doesn’t the occurrence of the class of event in question have to be in some sense known and predictable? For example, even though the time at which a particular atom will decay is unpredictable, the probability of this kind of event is based on quantum theory (and perhaps measuring large numbers of decay events and plotting a distribution); i.e., it’s based on the fact that decay is known to exist.
Saying that something is possible doesn’t say anything more than that its existence wouldn’t violate known natural laws – it doesn’t say anything about the probability of that state occurring, nor does it say anything about the frequency with which the event might occur. In other words, I can’t imagine why there could not be “possible” events whose probability is zero. I’m not convinced that “possible” and “probability > 0” are synonymous…
… but it’s a damn interesting, if highly confusing, question for debate!
I have a question and I would also like to include, in my opinion, the correct answer. First, I would like to start with how I arrived at this question. So, if life is all made up of energy and e=mc^2. Which means mass can be changed into energy, and energy can be changed into mass. While keeping in mind that we are carbon, which comes from the explosion of stars. Then this must conclude that the universe, being only one essence, energy, is eternal. Since we are made up of this energy then does life ever die beyond our human identity? Also, because I believe that life continues forever, there must be life on other planets. This brings me to my main question, since there must be life on other planets then is it human life? Or is life spontaneous with energy creating everything that will can exist will exist? I believe that everything that could possibly exist will exist and I came to this conclusion that the human form is perhaps, not all that common. I am basing this reasoning off the fact that looking back on the Earth timeline, dinosaurs were the dominant species on the entire planet. Why did dinosaurs not reappear after they were wiped out by the asteroid that struck the Yucatán Peninsula 65 million years ago? Perhaps, the conditions of Earth were different and evolution can take whichever path it needs to, in order to adapt to survive. So, my last question would be are there different, random life forms on other planets that are in the habitable zone, capable of maintaining life?
There are actually laws of conservation that put limits on this. A proton cannot be changed into radiant energy, unless an anti-proton is also annihilated.
This doesn’t follow. All of the matter/energy in the universe may have come from a specific origin, and it might all go away some day in some kind of end.
As far as we can tell, yes, life dies. Those of us who have grieved over the loss of relatives may take religious comfort in the faith-based belief that the personality continues, but there is no evidence for this, and so the most honest possible answer is that life does not continue after death.
This doesn’t follow either. It could be possible that Earth is the only place with life. The current thinking is that this is probably not true, given the discovery of earth-like planets, but it is possible that we’re the one in a trillion fluke of nature.
Given that human life is the result of trillions of trillions of little evolutionary incidents, none of which are repeatable, the odds are WAY against it. Alien life will probably be “alien.” There might be resemblances – aliens might have eyes. But there’s no reason to assume they have five fingers, two eyes, an uvula, and hair up their nostrils.
Nobody knows, at this point. We may some day develop spectranalysis that can resolve the presence of molecules such as chlorophyll or DNA (ha! as if!) in distant planets, but that’s one hell of a long shot. We’ll probably have to go out and look.
That is not dead which can eternal lie.
And with strange aeons, even death may die.
– H. P. Lovecraft
Kind of like this thread.
…like Zombies? Or Zombie THreads?
As has been pointed out ages ago, even if something were infinite, it doesn’t mean that all possibilities will occur.
William R. Bennett wrote an article “How Artificial is Intelligence?” that appeared in the October 1977 issue of American Scientist, in which he performed the “Monkeys with typewriters” experiment to see how it worked out. Instead of monkeys, he used a random number generator, and instead of typewriters, he used his computer. He let the random number generator loose on a set of alphabetical keys, plus spaces. He got gibberish back.
He then fixed it so that the individual letters (and spaces) showed up with the same frequency as in English. Things looked more like words, but it was still gibberish.
So instead of looking at the probabilities of individual letters, he programmed in the probabilities of pairs of letters. So his random number generator worked on not only single letters, but what came next. He called these “second order monkeys”. The results looked much more like English.
https://en.wikipedia.org/wiki/William_R._Bennett,_Jr.
Well, you can see where to go from there. He generated third-order monkeys, and fourth-order monkeys, and higher orders. He tried different texts to obtain his probabilities. He tried it with languages besides English.
The results were interesting.
1.) 3rd and 4th order monkeys produced a lot of actual words, including a surprising number of obscenities. (“longue asse kisses” showed up in one screed of text)
2.) By the time you get to 5th or 6th order monkeys in a language you’re not familiar with, it’s hard to tell monkey-text from real examples of that language.
3.) With fifth or higher order monkeys, you can often tell something about the nature of the text from which you derived the statistics. You can distinguish Shakespearean monkeys from Time magazine monkeys
4.) Ultimately, though, Bennett said that it was extremely unlikely that he would ever recover the texts he used for his probabilities from the random typings of his computer “monkeys”. There simply wasn’t enough “noise” in his pseudo-random number generators. Not to mention how long it would take. It’s possible that , in an infinite universe, you’d get the text back, but it’s not guaranteed (although I could see a lot of texts with only a few typos. The Library of Babel ought to have used book sales where you can purchase such almost-0right editions.)
Life isn’t eternal. Zombies might be.
I think all possibilities will occur.
Remember, there are only a finite number of ways matter can be configured. Also, there are more likely and less likely arrangements (e.g. H2O is a likely arrangement).
So, take a big pile of atoms and arrange them one way. Then arrange them another way and so on.
There will be a LOT of ways you can arrange those atoms but in the end it is a finite number.
If you do that infinite times you will not only get every combination you will get repeats.
Consider there is the Poincare Recurrence Time of the universe. This postulates how long it will take a finite universe to run through all arrangements of matter and, basically, go back to a given configuration. So, on a long enough timeline, you will exist again.
Of course that time is a really, really, REALLY long time. Something like 10^10^10^10^2.08 for our universe.
If that is the case for really long time scales in a finite universe I see no reason it wouldn’t be the case in an infinite universe (there would be infinite numbers of you in that universe).
This still doesn’t guarantee that all possible rearrangements will exist. From your cite:
(emphasis mine)
It could be phrasing.
This is an easy concept to get.
Imagine I give you three rocks. How many arrangements of those rocks can you make before you repeat an arrangement? (a: 6) Four rocks? (a: 24) Five rocks? (a: 120)
And so on. The number start getting ridiculously big really fast but we can see there is still a finite number of arrangements. Eventually you have to get repeats.
Perhaps you are suggesting that it is possible to roll a six sided die an infinite number of times without the “6” ever coming up. I guess that is theoretically possible but staggeringly unlikely (as in forever getting closer to zero without ever quite getting to zero probability).
If you are a betting man the smart bet would be that eventually you will see that six.
Once, very long ago, I read an article somewhere (was it “Omni”?) where someone was (I think seriously) proposing extending the monkey theme into a random pixel generator run by a computer. Given enough time, he felt that it would not only generate any and every text in any and every language (Shakespeare’s First Folio, for example), but it would also generate blueprints, designs, and circuit diagrams galore. The he would set a second computer to look for sense in the output of the first, sifting out the obvious chaff. He argued that the system would include plans for inventions not yet invented (such as anti-gravity boots, transporters, ESP helmets, and the like).
Even as a callow youth, the idea struck me as ludicrous.
I just want to mention that this is the oldest zombie I have ever clicked on. For a minute there I thought my browser was broken.
It’s not ludicrous in the sense it is impossible. In theory you could do that.
The ludicrous part is in how long you’d have to wait for anything useful to come out of it.
How could you tell the good from the bad?
Maybe the design is near perfect, but “the polarities are crossed”, and when you build it, you blow up the world! (Or it works perfectly, making wonderful farting noises.)