

Subject:
Universe  finite or infinite?
Category: Science > Astronomy Asked by: andytheindoeuropeanga List Price: $20.00 
Posted:
19 Jan 2005 15:54 PST
Expires: 18 Feb 2005 15:54 PST Question ID: 460093 
Have astronomers, astrophysicists, cosmologists, and general physicists decided definitely whether the universe is infinite or finite? Also, what I don't understand about the Big Bang theory is if the universe was once a microscopic point, doesn't that imply that there was an "outside" beyond the bounds of the microscopic universe? Would this "outside" be not of the universe, or would it just be the empty part of the universe, or another universe, or does no "outside" even exist? How can the universe have a size if there is no such thing as "outside" or "beyond" the (limits of) the universe? Does the universe have size? Is the "universe" as implied by the Big Bang theory merely phenomena within the universe, such as stars and nebulae, i.e. matter and energy  and the limit to the universe is the limit of occurrence of these phenomena? But what about beyond these phenomena? Wouldn't there just be empty space extending to infinity? I actually find an infinite universe much easier to grasp intellectually than a finite universe, since a finite universe to me always implies something "outside" the universe which defines the boundary of the universe. 

Subject:
Re: Universe  finite or infinite?
Answered By: hedgiega on 03 Feb 2005 23:14 PST Rated: 
The succint answer, such as may be subject of wager offered in the comment From: silver777ga on 19 Jan 2005 23:58 PST " I will even bet you your 20 bucks .." succint answer is NO. At this time of an universal evolution, cosmologists are deeply engaged in educated guesses, arguments, complex calculations, construction of models and invention and revision of theories and speculations. The cosmologists are definitely undecided and there is no concensus. It is even worse with general public, which has same atitude to this question, as adolescents have to sex: they do not understand it  but it fascinates them. Result are myths and jokes, which do not seem funny any more, once you get actually involved in the study of the subject. An example: People speak of the 'dark matter'  but fact is that noone ever saw it. Only reason it was invented was to save some theories which are otherwise falsified by recent experiments. We all understand that baloon, goldtooththrillerga and others' keep talking about, is boundless but finite  but that baloon is also curved. To imagine a surface which is everywhere flat, and closed upon itself is very dificult, in any number of dimensions. I dare to say that a region of a flat space (E.n) is either bounded or infinite (Is that not a theorem, Mathtalk?) Time before the Big Bang is discussed e.g. by physicist Paul Davies, I believe it is in his book "Arrow of time" http://www.usyd.edu.au/time/price/preprints/arrow.html in the following context: Imagine the 'elliptic' (rather then parabolic or hyperpbolic) case of a universe (for definition see SEARCH TERM: elliptic universe ) which is the case in which universe will eventually start shrinking, reaching a Big Crunch ... and then what? We can imagine matter will get very dense, very hot, atoms broken to smitereens, particles bouncing apart, and new expansion starting ... Ancient greeks had a concept of such cycle called 'A Great Year'. Davies is asking: are such (possible) cycles a 'steady state'  same each time  or are the oscillations damped? If so, is universe evolving to some future equilibrium  sort of neothermaldeath? That much for fashionable myths. We just do not know. Even hundred years from now, it is unlikely that this question will be closed. Universe is very big, and we only know the tiny bit. All current cosmological models assume the SEARCH TERM : fundamental cosmological hypothesis according to which the universe is homogeneous (same everywhere  on the scale of galaxies) and that hypothesis is likely to be soon falsified experimentally. So, we do not know the answer. Right now, in the year of physics, 100 years after Einstein's discovery of spacetime, we are beginning to realize how little we know. We do know that we need to think about universe as a 'spacetime'  in the framework of General Relativity Theory ot GTR. In most cases relativistic geometry M4 can be reduced to ordinary Euklidian geometry and time (M4 > E3+ E1) . If we do that with current mainstream SEARCH TERM : Big Bang model, we get the model you mention: Mostly empty, infinite space E3, in which matter is flying apart, more and more slowly. It may stop and start falling back (elliptic case), keep slowing down to zero, (parabolic case) or, if it has enough kinetic energy to overcome the gravity (hyperbolic case) it may keep expanding. We do not even know which case we have  as sky surveys come too close to parabolic  to zero energy case  to decide. Then Davies's speculation opens the door to hybrid cases, where ratio of kinetic and gravitational energy is changing, and hyperbolic universe can become elliptic, with time. However, when it comes to universe, all nonrelativistic aproximations are very poor, as we cannot ignore the fact that speed of light is finite: Light of the distant stars take a long time to reach us. Father they are, the longer it takes. It is clear that there ARE REGIONS OF SPACETIME from which the light cannot reach us. We are not even saying 'never reach us' because that is the E3+E1 (classical) thinking. To think about these issues, we would have to be able to imagine the universe as a curved M4 surface, possibly imbedded in higher dimensional E.n (with n>4) where the light does not propagates. The light rays are all already on the models (are geodetics of that surface) and we just study which regions are connected (and so interact) and which are not. There are regions of that M4 surface, which we do not see  meaning there are no geodetics (light rays) leading from thereandthen to hereandnow. Regions which do not influence us in any way. There are events which are beyond OUR Event Horizont. Are these part of our universe? We may construct models, using the current cosmological hypothesis. Subject to Occam principle, as our knowledge of our corner of universe is expanding, we may introduce more complex models. But we have no way of knowing directly how this complex curved surface would look if we could see it. It is possible that this question will never be decided. As long as the mankind is exploring the universe, our knowledge will grow and our model will grow more complex. It is also possible, even likely, the way some superpowers are acting out lately, that civilisations reach certain level of technology and then destroy themselves. That would not end the universe, but it would definitely close this question. That possible outcome would explain why we did not get any ET visits as yet. If you are really interested in exploring the meaning of some of these M4 terms, the curved surfaces imbedded in higher dimensional spaces, you can look at the visulisations of GTR and of STR which have been posted on the internet. Start with SEARCH TERM: light cone Hedgie 
andytheindoeuropeanga
rated this answer:
Although I appreciate your honesty in providing a general answer to my question, I found that your grammar and punctuation and even occasionally spelling were atrocious  pardon me if you are a foreigner. Plus I didn't like your frequent interjections of "SEARCH TERM". But more importantly, you did not seem to address the second part of my question, as to whether a finite universe implies that there is something outside the universe which defines its limits, or whether there is nothing (and what exactly would "nothing" be  same as empty space, or something else?). But you did convey effectively the reality of the disaccord among scientists about the answer to my basic question. So for that part I am satisfied. Nevertheless I feel your answer could have been better, at least grammatically correct! 

Subject:
Re: Universe  finite or infinite?
From: goldtooththrillerga on 19 Jan 2005 20:11 PST 
It has been theoretically determined that, from the amount of dark matter and dark energy in the universe, the universe is indeed flat in shape and finite in area. Although the size of the universe is finite, it is boundless. To demonstrate this, the balloon analogy is most often used, where the universe would be the surface of the balloon. As the balloon inflates, the area increases, but stays finite. Also, the balloon has no edge, and there is no "center of expansion" therefore the balloon is boundless. The only thing differing in this analogy is that the universe is a threedimensional boundless surface, rather than the twodimensional surface of the balloon. The Universe's size as far as we can tell is at least 14.3 billion lightyears across, because that is the last scattering surface of light from the big bang, and which is, with presentday instruments, impossible to see past that distance. To talk about a time or space before the Big Bang from the perspective of our Universe is folly, because there was no space and time as we know it, and yet it seems to be a paradox to us because naturally something has to come from somewhere. There are present theories today that describe our Universe as one in an infinite array of universes known as the multiverse or the manifold of universes. These theories also describe how a universe such as ours could have "budded off" another universe by the way of a singularity. 
Subject:
Re: Universe  finite or infinite?
From: tlspiegelga on 19 Jan 2005 20:39 PST 
Perhaps this will be helpful to you: The Universe: Finite or Infinite? Copyright © 2002 by Ronald Pisaturo. All rights reserved. http://pages.prodigy.net/rpisaturo/Universe.htm ========= The Universe: Still Boggling the Minds of 'Finite Creatures' By Robert Roy Britt http://www.space.com/scienceastronomy/astronomy/universe_overview_0106051.html http://www.space.com/scienceastronomy/astronomy/universe_overview_0106052.html 
Subject:
Re: Universe  finite or infinite?
From: cynthiaga on 19 Jan 2005 20:45 PST 
Hi andytheindoeuropean, I think String Theory might interest you. I urge you to watch this NOVA special. It's phenomenal. WATCH THE 3 HOUR SPECIAL (FREE): The Elegant Universe MAIN PAGE: http://www.pbs.org/wgbh/nova/elegant/ DOWNLOAD PAGE: http://www.pbs.org/wgbh/nova/elegant/program.html Each of the 3 hours are broken up into 8 minute sections. The Official String Theory Web Site MAIN PAGE: http://superstringtheory.com/ Cosmology  How Old Is The Universe? http://superstringtheory.com/cosmo/index.html Wikipedia  String Theory http://en.wikipedia.org/wiki/String_theory ~~Cynthia 
Subject:
Re: Universe  finite or infinite?
From: mathtalkga on 19 Jan 2005 21:17 PST 
The finite vs. infinite question is very interesting. It is thought that the universe has only finitely many dimensions, although it is quite conceivable that the number of dimensions is eleven rather than four. Speaking of the fourth dimension, there's a good bit of concensus that the universe has "existed" for a finite length of time up to "now", as goldtooththrillerga notes. But the abundance of dark energy theoretically causes an accelerating expansion of the universe. The universe will thus "exist" for an infinitely long time, or else after 10^30 years the universe will grow so dull that at the least it will seem to be taking infinitely long for time to pass. regards, mathtalkga 
Subject:
Re: Universe  finite or infinite?
From: silver777ga on 19 Jan 2005 23:58 PST 
Andy, Fantastic question. Some things, we are not meant to know I'm sure. Have you considered infinite finiteness? Is infinity a paradox? Like the Moebious (sp) strip with an unending single surface, might our understanding of infinity in fact be finite? Theories of singularity and complimentary universes help us to attempt understanding. As does string theory. Turning your thoughts 180 degrees, what of infinity toward the interior? A cell, a proton, a string .. fractions within a line .. yet a point is a dividable line .. infinitely .. where does it end? Maybe it never ends, but as we exist as humans, we seek closure to all events. But then what lays beyond that closure? Logic suggests that it is never ending, and raises further questions. We are intelligent enough to ask the questions. Are we intelligent enough to accept the answers if and when they arrive? Or, do we blindly accept what is, to be just that without question? A minor example: http://chuck.charleshart.net/Mathomagic.php If you can find the ultimate answer for 20 bucks, it's a cheap investment for you and all who read your words in question. I will even bet you your 20 bucks that there will be no succinct answer to your question beyond theories. Phil 
Subject:
Re: Universe  finite or infinite?
From: frdega on 20 Jan 2005 04:06 PST 
I have always found the concept of infinity difficult to grasp Especially when applied to the Universe With an infinite Universe the chances on a little green man having set off on a 1000 light year journey  and landing on my keyboard ... now ... are 1. Of course it could be a finite Universe in an infinite void  but that 'begs the question'  in the true sense of the phrase 
Subject:
Re: Universe  finite or infinite?
From: guzziga on 20 Jan 2005 15:50 PST 
Infinity is easy  programming a video is what?s difficult. Best 
Subject:
Re: Universe  finite or infinite?
From: pinkfreudga on 20 Jan 2005 16:02 PST 
I like the "turtles all the way down" theory. 
Subject:
Re: Universe  finite or infinite?
From: silver777ga on 20 Jan 2005 17:23 PST 
" .. turtles all the way down .. " was debunked after much deliberation, Pink. It turned out to be an error in dictation by a hard of hearing note taker. Reference was to planetary orbits. " .. hurtles all the way around .. " were the intended words. Phil 
Subject:
Re: Universe  finite or infinite?
From: pinkfreudga on 20 Jan 2005 17:28 PST 
Oh, dear. I have based my entire view of cosmology on a typo. Next you'll be telling me that Planck's constant was really not a constant at all, but a contest, and it's too late for my photons to enter it. 
Subject:
Re: Universe  finite or infinite?
From: silver777ga on 20 Jan 2005 22:47 PST 
Andy and Pink, Andy .. I hope you will forgive our side notes. I also trust that you enjoy a touch of humour. Pink .. If Poker was wordplay, you'd win every hand. (Were the turtles female Russian ones by chance?) Phil 
Subject:
Re: Universe  finite or infinite?
From: hedgiega on 04 Feb 2005 21:38 PST 
Re: Is there something outside the universe Andy, By definition, there is nothing 'outside' the universe. When we say 'finite' we mean boundless but finite like that balloon  or surface of the Earth. You could have asked for clarification, if these terms were not clear. I do apologize about my spelling. English is indeed not my first language, but I should run the answer through the spelling checker. Usually I do, but I focused on the content too much, this time. Sorry about that. Thanks for the rating. 
Subject:
Re: Universe  finite or infinite?
From: silver777ga on 04 Feb 2005 21:55 PST 
Ummm .. Is there anything I can do here? If I make a bet and a promise, I keep both. I'm happy to split my ante on future meaningful questions for you Andy. That is, I am willing to spend $10 of my own money if you two will come to some agreement that will benefit the both of you and perhaps the greater community of us so fortunate to have access to a computer. I respect your command of the English language Andy, however Hedgie was simply providing you with search terms for your own use and for the purpose of clarification in arriving at the information provided to you. Researchers may become tired after toiling away for hours. Provided that the information is forthcoming to answer your question, and IS decipherable, you have achieved an answer to your inquiry. I had no trouble in following Hedgie's informative answer to your generalised question. In fact, I learnt from it. It's your call guys. Phil 
Subject:
Re: Universe  finite or infinite?
From: andytheindoeuropeanga on 05 Feb 2005 13:56 PST 
OK, I received criticism from Phil (silver777ga) that my own criticism was too harsh. Sorry, Hedgie, perhaps I had a bad day. I realize that you're not exactly writing for a scientific journal, and now I know (as I suspected) that English is not your first language. I will take advantage of the links (search terms)you and others have provided, as well as the suggested books, to further research my question. I still would like to know, though, that if a boundless finite universe has nothing outside it, how can it be boundless? Doesn't that mean it ends  and if something ends, doesn't another thing begin? And is that other thing, the "nothing" that is at the limits of the universe, not empty space? Or is empty space not nothing, and "nothing" cannot be conceived mentally? Or is the idea of true "nothing" and boundlessness a concept one is not meant to be able to visualize, they're just words we must accept in describing the universe? Well, you don't have to answer once again, you've already provided your answer. Thanks. I think perhaps I should have at least given you three stars, since you did provide a lengthy answer and plenty of crossreferences. Thanks again, Andy the IndoEuropean 
Subject:
Re: Universe  finite or infinite?
From: silver777ga on 05 Feb 2005 18:55 PST 
Andy, You're a gentleman. Well said. Phil 
Subject:
Re: Universe  finite or infinite?
From: hedgiega on 06 Feb 2005 20:28 PST 
Greetings from your fellowindoeuropean, Andy, I accept the apology, but based on the average rating of 4.6 rating of my other physics answers, I would still feel you did not 'got', what I wrote, about the finiteness of the universe, if you would give me three stars. Problems with physics questions on GA is usually not the correct science; that's the easy part. The challenge is to gear the answer to the interest and background of the asker, often on too meager information we get on his or her prior knowledge. The problem with this question is that too much was written about it, philosophy, math, physics,.. and it is very easy to get lost in it. What people can get from GA, what you would be able to get, if you would not end the dialog in such a haste, and can still get posting another, more specific question, is customized guide to literature. Literature is enormous and covers all those aspects on different levels (here is a small sample: http://www.reciprocalsystem.com/nlst/references.html ) There are different views, but some common base of knowledge and concepts: what is space, what is empty, curved and higher dimensional space and various geometries, have been established and are understandable, if approached well. If you want to get how, ".. finite universe that has nothing outside it, how can it be boundless? " then you need to pay more attention to these E3, M4, En, symbols, which people use to describe different geometries and spaces of different dimensions. At one time people where wondering if they can fall 'of the end of the Eart as bible is referring to ".. [one] end of the earth even unto the [other] end of the earth ..". Some people still believe in the Flat Earth and some in a flat universe. On the surface of Earth there is no boundary  it is a sphere. You keep going North, and come back from the South. There is no end and it is finite. There is no wall, no end. It is similar with universe. There is a serious project underway, which is matching what we see looking in two opposite directions of the sky, but this is just one of many possible ways it can be, and how it can be understood and verified. To conclude: I would recommend this one book: http://www.amazon.com/exec/obidos/searchhandleform/ref=s_sf_b_as/10428475085235145 As an intro to the filed. It provides readable overview of evolution of the current philosophical concepts of space. It is nonmathematical, but well informed about modern physics. Have a happy journey into the mysteries of space and time Hedgie 
Subject:
Re: Universe  finite or infinite?
From: hedgiega on 06 Feb 2005 20:31 PST 
Correcting a typo: As an intro to the filed. should be as an intro into this field. (I dit run it through a checker this time, but then I do some last minute editing  and mess it up again. So, sorry about a typo.) 
Subject:
Re: Universe  finite or infinite?
From: hedgiega on 06 Feb 2005 20:42 PST 
Ouch  That book link is messed up too. I will try again: Recommended book is: Boston Studies in the Philosophy of Science: The Concepts of Space and Time  Their Structure and Their Development (Synthese Library : No 74) by M. Capek (Paperback  December 1, 1975) Publisher: Kluwer Academic Pub (December 1, 1975) ISBN: 9027703752 and amazon reference is http://www.amazon.com/exec/obidos/tg/detail//9027703752/10428475085235145 it looks like it got some 'rare and expensive' status now, but should be available in most college libraries. Also available in hard cover: http://www.amazon.com/exec/obidos/tg/detail//9027703558/qid=110775116/10428475085235145 
Subject:
Re: Universe  finite or infinite?
From: andytheindoeuropeanga on 07 Feb 2005 11:01 PST 
Thanks once more for your further comment, "Hedgie". I did say "at least" three stars, so if spelling and grammar are overlooked I might have given you four stars. But the reason why I hesitate to commit myself to four stars is that you, like other physicists, have invoked the idea of a sphere, like the Earth or like an inflated balloon, to describe the idea of "finite but boundless". I have always found this to be an unsatisfactory analog because to me at least the sphere does have a boundary: it is the surface of the sphere. For once you go up or out from the surface of the sphere, you no longer encounter that surface, but rather encounter air. So it is with the Earth: the boundary of the Earth is the surface of the Earth, the Earth's crust  it ends where air (or, if you prefer to include the atmosphere as part of Earth, space) begins. Thus the Earth is finite and it does have a boundary  its surface. "Outside" the surface of the earth is air (or space if you include the atmosphere). So if the universe is like the Earth or like a balloon, then it does have a boundary, and something lies outside the "surface" of the universe (empty space? "nothing"?). But I understand that this analogy to a sphere is only an attempt to describe the nature of the universe, and we may be dealing with something other than the simple 3dimensional topology of a sphere. If this is the case then neither you nor anyone else can help me to understand the topology of the universe, because as of yet I cannot think outside 3 dimensions (or 4, including time)! But you did give a much more than satisfactory answer to the first part of my question, and the more important one, so for that answer I should have given you four stars or more. My apologies. 
Subject:
Re: Universe  finite or infinite?
From: andytheindoeuropeanga on 07 Feb 2005 12:32 PST 
Just another comment to patch up our relations. I recently reread your answer to my question, and I realize you used much effort and considerable explanation to try to describe to me the current understanding of the topology of the universe. So you should have gotten the four or five stars. However, some of your terminology is confusing to me, who does not have a physics degree. What is meant by M4,E3, E1, E.n, GTR, and STR? What do you mean when you say "I dare to say that a region of a flat space (E.n) is either bounded or infinite (Is that not a theorem, Mathtalk?)" I did not understand  do you mean we do not know whether it is bounded or infinite? What does "The light rays are all already on the models (are geodetics of that surface) and we just study which regions are connected (and so interact) and which are not." mean? I was confused by the wording. So you see, part of my problem with your answer was that you use language and symbology that is above my understanding, thereby causing me to believe that your answer was more complex than would be desired (and therefore worthy of fewer stars). But I suppose that's my fault, being a layman who is addressing you deities of intellect (and that's not meant facetiously). Thanks for all the info and references, I will delve into those sources that I can. 
Subject:
Re: Universe  finite or infinite?
From: mathtalkga on 08 Feb 2005 08:13 PST 
Mathematicians adopt the terms "sphere" and "disk" (in various dimensions) to distinguish between the thing that has no boundary (sphere) and the other thing whose boundary is the former! In twodimensions (plane) we have the 2disk, whose boundary is the ordinary circle (or 1circle if we which to be precise). In threedimensions there is the "solid sphere" or 3disk, whose boundary is the "hollow sphere" or 2sphere in "math talk". There is an intriguing pattern here which illustrates that the boundary of the boundary is empty. That is, starting with a disk in any dimension, its boundary is a sphere, and the boundary of the sphere is empty. "Bounded" is a word that is defined many ways in mathematics, depending on the context, and confusion about the meaning can lead to "paradoxes". For example, one is often introduced in a second semester of calculus to a solid of revolution which has finite volume but infinite surface area. In the absence of another definition, a bounded region of E^n (ndimensional Euclidean space, or "flat" space as hedgiega would say) means a subset for which some real number M > 0 exists such that every point is within distance M of the origin. Said differently, a region of E^n is bounded if and only if is is contained in some ndisk of finite radius M > 0 (centered at the origin). regards, mathtalkga 
Subject:
Re: Universe  finite or infinite?
From: andytheindoeuropeanga on 08 Feb 2005 09:49 PST 
I read your last comment, Mathtalk, and I concluded that I must be very unintelligent, because I didn't understand a word of it. No offense! 
Subject:
Re: Universe  finite or infinite?
From: mathtalkga on 08 Feb 2005 12:18 PST 
Okay, the disk is a nickel, and the circle is the rim on the nickel. The nickel (disk) has a boundary, which is the rim (circle). The rim itself has no boundary, or rather the boundary of the rim (circle) is empty. You can travel around the rim without ever reaching a "stopping point". If you move around inside the disk, however, by going far enough in any direction you must eventually hit the boundary of the disk. Having a boundary is then not the same thing (logically) as being finitesize. There are some finitesize things which have boundaries and some which do not have them, and likewise some infinitesize things which have boundaries and some which do not have them. However what hedgiega is pointing out (or hinting at) is that in some common cases (disks in "flat" spaces), the only way to avoid having a boundary is to be infinitesized, ie. to contain _all_ of ndimensional space. That's what our intuition that being finite = having a boundary is presumably based on. Cf. the "antinomies of pure reason" by Kant or earlier scholastic philosophers on the finiteness/infiniteness of time and space, and you'll see that the arguments hinge on the confusion of "bounded" (meaning finite) and "having a boundary" (meaning something one can cross, at least in a thought experiment). regards, mathtalkga 
Subject:
Re: Universe  finite or infinite?
From: andytheindoeuropeanga on 08 Feb 2005 13:59 PST 
OK, but if the boundary of the disk is the rim, then when you say "the rim itself has no boundary", that's equivalent, in my opinion, to saying "the boundary itself has no boundary" or "the surface of the Earth has no surface". Is that true? It would seem to me that the rim does have a boundary, since it occupies certain points in space which are limited in extent. The boundary of the boundary is itself, i.e. the rim extends no further out (from the centre of the disk) and no further in (from the rim itself) than its own width, which is no wider than a point in space, which is zero. The boundary occupies a limited, defined position in spacetime, and is therefore finite and bounded. If you mean that this boundary (the rim of the disk) has no boundary because its width is zero and therefore has no dimensions and no limit or boundary itself, well OK but it still seems to me that the boundary (the rim of the disk) occupies a limited position in space and is therefore confined within certain limits, and "limits" to me are the same as a "boundary". It's as though one had an orange peel which has a certain thickness (and therefore boundaries), but can be sliced ever thinner until its thickness approaches zero, at which point it is equivalent to the boundary of the orange. If its thickness is zero, does that mean that the orange peel no longer has a boundary? Or does the orange peel cease to exist, which implies that the rim, or the boundary of the disk, is a nonthing and has no boundary because it doesn't exist. This would be saying that things that don't exist have no boundary, which is selfexplanatory. But things that don't exist are not finite, so the rim of the disk would not be an example of a finite thing that has no boundary. Does any of this make sense? I started out saying that the boundary has a boundary but finished by saying that the boundary does not exist so it cannot have a boundary. Obviously I am still confused, despite your attempt to simplify your explanation of a boundless finite universe. I could edit this comment so that it is not contradictory but I prefer to let you see how my thinking went on this one, so that if you choose to answer it, you can refer to all my thoughts and correct them as necessary. And also, is a finite universe the same as a boundary (the rim of the disk), which is what seems to be implied to me, and which implies that the finite universe is equal to zero, or doesn't exist? Or is the finite universe rather the disk itself? Or, what is the disk of which the finite universe is the rim? You see, it's not straightforward to me. You can also see why I don't have a degree in physics or mathematics. Andy 
Subject:
Re: Universe  finite or infinite?
From: mathtalkga on 08 Feb 2005 14:25 PST 
Hi, Andy: Well, I think you see that I'm at least trying to make a distinction between the notion of being limited in size and having a boundary. I acknowledge that the confusion of these two concepts is the root of a lot of philosophical argument by very bright, wellintended folks over the ages. And I acknowledge that there are some common situations in which these concepts coincide. To make precise the equation: boundary of boundary = nothing one needs to limit the discussion to specific mathematical objects and a welldefined operation "take the boundary of X" which applies. I like this "equation" because it crops up in a variety of mathematical contexts, some quite dissimilar. In some geometric subjects (manifolds with boundaries) the notion of "nothing" is an empty set. In some algebraic subjects (long exact sequences) the notion of "nothing" turns into zero. No accounting for the tastes of mathematicians! regards, mathtalkga 
Subject:
Re: Universe  finite or infinite?
From: redshiftga on 10 Mar 2005 08:09 PST 
The universe is infinite. All this expansion is nonsense. I show here http://www.lyndonashmore.com that redshift is light interacting with photons in Intergalactic space. I also show "ashmore's paradox' that measured values of the Hubble constant H is just the electron in disguise. 
Subject:
Re: Universe  finite or infinite?
From: andytheindoeuropeanga on 10 Mar 2005 15:54 PST 
If that's what you truly believe, Vijay, I can't argue with you. I don't think anyone has the ultimate answer for the reason and origin of existence, so if your explanation satisfies you, then very well. 
Subject:
Re: Universe  finite or infinite?
From: mike123106ga on 14 Apr 2005 06:29 PDT 
God said "let there be light" He didn't say STOP! :) 
Subject:
Re: Universe  finite or infinite?
From: sanzyuga on 14 Apr 2005 12:18 PDT 
To follow up, its quite strange; the universe is finite temporarly; meaning that time itself had a beginning. Some people thing that because the universe can be thought of as infinite spacially, that there must be other civilizations in that infinite space. However, this is not correct according to current research. The universe is most uninhabitable for life due to some extreme conditions present in every other galaxy ever discovered. For more on this check out the book Rare Earth by Ward and Brownlee. 
Subject:
Re: Universe  finite or infinite?
From: ashurasaiga on 05 Sep 2005 03:35 PDT 
I think the easiest way to explain the boundary problem with spheres and disks is to use mathtalks nickel again, well a big circle anyhow. If you draw a straight line, in the sand on a beach, coz I?m feeling in a holiday mood, you can walk from one end to the other, then you have to stop or turn around and go back again, no matter what length, so long as its not infinite. If you draw a circle in the sand the same length and walk around it you never have to stop walking around it, but its not infinitely long, you can just walk around it an infinite number of times. As for your thing about beyond the boundary of the universe, i can see your problem with the whole boundary being the surface of the balloon, or in the case of my analogy above the fact that you can walk away from the circle to get an ice cream, analogies are a pain for most scientists, physics especially. People devote their entire careers (mostly philosophers) to trying to explain this stuff to the general public (who really do have a right to know, they're the ones paying for it, and they are the ones who potentially could benefit from it). Anyway, your quite understandable problem, cartoon characters and indeed any drawing are two dimensional representations of three dimensional things, but they are still two dimensional and can only really know two dimensions, they exist only in those dimensions the third doesn?t exist for them, so it can't really be considered a boundary if you can't move at all in it. When they use the sphere analogy you've got to stop thinking of yourself walking on top of it and imagine your self drawn as a cartoon character on it, totally unaware that a third dimension even exists, you just get fat in the two dimensions you know when it gets blown up in the three dimensions. The temporary infinity thing is a good point, Steven hawking went on about that in brief history and the guy who wrote the arrow of time. I think the point was would the universe look the same if you ran it backwards? If there was a big crunch then it might do, but with the whole accelerating universe thing going the big crunch seems unlikely as a potential fate of the universe. As to all the theories mentioned none have been proven, I don?t think anybody in physics will ever say anything is proven, that would imply we know everything about something, which we don't and I believe we never will (but then who knows?). And as for Lyndon Ashmore, anyone who invents a theory and names it after themselves really should be shot. Interesting as it is, logic is a tricky thing to understand fully and this guy really doesn?t. Godrealized, that?s stunning stuff mate, really cool 
If you feel that you have found inappropriate content, please let us know by emailing us at answerssupport@google.com with the question ID listed above. Thank you. 
Search Google Answers for 
Google Home  Answers FAQ  Terms of Service  Privacy Policy 