dordle-loddle Posted August 1, 2017 Posted August 1, 2017 Is the Universe infinite or just really, really big?
zapatos Posted August 1, 2017 Posted August 1, 2017 No one knows. Except for me, and I'm not saying. 2
Manticore Posted August 1, 2017 Posted August 1, 2017 I find it easier to think of the Universe as infinite rather than finite but unbounded which seems to be the other main option.
MigL Posted August 1, 2017 Posted August 1, 2017 The Observable Universe is finite. Anything outside of that may as well not exist, because it can never affect us in any way. 2
beecee Posted August 1, 2017 Posted August 1, 2017 7 hours ago, dordle-loddle said: Is the Universe infinite or just really, really big? As MigL has said the observable universe is certainly finite, and around 96 billion L/years in diameter. The WMAP probe showed the universe to be very nearly flat within small error bars, and that in the main points to an infinite universe, although a universe shaped like a torus which is also flat, is obviously finite. The other point to remember is the "flatness" as per WMAP did have error bars, albeit small, which in effect could mean that the flatness measured is simply an arc of a much larger closed universe. In any respect though the universe is pretty big or as I like saying [and have been taken to task over it] near infinite in extent and content.
StringJunky Posted August 2, 2017 Posted August 2, 2017 If our galaxy is scaled to 1mm the edge of the observable universe would be 480m or 480 000 adjacent Milky Ways away... that's pretty big.
Sensei Posted August 2, 2017 Posted August 2, 2017 15 hours ago, dordle-loddle said: Is the Universe infinite or just really, really big? You should specify what you meant by that. Infinite volume of the Universe.. ? Infinite quantity of protons in the Universe.. ? (therefor infinite mass) Infinite lifetime of the Universe.. ? (f.e. never ending expansion) Infinite quantity of versions of the Universe.. ? (Parallel Universes, Multiverses)
Airbrush Posted August 2, 2017 Posted August 2, 2017 (edited) The question is was our big bang everything? Or are there adjacent big bangs that are far beyond our visual horizon? OUR universe is probably finite in size simply because it is "easier" for a finite big bang to happen than an infinite one. Infinity is a very special animal. If the creation of the universe is comparable to pulling a rabbit out of a hat, an infinite universe is like pulling a unicorn out of that hat. Which is more likely? Of course I could be wrong, but this is something nobody can prove or disprove, until an adjacent big bang impacts the visual horizon of our big bang. Edited August 2, 2017 by Airbrush
seriously disabled Posted August 4, 2017 Posted August 4, 2017 If string theory/superstring theory/M-theory or any of those variants is correct then our universe could be part of a much much larger multi-verse. In fact our universe could be a grain of sand in something much much bigger. The problem is that we don't yet have a theory of everything (we don't even have a theory of quantum gravity) so from the perspective of physics we can't yet really know if universe is finite or infinite. I believe the universe is really infinite in extent but because of the laws of special relativity we will never be able to travel to another galaxy.
Airbrush Posted August 13, 2017 Posted August 13, 2017 (edited) On 8/4/2017 at 4:04 AM, seriously disabled said: If string theory/superstring theory/M-theory or any of those variants is correct then our universe could be part of a much much larger multi-verse. In fact our universe could be a grain of sand in something much much bigger........ I believe the universe is really infinite in extent ....... What makes you think the universe is infinite in extent when you previously said the universe could be "part of a much larger multiverse", which means our universe is finite, the multiverse is infinite, and we could be only one of many, maybe one of an infinite number of other big bangs? Edited August 13, 2017 by Airbrush
swansont Posted August 13, 2017 Posted August 13, 2017 7 minutes ago, Airbrush said: What makes you think the universe is infinite in extent when you previously said the universe could be "part of a much larger multiverse", which means our universe is finite, the multiverse is infinite, and we could be only one of many, maybe one of an infinite number of other big bangs? Being part of a multiverse does not mean our universe must be finite.
Airbrush Posted August 14, 2017 Posted August 14, 2017 On 8/12/2017 at 5:19 PM, swansont said: Being part of a multiverse does not mean our universe must be finite. How can a universe that has infinite size be contained within an infinite sized multiverse?
Strange Posted August 14, 2017 Posted August 14, 2017 21 minutes ago, Airbrush said: How can a universe that has infinite size be contained within an infinite sized multiverse? There are an infinite number of rational fractions between 1 and 2. And between 2 and 3. And so on for an infinite number of integers. More surprisingly, perhaps, there are an infinite number of real numbers between each pair of integers. And this infinity is larger than the infinity of integers. 1
Mordred Posted August 14, 2017 Posted August 14, 2017 (edited) 26 minutes ago, Airbrush said: How can a universe that has infinite size be contained within an infinite sized multiverse? This will mess you up most likely but it is possible to divide an infinite quantity an infinite number of times and each portion will still be infinite. The theoretical multiverse could be the same, so could our own universe. Edited August 14, 2017 by Mordred
Airbrush Posted August 14, 2017 Posted August 14, 2017 I'm still baffled, because on the scale of the universe, I don't see how you can stuff more than one infinite-sized universe into a multiverse. An infinite number of rational fractions between 1 and 2 is interesting but not a realistic model for universes within multiverses. The scale must remain constant. You cannot have tiny-sized universes (between numbers 1 and 2) that are also infinite in size.
DanTrentfield Posted August 14, 2017 Posted August 14, 2017 A question worthy of a thousand books trying to prove either side. The only way to concretely say yes or no is to have a view of the entire universe, and unless you happen to be capable of "Leaving Hotel California" (The universe), I am afraid that there is no answer that is true or false except one: Perhaps it is, Perhaps it isn't.
swansont Posted August 14, 2017 Posted August 14, 2017 1 hour ago, DanTrentfield said: A question worthy of a thousand books trying to prove either side. The only way to concretely say yes or no is to have a view of the entire universe, and unless you happen to be capable of "Leaving Hotel California" (The universe), I am afraid that there is no answer that is true or false except one: Perhaps it is, Perhaps it isn't. Or perhaps the Hotel Hilbert in this particular case.
DanTrentfield Posted August 14, 2017 Posted August 14, 2017 Just now, swansont said: Or perhaps the Hotel Hilbert in this particular case. Hah. Damn you mods sure have good memory. I admire your fun poking.
beecee Posted August 14, 2017 Posted August 14, 2017 The best one can say is that the Universe is at least near infinite in extent and content.
Strange Posted August 14, 2017 Posted August 14, 2017 3 hours ago, Airbrush said: I'm still baffled, because on the scale of the universe, I don't see how you can stuff more than one infinite-sized universe into a multiverse. If the universe is infinite, then "on the scale the universe"doesn't really mean anything. (Apart from the fact you seem to be basing your conclusions on what you can imagine or what "feels" right. Neither of which have much chance of working in this context.) Quote An infinite number of rational fractions between 1 and 2 is interesting but not a realistic model for universes within multiverses. Why not? Quote You cannot have tiny-sized universes (between numbers 1 and 2) that are also infinite in size. You can if they are infinite. The number line is an almost perfect analogy for this. 1
zapatos Posted August 15, 2017 Posted August 15, 2017 2 hours ago, beecee said: The best one can say is that the Universe is at least near infinite in extent and content. How exactly would you define "near infinite"? That sounds a lot like "a little bit pregnant". 1
beecee Posted August 15, 2017 Posted August 15, 2017 34 minutes ago, zapatos said: How exactly would you define "near infinite"? That sounds a lot like "a little bit pregnant". I believe it describes a state that is probably finite, but also humongously big and in realty beyond human measuring capabilities. I have been taken to task over it before, but I also believe the definition I gave, would be obvious to most people.
Carrock Posted August 15, 2017 Posted August 15, 2017 7 hours ago, Mordred said: This will mess you up most likely but it is possible to divide an infinite quantity an infinite number of times and each portion will still be infinite. That does mess me up. I thought each portion was finite. Or infinite.
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