Moderators: gmalivuk, Prelates, Moderators General
Ixtellor wrote:As in, if you used all the information in the universe, you could count to X, therefore X is a finite number? (In that infinity is just a man made concept, and that it does NOT exisit in the physical universe)
Magnanimous wrote:(fuck the macrons)
gmalivuk wrote:But most of it (an infinite amount, in fact) will be forever inaccessible due to the speed of light.
gmalivuk wrote:There is probably infinite matter, which means infinite information, yes. But most of it (an infinite amount, in fact) will be forever inaccessible due to the speed of light.
In the observable universe, yes. But it doesn't just end there.Ixtellor wrote:I thought that the we knew the mass of the universe(approximation), and that led me to believe that matter was finite.
Ixtellor wrote:gmalivuk wrote:There is probably infinite matter, which means infinite information, yes. But most of it (an infinite amount, in fact) will be forever inaccessible due to the speed of light.
I have never heard that there is infinite matter before. I thought that the we knew the mass of the universe(approximation), and that led me to believe that matter was finite.
Magnanimous wrote:(fuck the macrons)
eSOANEM wrote:When most people (particularly popular science books and tv shows) say "the universe" they strictly mean "the observable universe". AFAIK, most modern cosmologies have an infinite universe of which only a part is visible (due to c being finite) and, assuming the universe is homogeneous (which seems to be a fairly valid assumption given that the observable universe is pretty homogeneous), the fact that there is a non-zero mass density in the observable universe would require that the universe contains an infinite amount of mass.
Well strictly speaking, we don't know what's beyond the observable universe, because it's unobservable. Also, there's no "edge" to the universe, just an edge to the region of it that we can observe.Ixtellor wrote:1) Is it due to the universe expanding faster than C, thus mass at the edge of the universe can never reach us? Or does the expanding universe only describe the observable universe and its the observable universe that is expanding faster than C?
Of course. If it's not part of the observable universe, we can't observe it. The background radiation is the remnant of what the universe looked like when it first became transparent to photons, and so it's impossible to look farther back in time than that.2) I know we can look into the past due to background radiation.. is that only of the observable universe?
Something like that, yeah. Though generally when physics comes up with infinities in quantities like density, the consensus is that we just don't understand the whole picture yet, rather than that the density there is actually infinite.3) How about this... did the Big Bang singularity contain infinite mass/matter? And we just can't see it all now because its further out than C will allow the evidence of it to get back to us?
Ixtellor wrote:eSOANEM wrote:When most people (particularly popular science books and tv shows) say "the universe" they strictly mean "the observable universe". AFAIK, most modern cosmologies have an infinite universe of which only a part is visible (due to c being finite) and, assuming the universe is homogeneous (which seems to be a fairly valid assumption given that the observable universe is pretty homogeneous), the fact that there is a non-zero mass density in the observable universe would require that the universe contains an infinite amount of mass.
Correct me if I am wrong, but it sounds like your saying that there is infinite mass but its outside the known(observable) universe because any information out there (light, mass, radiation) is so far away it can't reach us because even traveling at the speed of light, there has not been enough time to reach us from the GREAT distance from which it is.. er originates.
That leaves me with lots of questions.
1) Is it due to the universe expanding faster than C, thus mass at the edge of the universe can never reach us? Or does the expanding universe only describe the observable universe and its the observable universe that is expanding faster than C?
2) I know we can look into the past due to background radiation.. is that only of the observable universe?
3) How about this... did the Big Bang singularity contain infinite mass/matter? And we just can't see it all now because its further out than C will allow the evidence of it to get back to us?
Magnanimous wrote:(fuck the macrons)
eSOANEM wrote:Expanding from gmal's post:
When most people (particularly popular science books and tv shows) say "the universe" they strictly mean "the observable universe". AFAIK, most modern cosmologies have an infinite universe of which only a part is visible (due to c being finite) and, assuming the universe is homogeneous (which seems to be a fairly valid assumption given that the observable universe is pretty homogeneous), the fact that there is a non-zero mass density in the observable universe would require that the universe contains an infinite amount of mass.
That's what a non-zero density *is*...Scyrus wrote:And what if the density had a positive real number as a value?eSOANEM wrote:the observable universe is pretty homogeneous), the fact that there is a non-zero mass density in the observable universe would require that the universe contains an infinite amount of mass.
Scyrus wrote:Which would imply that the universe expanded from a singularity with infinite mass into an infinitely vast volume with infinite mass in it in a finite amount of time, right?
Scyrus wrote:Which raises my actual question. Why are we assuming there is either infinite space or mass? Or both? What is wrong with a finite universe that expands at a finite and has finite mass? Sure, it may have the ability to expand infinitely or contract eventually, but why assume it is already infinite?
Scyrus wrote:And the mass? I mean, the law of conservation of energy dictates that the total amount of energy (and mass) is a constant.
Scyrus wrote:Which would imply that the universe expanded from a singularity with infinite mass into an infinitely vast volume with infinite mass in it in a finite ammount of time, right?
Which raises my actual question. Why are we assuming there is either infinite space or mass? Or both? What is wrong with a finite universe that expands at a finite and has finite mass? Sure, it may have the ability to expand infinitely or contract eventually, but why assume it is already infinite?
And the mass? I mean, the law of conservation of energy dictates that the total ammount of energy (and mass) is a constant.
Scyrus wrote:And what if the density had a positive real number as a value? Wouldn't assuming an infinite universe with infinite mass *out* of our observeable part, where there are regions with clearly non-infinite mass imply that the universe is heterogeneous instead?
Magnanimous wrote:(fuck the macrons)
All Shadow priest spells that deal Fire damage now appear green.
Big freaky cereal boxes of death.
I don't like this statement. It's far better to say that the universe is very, very close to being flat, but it could still be open, closed, or flat; the error bars are still too large to definitively say one way or the other, and different models give different answers. One interesting thing is that the universe had to be extremely close to flat to even get to this point; if it had substantial curvature, the expansion would have either totally run away by now, or it would have recollapsed long ago. IIRC, to get to where it is today, the universe had to be within one part in 10^12 of being perfectly flat or somesuch early in its history.Yakk wrote:We cannot detect any such curvature -- so either the ball is ridiculously (and I mean ridiculously) large, or the universe is actually flat.
Yakk wrote:By topology -- if you have space that looks "locally flat" and n-dimensional (like ours), for it to have no edge that folds back on itself requires that it be "curved" like a ball. There doesn't appear to be a way around it. Now, the larger the ball, the smaller the curvature.
We cannot detect any such curvature -- so either the ball is ridiculously (and I mean ridiculously) large, or the universe is actually flat.
All Shadow priest spells that deal Fire damage now appear green.
Big freaky cereal boxes of death.
gmalivuk wrote:What seam?
Ixtellor wrote:So if it exploded(expanded) from infinte size to infinite size.... I am confused.
I assume this has something to do with density, but I thought that meant that the universe pre-big bang was small because it was infinitely dense.
Some clarification is needed for this layman. Also, if it was infinite in size (the singularity) what does that... er look like.
Magnanimous wrote:(fuck the macrons)
Yakk wrote:In a non-orientable universe, wouldn't "going around the universe" turn matter into antimatter?
Maybe not, now that I think about it.
Yakk wrote:By topology -- if you have space that looks "locally flat" and n-dimensional (like ours), for it to have no edge that folds back on itself requires that it be "curved" like a ball. There doesn't appear to be a way around it. Now, the larger the ball, the smaller the curvature.
We cannot detect any such curvature -- so either the ball is ridiculously (and I mean ridiculously) large, or the universe is actually flat.
mfb wrote:That looks like something you could modify to an infinite universe just by coordinate transformations. And as General Relativity teaches us, coordinates are arbitrary and without physical meaning.
If the universe changes in some way near the border region, we would live in a special place (not near the border), which is possible but may be unlikely, depending on your universe structure.
Users browsing this forum: bouxubsids, thoughtfully and 6 guests