If the Universe is all there was, is, or will be then how can it have a finite age and size?

Question

I've heard that asking what happen "before" the big bang is a senseless question, since time did not exist. However, if the universe is everything-then its finite age and size poses relativity problems does it not?

1. Time came into existence at the big bang, and the Universe has a finitie age? 15 billion years relative to what? Itself?

2. The Universe is expanding. If the Universe is everything then how can it be bigger or smaller than itself? "If the professor shrunk everything else along with the kids, did he really shrink anything?"

3. The Universe was hotter than itself, and is cooling down. How can everything be hotter or cooler than itself?

How could the Universe begin time and be in-time simutaneously? Imagine if u had to move a clocks hand for time to move. It would take time to move the clocks hand. Paradox is it not?

Finally, do these problems come from observational evidence "Red shift, cosmic backround radiation" - Or does it come from a believe that nothing exists?

Answer 1

Cosmology can be hard to wrap your head around. Anyone who says that they truly understand things like general relativity, quantum mechanics and cosmology is probably lying. :D I know I don't, but I'll do what I can. I'll get back to your questions about relativity, but let me just address the other things first.



Asking what came before the beginning of time is like asking what is south of the south pole. We can work out the age of the Universe by examining the cosmic microwave background and applying some fundamental physics. Time was not stopped at the beginning of the universe so it did not need to be started. Space and time appeared simultaneously along with a whole lot of energy. Some cosmological hypotheses do have things before our universe though.



The universe doesn't have an edge and it doesn't expand into anything. Space itself is expanding, though it's only noticeable over distances of 100's of millions of light years. We can "measure" the size of the observable universe by knowing the age of the universe, speed of light and rate of expansion.



The temperature of the universe we know from a few things. Firstly absolute zero is a fundamental property of the universe. You can't get any colder than it. Secondly temperature can be related back to a number of physical properties.



Anyhow to get back to relativity. You seem to have the concept of it a little topsy turvy. Some new age gurus and people who don't understand physics like to say "Einstein said that everything is relative". That's a load of rubbish.



Relativity actually came out of a requirement for everything to be the same, more or less.



Einstein postulated (as others had done before him) that every observer in the known universe, no matter where you are or how fast you are going should agree on the same laws of physics. So they should measure the same speed of light, charge on the electron, mass of the proton etc. As far as we can tell this is the case. The laws of physics are the same everywhere.



Here is where things get kooky. For every observer to agree on the speed of light they may disagree on bunch of other things (such as the length of the spaceship the other guy is in as it zooms past) if they are travelling at different velocities. And that's where relativity comes from, from moving relative to something else.



Now your paradoxes may exist if you could define some sort of "universal zero" about which everything else moves. But you can't, it's impossible. As I said before, the universe is not expanding relative to anything. Space itself is expanding, uniformly and in all directions (as far as we can tell) so any one "zero" is just as valid as any other.



As things like the age size and temperature of the universe are fundamental properties of the universe related to the fundamental laws of physics every observer will agree on them, no matter how they're travelling relative to one and other.



Hope this helps. I have skipped enormous amounts of detail and simplified some things a lot. I suggest you grab yourself a copy of Stephen Hawking's "A Brief History of Time" and spend a couple of months reading it through a few times. That should go a lot further towards explaining what I talked about.

Answer 2

Answers (at least at a high level).



1. Time came into existence at the big bang, and the Universe has a finitie age? 15 billion years relative to what? Itself?



The universal expansion is along the "time" axis. Since we only perceive three dimensions spacially, we can't observe this directly, but we do see the effect. This is called time. So for arguments sake, let's say that you were a 5-dimensional creature instead of 3, you would see our universe as an expanding 4 dimensional "ball" or hypersphere as I like to call it. The expansion includes up/down, right/left, back/forward and time. The "length" of the time axis is between 13.5 billion units and 13.9 billion units. We call those units time, our 5 dimensional counterparts may call them something else and see time as just another unit analogous to our "length".



2. The Universe is expanding. If the Universe is everything then how can it be bigger or smaller than itself? "If the professor shrunk everything else along with the kids, did he really shrink anything?"



Frankly, I like Rick Moranis a lot more in "Strange Brew" and "Ghostbusters" than I did in "Honey, I shrunk the kids", but that's neither here nor there. The 4-dimensional, universal hypersphere is expanding into a higher dimensional "bulk". According the most recent M-Theory conjectures, this bulk consists of at least 11 dimensions, however, there is NO REASON to believe that there is any limit to the number of possible dimensions.



3. The Universe was hotter than itself, and is cooling down. How can everything be hotter or cooler than itself?



Don't quite know where you got this one, but let me try an analogy. The singularity that existed just prior to the big bang, included all energy that is in the universe today. Since it was much "smaller" it was much "hotter". This is analogous to the compression of a gas. The gas has a certain energy or "temperature" in a given volume, if you compress that volume, the temperature goes up (energy / unit volume)...



I hope I've addressed your last two unnumbered comments with my responses to the first three.



HTH - I just learned what that means from Charles!!! :) (Hope That Helps)...

Answer 3

Space-time is expanding. The material Universe is just along for the ride.



Space-time began. The matter in the Universe turned up later. About three minutes later, according to some calculations. Since some events before that took tiny fractions of a trillionth of a trillionth of a second, three minutes is an enormous length of time by comparison. Longer than the present age of the Universe in comparison to three minutes. Things are now a lot colder and slower than they once were.



The Universe was hotter than itself? Where did you get that? It was hotter once. The material of the Universe spread into expanded-space time. To do that it had to expend energy. That cooled it. It's the Joule-Thompson effect and it's exactly the same thing as in your refrigerator. Expanding gas gets cooler.



Cosmic microwave background is a major leg of the theory.

If the temp of the Universe is now 2.5K or thereabouts, and it's known at what temperature protons and neutrons start to break up, then you can get some idea of how long it took to cool down that far. Details of calculation? I don't know.



There is no logical connection between the fact that something, Universe or grain of sand, exists and it's size or duration.

Answer 4

Our perception of time came to exsistance at the big bang. we measure ou reality at the juncture at which the dispertion of all that we know took place in an historical point of view. All that we know of reality being time, space, matter, and energy.. All of theese things were originaly at a single point as a single entity. Untill they were scattered outward energy seperated from matter. the energy was at one point one single force until there became an imbalance and they were shattered into what we now call the basic energies. Magnetic, Higher Atomic, Lower Atomic, And gravity. If you think for one moment that we are smart enough to figure out the nature of space time, understand this we still dont know what gravity is. we Know what it does we Know that it occurs greater in cunjuction with greater mass. But we dont know why, the most basic of the energies, the only one still connected to matter, a remnent of the time before the big bang, and we still dont know what it is, except just to say it is a force. Within the bubble that is our reality, ( the universe), we measure time from the point that it started moving. when you put bateries in a clock it starts moving and at that point the clock begins to mesure time.the clock is not concerned with what time it was before it moved. To its limited perception there was no time before that and that is how we view exsistance, through the eyes of limited perception. This is selfish of us I know but it is all we have to base everything on. Of course there was something before our meaningless mesurement of expantion began.. Some call me a fool but my quest for truth brought me to this point..there must be a God. we cant see him because he wasn't in the bubble, to those who prefer to view exsistance from a limited point of view, Because he wasn't in the bubble at the time it started to move, He is not in our reality and therefore does not exsist. to me thats like saying because I was not present at the seperation of the first chromesome than I must not be male... But that is all what I have gleened from my study of the universe... You are welcome to have your own opinions... I encourage everyone to look for themselves... Just look with open eyes , and not through the specticles of limitation

Answer 5

they is no limit to the universe, only the limited if put on it throught our limited awareness.