99Percent

The cover of this month's Discover magazine shows the universe's size at 10 to -34 seconds, approximately like that of a cherry.

This seems to imply that the size of the universe is somehow relative to some "outside" scale of it, which is utter nonsense to me. The universe by its own definition is everything. At the very least it means that the matter inside this universe has been shrinking relative to other matter.

There is ample evidence that the universe is "expanding" and I don't deny this evidence. But wouldn't it really be that the matter in the universe is actually "contracting" and is receeding from the other matter? Wouldn't this in fact explain gravity as it would be the force of matter receeding from each other as space is made relatively larger?

And if the universe is expanding, where is it expanding to? There can't be anything "outside" of the universe, not even "empty space", whatever that could be. <img src="confused.gif" border="0">

Answerer

Well 99%, unfortunately the scientists believe that there is 'things' outside the universe, they even believe that there are other universes besides ours, that is to say, our reality is made of multiverse rather than a single universe.
As you have asked 'why can the matter be contracting?', well, that is because the present galaxries in our universe are moving outward instead of moving inward which they should be if they are contracting. So, apparently this is not case and so the scientists believe that space should be expanding. Besides do you feel gravitional force to be stronger? According the laws of gravitional force, this is what you should feel if everything is contracting to a point.

Malaclypse the Younger

99Percent

Not really. It's just a measure of how much space there is. We can have a finite quantity of space without that space being "in" another space.

Well... it's possible to use that frame of reference, but the arithmetic gets hairy, and weird things like momentum don't get conserved.

For instance, the earth's orbit isn't expanding, which is what you would expect to see if matter were merely shrinking. So the laws of physics would have to specify a conservation law that explained the constancy of the orbit. This would probably mean that momentum, mass * velocity, wasn't conserved; rather something else was conserved.

Probably not. But you might enjoy The Zen Gun by Neal Barrett, Jr. He speculates on a similar (but somewhat more elaborate) theory. But it's pure science fiction.

&lt;shrugs&gt; It's just expanding. There's just more space. There doesn't need to be something to expand into, that's just antropomorphic thinking.

Malaclypse the Younger

Answerer

I don't know that this is true. It's my understanding that some scientists are speculating that the presently observable universe might not be all there is, but there is no evidence yet of a greater "cosmos".

Not necessarily. It's probably possible to construct the laws of physics from the frame of reference where space is constant and matter is getting smaller. However, I would imagine that the math would be rather hairy.

Francois Tremblay

Welcome to the realm of everything 99%. Your questions have been pondered by everyone at some point (^_^)

I'm not sure that saying the universe expands is equal to saying that there is an "outside" to expand in (which is of course impossible). We can very well imagine a situation where this equality doesn't hold, as for example if you inflate a balloon. The surface has nothing to "expand in", and yet it does expand.

If matter contracted, then we should deduce that the universe started with complex structures such as atoms and is now only made of elementary particles. Yet we observe the contrary : the universe started with elementary particles which "coagulated" to make atoms and molecules. So it's pretty much disproven by the evidence that we have so far.

Koyaanisqatsi

99% of 1% is not that large.

Accordingly, 1% of 2% is HUGE.

It's all my fat relative from Festus.

Koyaanisqatsi

Franc, you're outdated, mon frer.

Superstring. Good vibes.

99Percent

Franc28 and Malclypse, I can see now where I was thinking wrong. The universe is not really expaning into anything, it is just expanding in relation to itself, there is more space, thats all.

I am just going to ramble for a bit and see if I can come up with an understanding.

Space is really just the relation between matter and time. So if the universe is expanding it means that there is really a dilation of time, ie, time is turning "slower" in relation to matter. Why is this? I can see that when you approach the speed of light, time contracts, therefore the universe would contract too, in fact as matter you would dilate to gigantic proportions as you approach the speed of light, no? This means that as time dilates, matter is actually becoming "smaller" in effect contracting, but what is causing time to dilate?

For non matter particles (eg, photons) time does not exist, therefore in relation to these particles the universe is in itself another particle because space does not exist as there is no time.

Man, I am even more confused than before...

Francois Tremblay

Tsh. Superstrings, superschmings (^_^)

eh

Malaclypse the Younger,

I've been reading up on inflation theories, and the multiverse idea seems to be hard to stop. The reason is, the mechanism needed for inflation is still present in our expanding universe, so it is very possible that the process will continue forever. This multiverse, is nothing more than our one universe that just so happens to be much more vast than we thought. I suppose you could consider chaotic inflation theories to be a marriage of the Big Bang and the Steady State model, with the difference being that the BB universe has a beginning.

Still, we have the problem of imaging 'what' this massive universe, or multiverse is expanding into. The same balloon analogy would be of help, if one could forget the air the balloon is growing into.