Expansion of the universe. What the hell?

I'm still trying to figure out alll this, and I am not very familiar with all the theories, so please help me out. According to many theories, our unkiverse is constantly expanding. Since people can not comprehend infinity, this theory makes sense. Forr the people that still can not comprehend infinity, but accept it, they will often leasd toward the theory that the universe is infinte. If the universe or "space" is expanding, what is it expanding into? Would matter be created during this expansion process? If matter was not created, then there would be nothing in the expansion, so space would be expanding, but it would be nothing expanding in nothing. How is this possible. since energy can not be created or destroyed, then how can the universe expand? Wouldn't this invlolve some sort of energy that does not exist because it is expanding into nothing?

 

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Oh, by the way, I just noticed the other thread regarding universe expansion, but mine kind of asks different questions, so i'll look at the other one too, also how do we know for sure about the expansion. Its not like we can see it expanding or anything. Is there some equation that can prove this?

 

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The `<b>red shifts</b>` of Galaxys are probably the best example that we have experimentaly, (the further away something is the more the light is `shifted` to-wards the red end of the spectrum), to show the universe is expanding.

But when ppl talk about the universe expanding, it`s not a `<i>normal everyday</i>` expansion...there is <i>nothing</i> that the universe is expanding <b>into</b>...

Perhaps it`s better to explain the expansion of space by imagining that all the particles/Galaxy's are <b>shrinking</b>...?

(<i>like the incredible shrinking man, we see everything getting further and further apart...</i>)

 

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No I don't like that explanation because it suggest then that there is a constant absolute size of the universe which there isn't! It IS actually expanding and ILikeSalt is right. Its expanding into nothing. He is also right that it does take energy to expand space and this is one of the reasons why the universe is cooling.

 

the way i understood the expansion of the galaxy is that its happened many, many, many, many, many, many, many, many times. the "big bang" happened and it spread and spread until it couldnt anymore then it retracted again... it happend like this though. imagine spraying water with your thumb over the nozzle straight into the air while standing on a podium. the water goes up and out and falls around you. now think of a huge, super powerful vacuum underneath the podium that faces down. the water falls past you and then gets sucked back up. only the vacuum was really just a water pump, and you were merely spraying the water it was sucking up. an endless cycle... except that when you think of it in a spacial manner, all matter was originally in a cingularity... it spread out until acceleration stops, it falls back in on itself to create another cingularity until god says "BORING!" and starts another one.... if he exists... but i dont wanna get into that. "STICK TO THE F*CKING SUBJECT!"

 

@John Connellan
yea, my suggestion was a bit, er, radical...

But have you proof that the universe is not an absolute size...?
(er, apart from the <i>stretching</i>of light in the redshift that basically proves it..)

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i haven`t ever come across anything to say otherwise...

The universe is cooling BECAUSE it`s expanding.


(And, I personally think it`s expanding into nothing, BTW)

 

I think that it's more correct to say that it isn't expanding into anything.

Unless it's infinite, of course.

 

Its a nice analogy but I don't think it is real so it might confuse people even further. Basically I don't think it should be explained like that to people. It is of course, impossible to prove anything!

Thats what I said

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Thanks for your support

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Nah, they're both correct scientifically. Grammatically is another thing! I said it like that so as not to confuse the people I was addressing. By saying it isn't expanding into anything some might take that as it isn't expanding. Know what I mean?

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If expansion is taking place at every point of space, is it taking place inside the matter too, between the atoms that form this matter, or even betwen the elementary particules that form the atoms ?
In the common analogy of an inflating dotted balloon, nobody is speaking of the variation of size of the dots. Same for the fruit cake analogy : are the fruits inflating with the cake ?
If so, am I inflating with the radius of earth and the whole universe ? (so few in a lifetime). Maybe it is mesurable with the official meter (defined using a radiation wavelength, related to physical constants inside an atom) if it is not inflating too ?

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I think the current consensus is...Yes.....u too are inflating at the same proportional rate as the universe. I don't know what proportional rate the universe is expanding at now, I'll have to Google it.

p.s. the official meter would be inflating too!

 

Bringing back blobrana's idea of shrinking... how do we know wheter the universe is shrinking or expanding? I'm not saying that the universe might be shrinking with everything getting closer. I'm thinking it as if the galaxies would be going appart and the universe would be "expanding", but the size of the universe to a external observer would still be the same. It's hard to explain what I have in mind. Ok...

Think of the universe as a balloon. The ballon is not expanding to an external observer. However, to an internal observer, the ballon is expanding. Things are getting farther and farther away. However, in reality, things are just getting "smaller" because the expansion is caused by the unwrapping of space-time. In other words: wrapped space-time looks like unwrapped one and instead of it being streching the fabric of space-time, it is actually unfolding.

Another way of seeing it. We are in a "black hole" inside another universe. This black hole had a singularity in its centre. The space-time was extremely folded (lots of space-time in a tiny bit of "space"). The singularity in this black hole exploded and it started to expand. For an external observer the black hole is not expanding. For an internal observer, the space-time is unfolding and expanding. We have the illusion that it is expanding into nothing.

This would result in a new kind of evolution: from stars to new universes.


I don't know. It's a crazy idea. But it's not bad to imagine it...

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Btw... this would explain the huge voids or "bubles" in our universe...

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>>>>I think the current consensus is...Yes.....u too are inflating at the same proportional rate as the universe. I don't know what proportional rate the universe is expanding at now....

i don't believe so. the forces between particles is stronger than the universal expansion.

 

I have often fallen back to this conclusion various times. I first based it upon the number line with the expansion/shrinking ranging from the postive side to the negative side. It's not as good as an analogy because of the 2D limitation, but it still gets the point across. "God" must of really been bored, aye? :bugeye:

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fred

 

I believe the latest result from the WMAP for the Hubble constant was 71+/-1...

 

It doesn't matter what forces are present in the universe. Forces act through space so if space is expanding then the particles will expand too along with the distance between them.

 

We would not be able to perceive the expansion anyway

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Electromagnetic?!? I thought that was only strong enough in small scales...

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Still, there are gravitational forces in local scales. For example, Andromeda is getting closer, and we are going in the direction of Virgo. So... I guess we see blueshifts when we look at those. If there are always blueshift in local scales, would the universe really be expanding? Or is the expansion just an illusion?

Also, another possibility. Just as in stars we have hydrostatic equilibrium with the net gas pressure and gravity, we might have a "doppler equilibrium" where the forces that expand the universe and causes redshift are as big as the forces that causes blueshift. In this scenerio the universe would have a definite constant size, and it would probably be rotating.