Expanding Or Shrinking?

[Jack Temmink]

Hi all,

 

Last days i'm walking with a question in my mind and im not smart enough to answer it.

So that's why I put it here where the smart people come.

 

The universe is expanding, and if it has a boundary we cannot say into what.

But if there's nothing behind the edge than we cannot say that we are expanding because relative to what is space expanding.

From our view space is getting bigger. But from the view of space mass is shrinking.

So like everything also an expanding universe is relative.

 

The only thing you can say is that the ratio space - mass is changing.

Bigbang 0% space - 100% mass

Now 99,99% space - 0.0000000000000000000042% mass

 

The question is: Does this has some logic in it?

 

 

 

 

[Strange]

But if there's nothing behind the edge than we cannot say that we are expanding because relative to what is space expanding.

 

The expansion of space does not require it to be expanding "into" anything. The universe is all there is, so there is nothing for it to expand into.

 

From our view space is getting bigger. But from the view of space mass is shrinking.

 

You can choose coordinates in which that is true.

 

The only thing you can say is that the ratio space - mass is changing.

 

You (i.e. the big bang theory) can say a lot more than that. That is why it is such a successful theory.

 

Also "the ratio of mass to space" does not make much sense. You can only have a ratio between things which use the same units. You are not just comparing apples with oranges, but more like the weight of an apple to price of an orange.

 

The question is: Does this has some logic in it?

 

A little bit. But it rather oversimplifies a fairly complex theory.

Edited May 17, 2015 by Strange

[Jack Temmink]

 

The expansion of space does not require it to be expanding "into" anything. The universe is all there is, so there is nothing for it to expand into.

 

 

You can choose coordinates in which that is true.

 

 

Thank you for your reply. See, here are the intelligent people

 

This is also what i ment. It doesn't have to or can't expand into anything so thats why you can also not say its expanding. It makes no difference if you say that the universe expanding or mass is shrinking, it has the same outcome.

Even from the start of the big bang because there's nothing else than the universe and there's no 'outside' measure it, only an inside..

[Delta1212]

Well, if everything is shrinking, you also need to proportionately weaken some forces and do things like slow the speed of light in proportion to the rate at which things are shrinking. You might be able to hash it out so that it all works, but it would certainly be a lot more complicated than simply assuming that space is expanding.

[Jack Temmink]

Well, if everything is shrinking, you also need to proportionately weaken some forces and do things like slow the speed of light in proportion to the rate at which things are shrinking. You might be able to hash it out so that it all works, but it would certainly be a lot more complicated than simply assuming that space is expanding.

 

hmmm,,, assuming is not to scientific is it?

 

I'm trying to see for myself how it's possible to see the difference between the two, expanding or shrinking, It's just a view of perspective without changing the rules of physics.

If space was an entity he wouldn't say he was getting bigger, he would see mass is getting smaller and visa versa, there is no other reference

Both are maybe even irrelavant because there's no way to tell the difference, like trying to find out who is moving, the airplane or the earth under it.

[Mordred]

Think in terms of thermodynamics.

 

PV=nRT as the volume increases energy density, pressure and temperature decreases. This is one evidence of expansion.

 

In the case of matter contraction the ideal gas laws also apply even for solids.

 

Now as a side note each of the four forces has a field strength that depends upon radius.

 

Then as mentioned you also have the speed of light and redshift effects to account for.

 

All these point to expansion, as opposed to matter contraction. As Delta mentioned its possible to make a coordinate system work but it will require more than just distance measures.

[Strange]

This is also what i ment. It doesn't have to or can't expand into anything so thats why you can also not say its expanding.

 

We can, and do, say it is expanding. There is a mountain of evidence for this.

 

It makes no difference if you say that the universe expanding or mass is shrinking, it has the same outcome.

 

It is not quite that simple, as already noted. If you make this transformation then you no longer have a constant speed of light, and you need to make many other changes. This makes the model much more complex. And it is also less intuitive (apart from, apparently, to a few odd people).

[Delta1212]

 

hmmm,,, assuming is not to scientific is it?

 

I'm trying to see for myself how it's possible to see the difference between the two, expanding or shrinking, It's just a view of perspective without changing the rules of physics.

If space was an entity he wouldn't say he was getting bigger, he would see mass is getting smaller and visa versa, there is no other reference

Both are maybe even irrelavant because there's no way to tell the difference, like trying to find out who is moving, the airplane or the earth under it.

 

Assumptions are unavoidable. The trick is making the fewest assumptions possible. Assuming that space is expanding explains everything that we currently see. Assuming that everything is shrinking requires several more assumptions in order to make it work.

[MigL]

The fact that looking at a distance is looking into the past provides proof that 'mass getting smaller' is not an accurate description.

As others have stated, there would be changes ( to fundamental forces and constants such as c and G ) that would be noted in observations.

 

The fact that there is no outside edge to the universe or anything for it to expand into, is also not an accurate description. The separation between things is increasing and that is perfectly consistent with a possibly infinite universe and observation. After all, an infinite number line going from 0 to infinity in units of 1, can easily expand by increasing the separation to units of 2. It is still infinite but hasn't expanded 'into' anything.

[jeffellis]

This universe is expanding as it spins on its axis. I think that each universe that is birthed from a stellar black hole is always expanding. It is difficult to fathom because there are more than 3 dimensions.

[Phi for All]

This universe is expanding as it spins on its axis. I think that each universe that is birthed from a stellar black hole is always expanding. It is difficult to fathom because there are more than 3 dimensions.

 

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Moderator Note

Hey, jeffellis, this is the mainstream science area. Please don't bring your pet concepts up here, we have students who trust these sections to help them with school. More rigor, please.