As the universe expands and more space is created, does another physical quantity diminsion to compensate?

Question

There appears to be a rule in physics that you cannot get something for nothing. The creation of space as the universe expands seems to contradict this rule unless some related attribute is running down

Answer 1

It isn't that more physical space is being created. Picture the universe's expansion like making a loaf of bread. There is dough and there is space (air) mixed into the dough. When you put a lump of dough in a pan and cook it, the dough begins to rise. You haven't added matter to the dough. The air bubbles in the bread have expanded making the loaf, as a whole, larger.

You have something that was very dense becoming less and less dense. That's simply the nature of things that expand.

I doubt that, at the end of it all, the universe will be as tasty or as crusty as a loaf of bread.

Answer 2

It is a good question you ask. Science believes that the Universe is expanding because of a Big Bang - hyper dense matter building up energy until it "exploded" sending the galaxies outwards expanding.
The problem is...how did the energy get there in the first place??
So there are theories that claim that the Universe will expand but that there are elastic forces that at one point will have it pull back in again, to collapse the way it was. Until the next Bang. A cyclic event, therefore.
This would satisty the compensation that you call for.
Of course nobody explains how this all begun, though...

Answer 3

Ok, the people above me that are saying that space itself isn't getting bigger are wrong according the Metric Expansion of Space portion of the Big Bang theory that is currently accepted by the majority of scientists.

Here is a section that deals with this concept from the article about this subject on Wikipedia:

The expansion of space is conceptually different from other kinds of expansions and explosions that are seen in nature. Our understanding of the "fabric of the universe" (spacetime) requires that what we see normally as "space", "time", and "distance" are not absolutes, but are determined by a metric that can change. In the metric expansion of space, rather than objects in a fixed "space" moving apart into "emptiness", it is the space that contains the objects which is itself changing. It is as if without objects themselves moving, space is somehow "growing" in between them.

So, apparently, the current scientific consensus is that that it IS spacetime itself that is growing. So, we're supposedly not seeing a red-shift in light from other galaxies simply because they are moving away from us. We are seeing the light red-shifted because the wavelengths of the photons are sort of being stretched as the photons move across the vast areas of expanding spacetime.

As for something else diminishing in the universe, I suppose the overall thermal value of the universe must be getting lower as the expansion takes place. However, I haven't heard of anything else that has been postulated to be diminishing.

Generally, the conservation law in physics says that matter/energy will always be conserved. So, this law doesn't really keep spacetime from growing.

Answer 4

No, the amount of space has always been the same, its just galaxies are moving farther apart from each other into space that already exists