scientist say that the universe is continuously expanding, which means its volume is getting bigger and bigger

Question

The qustion is , where is the new volume coming from?

Answer 1

There is actually an answer to this.

First, let me re-frame the question somewhat:
The Universe is continuously expanding, which means that the total volume that is filled with vacuum is getting bigger and bigger. Since there is a small, non-zero vacuum energy, where does the vacuum energy for this new volume come from?

Not quite the same question, but this new question does have a straightforward answer in General Relativity. The energy that fills the new vacuum comes from the pressure of all the other constituents in the Universe. The result is a net negative pressure that acts like anti-gravity on large scales: Einstein's cosmological constant, the so-called "Dark Energy". Because the dynamical effect of the negative pressure is to create even more volume, which makes for even more Dark Energy, the process leads to an exponential expansion.

Answer 2

You might think of it as being like the surface of a balloon that is expanding. This is a classic example used to explain the expansion of the universe. If you put dots on the surface of the balloon then no matter what dot you pick as being your viewpoint, all other dots will seem to be moving away from you. So space, only being three dimensions instead of two, is like the surface of that balloon. And just as no new material is being created to deal with the expansion of the balloon, you do not need a source for the increasing volume of the universe.

Now it is this expansion of space that carries the galaxies and everything else along with it. So space does exist and it is expanding. Galaxies and other things may have their own motions relative to space but it is the exapansion of the universe that is most evident over large distance scales and what we observe as red shifts in the light from these objects.

Answer 3

Actually that's incorrect. The volume is not increasing, the containment of the volume is expanding.

You can't think of the universe as a balloon being blow up with more and more air.

You have to think of a balloon with a little air in it that is super cold and warms up, thus expanding.

A small cube of liquid oxygen frozen inside a ballon would only make the balloon be an inch or so in size, but when that O2 warms up and becomes a gas the balloon will be 12" round do to expansion of the gas from conversion of solid.

As things warm up they expand.

Answer 4

The universe is a finite entity so it must have a maximum and a minimum size.
The universe began as a single space-time pulse,as the pulse continued the universe expanded and the pressure [density] of space increased.
The increase only happened for one-thirty billionths of a second.
A quantum effect disrupted the smoothness of space causing the emergence of matter.
Matter,energy and expansion reduced the density of space,and when the minimum density is reached space goes out of existence.
If the maximum radius of the universe is 6 billion light years as long as the pulses continue the universe will remain at it's maximum size.
When the pulses stop the universe will go out of existence in 6 billion years.

Answer 5

The universe is infinite in size. Two things are expanding. The size of the observable universe is expanding because that is determined by light travel. As we wait longer, we can see further, because the first light is always just reaching us. The other thing that is expanding is the distance scale. Space itself expands, so that the distances between galaxies, for example, are getting larger.

Answer 6

Space doesn't exist, so it has no volume. When scientists say that the universe is continuously expanding, they mean that the galaxies and other heavenly bodies of the universe are only drifting further and further apart.

Answer 7

I think you mean that scientists are saying the universe is constantly expanding based on the big bang theory. The big bang was an initial explosion and now the universe is expanding as a reaction to that. When an explosion occurs, things near the explosive are often times sent flying. I'm not really sure if that's correct, but I seem to vaguely remember OETA putting it something like that :-)

Answer 8

the volume comes from the expansion. the amount of matter in the universe is constant though. (except for mass/energy transfer)

Answer 9

i don't think expanding means more volume in this instance. a rubber band can be expanded but does not gain or lose volume.

Answer 10

Yes and no. There are also theories that the universe is only undergoing distortions in shape as it grows.