Physics question

[dazzztay]

If the universe is expanding - is the contents thinning?

If the dark matter that we know is there but cant detect is thinning due to the expanssion then will the speed of light change due to traveling through a less dense medium?

Where is Hawking or Krauss when i need them?

[sadako]

Yes it is thinning, and entropy will eventually cause the heat death of the universe unless gravity changes to make it start contracting.

[Maxf]

sadako said:

Yes it is thinning, and entropy will eventually cause the heat death of the universe unless gravity changes to make it start contracting.

In which point it could contract into a single point and create a big bang to start the cycle again.

[don4l]

Well, strictly speaking the Universe is not expanding. The space between things is expanding. Of course, this means that the Universe is expanding!

We have no evidence that Dark Matter exists. All we know is that galaxies are spinning faster than our limited understanding would predict. Instead of seeing that current theories are wrong, they have invented "Dark Matter".

Hawking cannot help you. He has said the Universe spontaneously appeared. Equal amounts of matter and anti-matter were created - so nothing happened at all! When asked why we couldn't find the anti-matter, he suggested that it must decay. Oooops!

Don
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[Pigeon]

Due to a fractional lack of perfection in symmetry 1000000001 parts of matter were created for every 1000000000 parts of antimatter. So most of it wiped itself out straight away but that little extra bit stayed behind and eventually ended up as stars and galaxies and pigeons.

[itsnotarace]

Wait until it expands so much it collides with another membrane. Party time.

[Mr GrimNasty]

Imagine space is a doughnut ring (don't get hung up on the actual number of dimensions - it's the concept that matters). Inside the ring are two points directly opposite, a matter and an antimatter universe big bang.
Each universe is expanding in both(all) directions from these points. One cannot see the other because it is around the corner. Eventually these two expanding universes will meet at 2 (all) points and vanish into each other forming nothing.

[Mr E]

Entropy always wins in the end

[dazzztay]

So if the space between everything is expanding then isnt the speed of light going to increase due to traveling through a less dense medium?

[Engineer1]

No I could be wrong here as this is high end weird physics but light travels through space time and if it needs to go faster then it stays at the same time and either space or time is altered to allow it to get there.

[dilbert]

Here's another possibility.

If the universe is expanding, then the middle is the same, and the edges are getting further apart.

The universe could be staying the same at the edges, and the middle contracting!

Either way it would look the same from the inside.

However it is, you have to think about it like a tube. On the left is the matter, on the right is the energy. In the middle is where we live.

Edited by dilbert on Wednesday 11th August 14:29