The universe

[sahall]

What is the latest thinking on the expanding universe? Is it slowing down or what?

[jake-the-peg]

This was the greatest shock of the last few years.

It's accelerating.

You could have nocked most astrophysicists down with a feather when it became clear.

This is where the whole thing about "Dark Energy" comes from.

Have a quick Google for Dark Energy and you'll see

[sp1214]

If true, how can that be? Using a car as an analogy you can only accelerate by pushing the accelerator gradually to the floor. If it was a constant force it will remain at the same speed. So are you saying this dark matter has some explosive material in it?

[jake-the-peg]

You are assuming that the same rules that apply on your car apply to the Universe as a whole.

That is not necessarilly true.

For example there was a period of the Universe's history called the "inflationary" perios where it expanded many times faster than the speed of light.

The speed of light is a maximum for objects in our Universe, it says nothing about the universe itself.

Don't confuse Dark Matter with Dark Energy.

Dark matter is matter that we know exists from gravitational behaviour of things like Galaxies. We just can't see it and don't know what it is. There are a few good candidates but we don't know which it is.

Dark Energy is much more puzzeling it refers to the Energy that is causing this accelerated expansion, or the physics behind it.

The first is likely to represent some changes to the physics we know, the second may well be some significantly new science. Perhaps a fith fundamental force or a major modification to the law of Gravity at large distances or a better understanding of "vacuum pressure" something like that.

[sp1214]

Yes I should have said dark energy rather than matter.

[SarahJane12]

According to the Mayan calendar our galaxy will come into complete allignment on Dec 21, 2012, and everything ends after that.

[gardener2]

For example there was a period of the Universe's history called the "inflationary" perios where it expanded many times faster than the speed of light.

Could you expand on this?