# Thread: Why is space accelerating?

1. ## Why is space accelerating?

I have just watched a programme about Jocelyn Bell Burnell who discovered Pulsars in the 60's .. very interesting indeed.

One of her last comments were about scientists of the present/future and questions they will be finding the answers to .. Such as why is space accelerating faster than at any time in the past?

Like i said .. Knowing very little on the subject, i have just grabbed a pen, done some freaky little diagrams, and made notes .. So if you know the answers to any of these questions then i would be grateful for your insight in this matter ..

Could the universe a particular shape that could explain the acceleration?
Is it a shape at all?

As energy is being used, you'd expect to an extent, de-acceleration over a period of time .. That would be the simplest of answers .. This is wrong or inaccuate to them .. But if something is churning up all this energy (both my index fingers are going in a circular motion there) couldn't the motion build up to actually increase acceleration?

Or could possibly as the big bang happened at a particular point and has been extending outwards since .. Could not maybe the space it's now entertaining be filled with something different (maybe denser) than what it has in the past?

And lastly .. the big bang happened 14 - 15 billion years ago .. If we have gained the knowledge to witness the beginning of time (big bang) then why can't we go past that to see just where the universe actually ends???
That is very black and white, i know.

A stupid question is only one that is never asked ..

Thank you.

2. I've done subjects on it, but I'm not sure if they know why it is expanding, just that it is (or they propose that it is because it is a simple explanation which agrees with observations).

By expanding they actually mean space is expanding like a balloon. So a metre in space stretches to be more than a metre some time later. It's a little freaky. Some objects a long, long way away appear to move away from eachother faster than the speed of light because of it also. I don't know, but this might limit how far back we can see with telescopes too.

I'm about to go to work, but looked on wikipedia for you and this is a start on it. The general relativity stuff about metrics might be confusing, but the history and explanations are an easier read.

3. I believe, they believe, it is related to the great degree of dark matter that is present in the Universe.

4. It's often considered one of the greatest mysteries. There is no real 'this is why' theory that is widley accepted.

I'd suggest picking up a book called 'An Elegant Universe'

The beginning of the book deals a lot with relativity, time dialation, the properties and theories of the universe on a grand scale, etc.

5. I think, and this is a tentative think, that Dark Energy is used primarily to explain this phenomena. Dark Energy has a constant energy density and permeates the fabric of spacetime, it apparently accelerates the expansion of the universe due to it having negative pressure.

6. ## The universe will disappear

What is extraordinary is that the universe is accelerating away from us at such a rate that eventually the whole universe, except our Milky Way held together by gravity, will pass beyond our event horizon and so become invisible.

So in the future there will be no evidence the Big Bang ever existed.

So it is only in this special time of the universe that we can know where we came from and where we are going.

7. Eventually, dark matter will overtake matter. The entire mass of the universe will compress into a very small space and become unstable.

Then *big bang!* a whole new universe is born! Ripping like a wave down a string, and the song continues.

8. Space isn't accelerating, its expansion is as far as we know. Accelerating space assumes that space can be compared to another frame of reference as in 'relative to x'

9. Originally Posted by EcK
Space isn't accelerating, its expansion is as far as we know. Accelerating space assumes that space can be compared to another frame of reference as in 'relative to x'
SPACE.com -- Deformed Galaxies Confirm Universe's Acceleration

Relative to deformed galaxies? Not sure if we're all using the term "acceleration" in the same context? But it's been a widely accepted topic in Astronomy for many...many years and a phenomena originally observed and speculated on by Hubble before any of us were born.

10. Originally Posted by sLiPpY
Eventually, dark matter will overtake matter. The entire mass of the universe will compress into a very small space and become unstable.

Then *big bang!* a whole new universe is born! Ripping like a wave down a string, and the song continues.
We now know this is entirely wrong and the universe is not only expanding but the expansion is accelerating and the acceleration will not slow or reverse.

And interestingly it was couple of Australian astronomers just down the road from me at the Stromlo Observatory, in Canberra, Australia, who made this discovery only recently.

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