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Dark matter is making the expansion faster.... 

Which is basically said to be the opposite of gravity. 

So the theory is something known as the big freez (u can't remember the name) 

Where even atoms will be split apart. 

But I belive in bug crunch more! 

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2 hours ago, Nova2000 said:

Dark matter is making the expansion faster.... 

Which is basically said to be the opposite of gravity. 

So the theory is something known as the big freez (u can't remember the name) 

Where even atoms will be split apart. 

But I belive in bug crunch more! 

Dark Energy  is proposed as the mysterious drive countering gravitational attraction in the Universe, and so accelerating its expansion.  Dark Matter - equally mysterious - is meant to account for irregular rotational properties of galaxies, amongst other things.

And a large majority  of the Universe's matter and energy is dark rather than familiar, ordinary matter.  Mysterious indeed!

Doug.

 

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What do you mean by irregular rotational properties? 

Edit

If dark matter is actually there. Then it has to occupy some space. So it should also be responsible for the dimming of light cause it blocks it.. My theory :)

 

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1 hour ago, cloudsweeper said:

Dark Energy  is proposed as the mysterious drive countering gravitational attraction in the Universe, and so accelerating its expansion.  Dark Matter - equally mysterious - is meant to account for irregular rotational properties of galaxies, amongst other things.

And a large majority  of the Universe's matter and energy is dark rather than familiar, ordinary matter.  Mysterious indeed!

Doug.

 

Doug, this paragraph seems to combine both expansion and gravity. Earlier you said that localized gravitational effects can overcome the expansion. I had always assumed that space in that local area was still expanding, but the movement of Andromeda towards our galaxy was sufficient to negate the effects. Is that correct? A bit like a person on an escalator. If they run fast enough against the direction of the escalator they can go in the opposite direction but the escalator (universe) is still moving (expanding)

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51 minutes ago, Nova2000 said:

What do you mean by irregular rotational properties? 

Edit

If dark matter is actually there. Then it has to occupy some space. So it should also be responsible for the dimming of light cause it blocks it.. My theory :)

 

Galactic matter apparently does not rotate at expected speeds.  

Other point: Dark Matter does not interact with radiation in the way ordinary matter does, i.e. it would not absorb light.

Doug.

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7 minutes ago, Stu said:

Doug, this paragraph seems to combine both expansion and gravity. Earlier you said that localized gravitational effects can overcome the expansion. I had always assumed that space in that local area was still expanding, but the movement of Andromeda towards our galaxy was sufficient to negate the effects. Is that correct? A bit like a person on an escalator. If they run fast enough against the direction of the escalator they can go in the opposite direction but the escalator (universe) is still moving (expanding)

Stu - this is all tricky stuff for sure!  As I understand it (based on reading only!), space is expanding.  On a large scale, Dark Energy repulsion "beats" gravitational attraction, but on smaller scales, gravity can still dominate.  So presumably the attraction between The Milky Way and Andromeda is greater than other factors, so we're on a collision course.  

I hope I'm right here - any trained cosmologists out there?

Doug.

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Is m31 and milkyway on the same plane? Or the 2 are coming in in 2 different directions? If we are on the same plane and one galaxy is moving faster then I'm sure it's something to do with dark energy. But if the galaxies are coming from 2 different directions then I feel it doesn't go well with the big bang theory. Ill try and put a picture later to make you'll understand if you can't make sense out of what I've typed :)

Rajesh 

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Dark matter causes a gravitational field. It is thus causes attraction or more correctly causes a depression in space time. The effects of gravity on a local scale are stronger than the effects of the force called dark energy. Thus Andromeda and the Milky Way will be drawn into the same plane. As far as is known there is no connection between dark matter and the force dark energy. 

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On 11/02/2017 at 18:13, mikeDnight said:

Einstein stated that space is a consequence of mass, so space doesn't exist where there is no mass. If that's true, then for space to be expanding at a rate close to or faster than the speed of light, then mass must be coming into existance at an unbelievable rate. At any rate, the energy needed to create this phenomenon has to be greater than the total energy in the known universe. Where is the energy coming from?

If the Big Bang actually happened, what made it go BANG!? And, if the Big Bang actually happened, then the rate of expansion would at best remain constant and not increase. What we could be seeing is not the expansion of the universe, but rather the deceleration of the universe! The further we look, the further back in time we see, and we don't see anywhere near that kind of expansion in our local environment, because its not happening today.

The further we look, we see more and more of the same thing, galaxies galore! We are way past the point of the Big Bang, yet the boffins are desperate to hold onto this nonsensical hypothesis. 

I'm probably on my own in believing that the red shift over vast distances is largely the result of energy loss from originally high energy photons, as they interact with subatomic particles and other photons, as well as being severely affected by gravitation over such distances. Effectively, a high energy photon emitted from a star at the edge of the known universe, loses energy along its journey, and so is not the same photon that began the journey, and spectrally moves towards the red end of the spectrum.

Mike

 

 

 

If Einstein said space was a consequence of mass it's news to me. My understanding is that he said that the curvature of spacetime was a consequence of mass.

We also need to be careful with the claim that space is expanding 'close to or faster than the speed of light.' The current estimate for the Hubble flow (the expansion of spacetime) is a paltry 71.9 kilometres per second per megaparsec. (Hubble, 2016.)  But note that the distance over which the expansion is measured is very important and has to be included in the figure. The expansion of spacetime is actually very slow when measured over a short distance, but all those little 'bits' of slow expansion add up over distance. Lots of little bits of slow expansion, over distance, eventually mean that two bodies sufficiently far apart are moving apart at more than light speed. But this would apply to any rate of expansion of spacetilme, however slow. For example, if space expanded at the grovelling rate of one millimetre per year over a million light years it would still be true that two bodies sufficiently far apart would be moving apart at more than light speed.

We must remember that these bodies are moving apart in a particular kind of way. When we normally see one body moving away from another it is because one or both of them have been accelerated. This is not the case with bodies moving apart due to the expansion of spacetime. Taking galaxies, each galaxy sees itself to be more or less at rest (ignoring local interactions) and sees all the others as racing away. They can't all be right!

Olly

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guys, I really recommend PBS SpaceTime videos on youtube. It gave me quite a good insight into BigBang theory and expansion of spacetime. Sometimes I had to watch the video twice to understand, or thrice, or five times after taking a break to think for a week or so :)

But it's worth it. I can now overwhelm friends with stuff they struggle to even begin to imagine :) 

Those videos complement nicely with simpler Hawking's books - like "Brief history of time" - (universe in a nutshell is still beyond my brain capacity) and after absorbing some books and videos on the subject, it starts to make sense and the information seems to join together to make a grander sense out of it.

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