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Author Topic: Should the older Universe appear smaller?  (Read 2468 times)

Offline dan@frankdan.com

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Should the older Universe appear smaller?
« on: 10/06/2013 01:48:23 »
Here's my question:

Given that the universe is expanding, and the farther things are, the faster they're moving away;
and that the farthest things we can see are about 13 billion light years away;
and that the universe is a little over 13 billion years old...

Well... aren't these distant proto-galaxies actually moving closer together as they approach the Big Bang, from our point of view?

and isn't the apparent speeding up actually a speeding backwards, toward the Big Bang, and not the spreading of objects in the universe further apart?

It boggles my mind that we can only extrapolate the actual current condition of the universe, since we can only directly observe its past.

Whew! Now I need to lay down for awhile.
« Last Edit: 10/06/2013 19:09:59 by chris »


 

Offline yor_on

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Re: Space and Time...
« Reply #1 on: 10/06/2013 12:17:25 »
Nice description Dan :) And yes, I think I see the idea there. That as we look at 'old light' also should see galaxies as they must have been at a Big Bang, contained in a smaller 'universe'. The universe we live in is described as isotropic and homogeneous. What that imply is that you could move to any place in this universe and expect yourself to see the same, looking into cosmos, as you do from here. So, anywhere you are you should see those 'old light (galaxies)' recede from you. And that goes back to how a Big Bang is thought to come to be.

At the beginning of it you had a 'instant inflation', that inflation is outside the physics we use to describe our macroscopic universe, where everything is decided from lights speed in a vacuum, your body's processes, as well as the information you get from that incoming light. And the universe must have been homogeneous and isotropic even there, and also being 'energy' at that time, if anything, not matter.

So, you have something able to inflate FTL, isotropically and homogeneous, containing 'energy'. From that came processes using light, becoming 'dust', becoming first generation stars, creating planets and later generations/types of stars, all as I get it. But the important point here is that it was all the same, happening at a 'same time' everywhere. So we have no measurable 'middle of the universe', or everything can be defined as being that 'middle' if one like. And if everything is the same, no matter where you stand, and we have a expansion between galaxies, then everything must recede from you, looking out. But sure, you're perfectly right in thinking that the further we look, the 'younger' that universe we see must become, although you won't see it 'shrink', as the direction at all times was first a inflation, later a accelerating expansion.
 

Offline dan@frankdan.com

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Re: Should the older Universe appear smaller?
« Reply #2 on: 17/06/2013 14:33:36 »
Not sure how my Subject got changed... originally it was Space and Time.

It's just, there's some combination of the age of the universe, the distance we can see, and the fact that the farthest things, the oldest things, are moving away from us at almost the speed of light... toward the Big Bang!

It's like we're surrounded by that original singularity.

weird
 

Offline yor_on

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Re: Should the older Universe appear smaller?
« Reply #3 on: 17/06/2013 16:01:53 »
You're quite right :) It's pretty weird to me too actually, and you described it very nicely. You could think of it as a lot of plum puddings treaded into each other, constantly 'at work', fermenting (if this now is the right words for it). All of them 'expanding' as you look back into the universe.
 

Offline Alan McDougall

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Re: Should the older Universe appear smaller?
« Reply #4 on: 18/06/2013 16:51:06 »

Hi,

Size is relative to an ant we humans are enormous, thus at the moment of the Big Bang Singularity was it not the largest thing in existence at that time?

Alan
 

Offline Bill S

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Re: Should the older Universe appear smaller?
« Reply #5 on: 18/06/2013 20:55:35 »
Quote from:  Dan
Not sure how my Subject got changed

It's FTL thread drift, or something like that.  :)

I have struggled long and hard with this one, so hopefully there will still be something to be said about it when I have a bit more time available.
 

Offline Alan McDougall

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Re: Should the older Universe appear smaller?
« Reply #6 on: 19/06/2013 17:40:12 »
Not sure how my Subject got changed... originally it was Space and Time.

It's just, there's some combination of the age of the universe, the distance we can see, and the fact that the farthest things, the oldest things, are moving away from us at almost the speed of light... toward the Big Bang!

It's like we're surrounded by that original singularity.

weird

In fact very distant objects like some primordial quasars are receding at greater than the speed of light, from our perspective, because they are embedded in space and space having no mass can and is thought to be expanding at greater than the speed of light, due to the acceleration of expansion of our universe. Which sadly will lead to its ultimate heat death, in the unimaginable distant future

Alan
 

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Re: Should the older Universe appear smaller?
« Reply #6 on: 19/06/2013 17:40:12 »

 

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