Astro-Bob.
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General question about the universe
#5327900 - 07/21/12 08:33 AM
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Hi Guys and Gals, Something I have never been able to get my head around is the scientists keep saying that if they look towards the centre of the universe, the more power they have in their scopes the further back they can look in time and the nearer to the big bang they can see.
Surely if it did all start with a big bang and the universe is expanding out from the point of the big bang, then the first stuff to have been created (Which would be the oldest stuff)is the farthest out? and that would be the stuff which was right at the point or just after the big bang? Looking towards the centre would be stuff that came much nearer the completion of the big bang? 
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bardo
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Re: General question about the universe
[Re: Astro-Bob.]
#5327912 - 07/21/12 08:51 AM
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There is no dimensional center. It is expanding in all directions. Observing through time means seeing the light of an object as it was emitted X amount of light years ago and the time it took to travel to your eye. So if something is 400 LR away when you view it you're seeing it as it was 400 years ago.
Here, this will help explain it better. Jump to about 8:50.
http://www.youtube.com/watch?v=7ImvlS8PLIo
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Qwickdraw
professor emeritus
Reged: 03/03/12
Loc: Ann Arbor, Mi
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Re: General question about the universe *DELETED*
[Re: bardo]
#5327920 - 07/21/12 09:07 AM
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MikeBOKC
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Loc: Oklahoma City, OK
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Re: General question about the universe
[Re: Astro-Bob.]
#5327921 - 07/21/12 09:08 AM
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This is always tough stuff to get our terrestrial three-dimensional minds around. It helps me to think in terms of distance and direction on the small scale (Jupiter or the center of the galaxy are over that way X miles/light years away) and to think of the universe as a whole in terms of time (X light years ago this happened.)
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Astro-Bob.
super member
Reged: 02/20/12
Loc: Warwickshire UK
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Re: General question about the universe
[Re: bardo]
#5327926 - 07/21/12 09:12 AM
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Hi Bardo, well I understand what you are saying, but if we are talking big bang then everything must be expanding out from that point. there must be a way to know which way to look otherwise how do you know that what you are looking at is light that is 400 years old or 4 million, well maybe red and blue shift answers what is moving in which direction, but what I say still holds, the first matter created would be the farthest out so if you want to look at near the big bang you should be looking at that, not towards the point of the big bang.
You can't say the light hasn't reached us yet, we are sat on a rock which is comprised of matter thrown out by the big bang, so if this matter has got here for us to sit on it, then the light must have passed by now.
I don't know at what part of the big bang the matter earth is made of was made, but I do know that older matter will be further out.
Things are relative for us to sit on this rock and look towards the centre and say we are seeing light that has taken 400 million years to get here, that light must have left the big bang 400 million years after us, as we are already here. therefore we are older and stuff that is past us and further out is older still and therefore matter that was created in an earlier part of the big bang.
I haven't looked at the video yet as I am listening to the Kevin smith show at the moment, but I will.
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bardo
scholastic sledgehammer
Reged: 09/13/09
Loc: US
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Re: General question about the universe
[Re: bardo]
#5327962 - 07/21/12 09:49 AM
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Hi Bardo, well I understand what you are saying, but if we are talking big bang then everything must be expanding out from that point.
Nope, there's no point of an "explosion." Anywhere or nowhere all things are moving away uniformly. You are the center. Move a million light years and you'll be in the center and see all things moving away from you uniformly. No matter where you look from.
Keep watching the whole video maybe it'll answer a few more things for you. Or leave you with more questions perhaps! But it goes into the time stuff too if I remember right.
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Jim Nelson
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Reged: 05/10/05
Loc: SE Michigan
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Re: General question about the universe
[Re: Astro-Bob.]
#5327988 - 07/21/12 10:06 AM
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"if we are talking big bang then everything must be expanding out from that point."
There is no such point! The Big Bang is not an "explosion" as we think of it. An explosion is a sudden expansion of matter traveling through space. The Big Bang is a sudden expansion of space itself. This is a huge difference.
You, right now, are currently at a point in space that can be directly "connected" in time to the Big Bang. So am I. So is someone in Galaxy M87 or some hypothetical person in a distant quasar. All of these points have equal priority to be called the center of the Big Bang, because in a some sense they all are the center of the Big Bang.
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David Pavlich
Transmographied
Reged: 05/18/05
Loc: Mandeville, LA USA
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Re: General question about the universe
[Re: Astro-Bob.]
#5328023 - 07/21/12 10:38 AM
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"Seeing" the beginning is getting tougher according to some theorists. There are those that theorise that the further out you go, the faster stuff is moving away to the point that it's faster than the speed of light. Does that infer that the stuff that's moving faster than light cannot be seen? I own a tennis shop and hated physics, so someone else needs to answer this one. 
David
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Astro-Bob.
super member
Reged: 02/20/12
Loc: Warwickshire UK
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Re: General question about the universe
[Re: David Pavlich]
#5328046 - 07/21/12 10:51 AM
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Wow! you have all certainly given me something to think about
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Astro-Bob.
super member
Reged: 02/20/12
Loc: Warwickshire UK
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Re: General question about the universe
[Re: Astro-Bob.]
#5328242 - 07/21/12 12:53 PM
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Ahhh Excellent, I have just watched the video and I am starting to get a grip on it, so because any point you wish to use as a reference appears to be at the centre and everything is expanding away from it, you can in fact look in any direction and the stuff which is furthest out will have been nearest the big bang and of course although this stuff will have once been very close to us, it is now a lot further out and light from any of it takes many light years to get back to us, but of course the further we can see the further effectively we are going back in time.
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Jim Nelson
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Re: General question about the universe
[Re: Astro-Bob.]
#5328401 - 07/21/12 03:01 PM
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As 1-sentence summaries go, that's pretty good! 
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bardo
scholastic sledgehammer
Reged: 09/13/09
Loc: US
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Re: General question about the universe
[Re: David Pavlich]
#5328419 - 07/21/12 03:15 PM
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"Seeing" the beginning is getting tougher according to some theorists. There are those that theorise that the further out you go, the faster stuff is moving away to the point that it's faster than the speed of light. Does that infer that the stuff that's moving faster than light cannot be seen? I own a tennis shop and hated physics, so someone else needs to answer this one.
David
Seeing the beginning is getting easier due to the cosmic microwave backround.
Yes that is Edwin Hubble's discovery. That velocity is proportional to distance. Things that are twice the distance for a given refernce are moving twice the speed, things that are four times as far are moving four times as fast, etc. At some point in the future we will not be able to observe anything in deep space from our vantage point. That rate is called the hubble constant.
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Darenwh
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Re: General question about the universe
[Re: bardo]
#5331092 - 07/23/12 10:35 AM
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Of course, then you have to ask another question. If nothing can go faster than the speed of light. But as things get farther from us they move faster away from us. Then, how can anything be farther away from us than the distance at which it is moving at nearly the speed of light as it cannot go any faster because it will then surpass the speed of light which is supposed to be impossible. In other words, there has to be something more going on or the edge of our universe has to be at that point beyond which, everything would have to accellerate to or faster than the speed of light for them to exist. Uh oh... thinking to hard... Getting a headache... 
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bardo
scholastic sledgehammer
Reged: 09/13/09
Loc: US
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Re: General question about the universe
[Re: Darenwh]
#5331760 - 07/23/12 05:23 PM
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As with entropy energy never ceases. It slows or spreads infinitely but never stops. With the acceleration it's doing the same.
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csrlice12
Postmaster
Reged: 05/22/12
Loc: Denver, CO
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Re: General question about the universe
[Re: Jim Nelson]
#5331900 - 07/23/12 06:53 PM
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"if we are talking big bang then everything must be expanding out from that point."
There is no such point! The Big Bang is not an "explosion" as we think of it. An explosion is a sudden expansion of matter traveling through space. The Big Bang is a sudden expansion of space itself. This is a huge difference.
You, right now, are currently at a point in space that can be directly "connected" in time to the Big Bang. So am I. So is someone in Galaxy M87 or some hypothetical person in a distant quasar. All of these points have equal priority to be called the center of the Big Bang, because in a some sense they all are the center of the Big Bang.
So, in essence, our "universe" could be just a busted diverticuli from some entities' intestinal tract?
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astroRoy
professor emeritus
Reged: 07/09/11
Loc: Southern Oregon
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Re: General question about the universe
[Re: Darenwh]
#5331939 - 07/23/12 07:13 PM
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Of course, then you have to ask another question. If nothing can go faster than the speed of light. But as things get farther from us they move faster away from us. Then, how can anything be farther away from us than the distance at which it is moving at nearly the speed of light as it cannot go any faster because it will then surpass the speed of light which is supposed to be impossible. In other words, there has to be something more going on or the edge of our universe has to be at that point beyond which, everything would have to accellerate to or faster than the speed of light for them to exist. Uh oh... thinking to hard... Getting a headache...
I think the going answer to this is that SPACE can move faster than light, carrying the objects faster than light.
Roy
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csrlice12
Postmaster
Reged: 05/22/12
Loc: Denver, CO
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Re: General question about the universe
[Re: astroRoy]
#5331943 - 07/23/12 07:16 PM
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Of course, then you have to ask another question. If nothing can go faster than the speed of light. But as things get farther from us they move faster away from us. Then, how can anything be farther away from us than the distance at which it is moving at nearly the speed of light as it cannot go any faster because it will then surpass the speed of light which is supposed to be impossible. In other words, there has to be something more going on or the edge of our universe has to be at that point beyond which, everything would have to accellerate to or faster than the speed of light for them to exist. Uh oh... thinking to hard... Getting a headache...
I think the going answer to this is that SPACE can move faster than light, carrying the objects faster than light.
Roy
So Star Trek had it right - Space: The Final Frontier
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astronz59
sage
Reged: 09/15/10
Loc: Auckland, New Zealand
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Re: General question about the universe
[Re: Astro-Bob.]
#5332082 - 07/23/12 08:56 PM Attachment (14 downloads)
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To have a truly balanced view, I recommend the following paper, which offers an alternative explanation for Red Shift and therefore addresses the implicit Freidman - Lemaitre conundrum of an ever expanding universe:
arXiv:0706.2885v2 [physics.gen-ph] 9 May 2008
Edited by astronz59 (07/23/12 09:13 PM)
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brianb11213
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Reged: 02/25/09
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Re: General question about the universe
[Re: astronz59]
#5332555 - 07/24/12 05:02 AM
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To have a truly balanced view, I recommend the following paper, which offers an alternative explanation for Red Shift
There are umpteen models which can explain the universe as we see it, probably more models than there are fundamental particles in the universe in fact.
Get a reasonable overview in John D. Barrow, "The Book of Universes" (Vintage, ISBN 978-0-099-53986-5). It's a popular descriptive book making few demands on mathematical prowess on behalf of the reader.
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astronz59
sage
Reged: 09/15/10
Loc: Auckland, New Zealand
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Re: General question about the universe
[Re: brianb11213]
#5333712 - 07/24/12 07:43 PM
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I have read John D. Barrow, "The Book of Universes" and can thoroughly recommend it, but it is a treatise on hypothetical mathematical models, with only a passing nod to observational astronomy. 
"The researches of many commentators have already thrown much darkness on this subject, and it is probable that, if they continue, we shall soon know nothing about it."
- Mark Twain
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