View deep space objects

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Re: View deep space objects

Post by aristarchusinexile » Tue Feb 03, 2009 6:24 pm

neufer wrote:
While there is NO "edge of our universe" there is certainly an "edge of our visible universe"

The "edge of our visible universe" is a two dimensional plasma sheet that existed some 13.4 billion years ago.

http://antwrp.gsfc.nasa.gov/apod/ap050925.html

There are certainly many other spots in our current, past & future universe that observe our own sun's alpha particles, protons & electrons as a part of their own "WMAP" 2D "edge of the visible universe" (... for many more our past is on the far side of their "WMAP" 2D edges).

But whether it is us or them being observed in a 379,000 year old plasma state;
the "edge of anyone's visible universe" is (, was and will be) certainly much closer in time to the Big Bang.
Neufer .. would you mind explaining to me the prevailing view of the Big Bang explosion. The statement that it is not thought of as a spherical shell surprises me, mostly because of images like this one. http://antwrp.gsfc.nasa.gov/apod/ap050925.html
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Re: View deep space objects

Post by aristarchusinexile » Tue Feb 03, 2009 6:32 pm

neufer wrote: Jerry: Now, the ending is kind of an option. I use the swirl. I like the swirl.
. I'm comfortable with the swirl. I feel the swirl is a great capper.
. [ Harry ] uses the [Z-]pinch, which I find a little presumptuous.
.
George: Is it a clockwise swirl?
.
Jerry: I prefer clockwise, but it's not written in stone.
------------------------------------
So, if the explosion is pinched, we may have Jerry swirling clockwise according to his pleasure, and George, maintaining a balance, swirling counterclockwise. I think this is probable, as the universe we observe is balanced. And Harry, do you say 'Zee' Pinch or 'Zed' Pinch down under?
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Re: View deep space objects

Post by aristarchusinexile » Tue Feb 03, 2009 6:35 pm

Ah .. getting the quote function down properly is a matter of using the "----". Of course, I was probably instructed in that a long time ago.
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Re: View deep space objects

Post by neufer » Tue Feb 03, 2009 8:56 pm

aristarchusinexile wrote:Neufer .. would you mind explaining to me the prevailing view of the Big Bang explosion. The statement that it is not thought of as a spherical shell surprises me, mostly because of images like this one. http://antwrp.gsfc.nasa.gov/apod/ap050925.html
Well, it can't be "a spherical shell" because the universe is FLAT:
Image
........................................................
It might be a LARGE DONUT however:

Image
-----------------------------------------
[b]http://en.wikipedia.org/wiki/Big_Bang[/b] wrote: <<If the distance between galaxy clusters is increasing today, everything must have been closer together in the past. This idea has been considered in detail back in time to extreme densities and temperatures, and large particle accelerators have been built to experiment on and test such conditions, resulting in significant confirmation of the theory. The observed abundances of the light elements throughout the cosmos closely match the calculated predictions for the formation of these elements from nuclear processes in the rapidly expanding and cooling first minutes of the universe, as logically and quantitatively detailed according to Big Bang nucleosynthesis.

Georges Lemaître was a pioneer in applying Einstein's theory of general relativity to cosmology. He suggested a precursor of Hubble's law in 1927. In 1931, he published his primeval atom theory in Nature. At the time, Einstein believed in a static universe and had expressed skepticism about Lemaître's 1927 paper. A similar solution to Einstein's equations, implying a changing radius of the universe, had been proposed in 1922 by Alexander Friedman, as Einstein told Lemaître when he approached him with the theory at the 1927 Solvay Conference. (Einstein had also criticized Friedman's theory.) Lemaître proposed his theory at an opportune time, since Edwin Hubble would soon publish his velocity-distance relation that strongly supported an expanding universe and, consequently, the Big Bang theory. Fred Hoyle is credited with coining the phrase "Big Bang" during a 1949 radio broadcast, as a derisive reference to a theory he did not subscribe to. Hoyle later helped considerably in the effort to figure out the nuclear pathway for building certain heavier elements from lighter ones. After the discovery of the cosmic microwave background radiation in 1964, and especially when its collective frequencies sketched out a blackbody curve, most scientists were fairly convinced by the evidence that some Big Bang scenario must have occurred.>>
-----------------------------------------
[b]Bad Cosmology[/b] wrote: -------------------------------------
1) The Big Bang happened at a point in space (where is it?)

Many people want to know where the big bang actually happened. But the whole concept of the Big Bang is that the universe is homogeneous, the same at all points. This could not be true if the Big Bang happened at one particular place. In fact the Big Bang happened everywhere at once (causing serious problems for causality, but then again, having it happen at different times in different places would be even worse!). In theory, all the points in the universe were at infinitesimal distances from each other at the very moment of the Big Bang (that's what is meant by calling it a "singularity"), but the whole concept of a singularity is unlikely to survive when we properly put quantum mechanics into the picture (which we don't understand how to do yet). This means there is no point trying to imagine what happened at time zero; but if you pick a moment or two after (say 10-40 seconds), then you are still in the earliest phase of the Big Bang, points are separated by finite distances (just much smaller distances than they are separated by today!), and the super-hot conditions are the same everywhere in the universe.
-------------------------------------
2) If the universe is spatially closed (finite), it will eventually recollapse, and if it is open (infinite), it will expand for ever.

This is a claim frequently made in textbooks and popular treatments of cosmology. It makes two unstated assumptions (i) that closed universes always have positive spatial curvature (ii) that there is no dark energy. Assumption (i) could be wrong if the universe had a `compact' topology such as a 3-Torus. These are closed but can have zero or negative spatial curvature. It would therefore have been better to say that a Universe with positive spatial curvature recollapses, while one with zero or negative curvature expands for ever. But this still makes assumption (ii), which is strongly contradicted by recent observations: dark energy is almost certainly present (in fact, it dominates the energy density of the Universe). Give dark energy, all four possibilities might occur (closed/recollapse, closed/expand forever, open/recollapse, open/expand forever). For what it's worth, the current best guess, assuming that the dark energy is a simple cosmological constant, is that the universe will expand forever, but it is too close to call on whether the universe is open or closed.
-------------------------------------
3) Even if the universe is closed, you can never see all the way round it, because by the time a photon travels all the way round the universe, the universe will have recollapsed in the Big Crunch.

This is another result which depends on the two questionable assumptions discussed in the previous item. With a large cosmological constant, a photon could travel round the Universe several times, even infinitely many times in the limiting case of Einstein's static, finite universe. Obviously our Universe is no close to the Einstein model. The best current data suggest that it might just be closed (to put it another way, it is closed but the radius of curvature R0 is much larger than the radius of the visible Universe). In this case the best bet is that even though it will last for ever, the Universe will expand so fast that a photon will only be able to reach a small fraction of the galaxies, even though it travels for ever at the speed of light. (Technically, the universe may have both a particle and an event horizon). However, this still assumes the simplest, `spherical' topology. If the topology is compact, the total size of the Universe could be much smaller, and light could travel around the universe many times (although the path would only close in certain special directions, thereby revealing the global anisotropy of such models). Current data is also consistent with a slight negative curvature for our universe, i.e. very large R0. Although compact (closed) negatively curved spaces can exist, they cannot be made much smaller than R0, and so they would behave very much like the spherical geometry, containing both a particle and an event horizon.
-------------------------------------
4) The observable universe might be the inside of a black hole.

This is sometimes said, meaning that the universe has an event horizon (a maximum distance to which we can ever send a signal). But in my view this stretches the sense of "black hole" beyond breaking point. In normal usage a black hole is a region of space-time described by something closely approaching a Kerr metric, which means there is a definite central singularity, and a definite event horizon within which all world-lines converge on the singularity. This is nothing at all like our nearly isotropic and homogeneous universe, where each point has a different event horizon.
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Re: View deep space objects

Post by BMAONE23 » Tue Feb 03, 2009 10:09 pm

neufer wrote:
aristarchusinexile wrote:Neufer .. would you mind explaining to me the prevailing view of the Big Bang explosion. The statement that it is not thought of as a spherical shell surprises me, mostly because of images like this one. http://antwrp.gsfc.nasa.gov/apod/ap050925.html
Well, it can't be "a spherical shell" because the universe is FLAT:
Image
........................................................
snip
Gee...Sure...another "Flat Universer"
:wink: :wink:

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Re: View deep space objects

Post by Chris Peterson » Tue Feb 03, 2009 11:02 pm

neufer wrote:Right; however, I believe that most people (myself included) would define
the OBSERVABLE universe as that part of the Universe that we see RIGHT NOW!
Yes. Did I suggest otherwise? Actually, the proper definition is slightly different: the observable universe is that which we can, in principle, see right now. That's because we should be able to observe somewhat beyond what electromagnetic radiation allows, since that limits us to the time when the Universe was opaque, which is still inside our zone of causality. It has been suggested that we might one day be able to see beyond this optical limit using gravity wave detectors. Still, most of the observable universe is currently accessible to us using EM.
And the "observable universe" [by MY definition] exists entirely on the space/time "surface"
of an imaginary light cone interior to the figure.

The apex of this cone is at the WMAP satellite position
while the base of this cone would lie on a circular patch
centered within the primordial plasma projection to the left
with the actual 2D WMAP represented by 1D circle of the cone's base.
That's completely different than the way I see it. I think the apex of the cone is t=0, and the base of the cone is t=now. The central axis of this cone is just time, and we can't see back in time. That "direction" isn't accessible to us, which is why I don't think the observable universe is another cone. Any perpendicular slice through the cone is a 2D projection of 3D space at some earlier time. Our present location is somewhere on the end disc, and is surrounded by a much smaller circular disc which defines our observable universe. The radius of that disc is 47 billion ly, which is the point where light from t=0 intersects the "now" disc, which is why we see things at that distance as the moment of the BB.
Chris

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Re: View deep space objects

Post by neufer » Tue Feb 03, 2009 11:13 pm

neufer wrote:
Chris Peterson wrote:
neufer wrote:1) What do you mean by "observable universe"
The observable universe is that part of the Universe that we can see (at least potentially), because we are causally connected to it. Roughly, that means because there has been time for light from it to reach us.
Right; however, I believe that most people (myself included) would define
the OBSERVABLE universe as that part of the Universe that we see RIGHT NOW!

So this is basically a semantics difference!
--------------------------------------------
[b] http://www.atlasoftheuniverse.com/redshift.html [/b] wrote:Because the universe is expanding, the question of the distance to a very distant galaxy is hard to answer.
It all depends on your point of view.

(2) Angular Diameter Distance - DA
In an expanding universe, we see the galaxies near the edge of the visible universe when they were very young nearly 14 billion years ago because it has taken the light nearly 14 billion years to reach us. However, the galaxies were not only young but they were also at that time much closer to us. The faintest galaxies visible with the Hubble Space Telescope were only a few billion light years from us when they emitted their light. This means that very distant galaxies look much larger than you would normally expect as if they were only about 2 or 3 billion light years from us (although they are also very very faint - see Luminosity Distance). Angular Diameter Distance is a good indication (especially in a flat universe like ours) of how near the galaxy was to us when it emitted the light that we now see.

(3) Comoving Distance - DC
The Comoving Distance is the distance scale that expands with the universe. It tells us where the galaxies are now even though our view of the distant universe is when it was much younger and smaller. On this scale the very edge of the visible universe is now about 47 billion light years from us although the most distant galaxies visible in the Hubble Space Telescope will now be about 32 billion light years from us. Comoving Distance is the opposite of the Angular Diameter Distance - it tells us where galaxies are now rather than where they were when they emitted the light that we now see.

(4) Light Travel Time Distance - DT
The Light Travel Time Distance represents the time taken for the light from distant galaxies to reach us. This is what is meant when it is said that the visible universe has a radius of 14 billion light years - it is simply a statement that the universe is about 14 billion years old and the light from more distant sources has not had time to reach us. Light Travel Time Distance is as much a measure of time as a measure of distance. It is useful mainly because it tells us how old the view of the galaxy is that we are seeing.
--------------------------------------------
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Re: View deep space objects

Post by Chris Peterson » Tue Feb 03, 2009 11:23 pm

neufer wrote:So this is basically a semantics difference!
I guess I'm missing something here. There is no difference, semantic or otherwise, because we're saying exactly the same thing with respect to the observable universe. Our only difference of opinion is with the interpretation of that cone-like diagram showing the history of the Universe.
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Re: View deep space objects

Post by neufer » Wed Feb 04, 2009 3:45 am

Chris Peterson wrote:
neufer wrote:So this is basically a semantics difference!
I guess I'm missing something here. There is no difference, semantic or otherwise, because we're saying exactly the same thing with respect to the observable universe. Our only difference of opinion is with the interpretation of that cone-like diagram showing the history of the Universe.
Forget the diagram.

I am talking about "Light Travel Time Distances - DT" to ancient galaxies & quasars now being observed in Hubble Telescope pictures; while you are talking about "Comoving Distances - DC" to the yet to be observed galaxies which evolved from those same ancient galaxies & quasars.
[b] http://www.atlasoftheuniverse.com/redshift.html [/b] wrote:Because the universe is expanding, the question of the distance to a very distant galaxy is hard to answer.
It all depends on your point of view.

(3) Comoving Distance - DC
The Comoving Distance is the distance scale that expands with the universe. It tells us where the galaxies are now EVEN THOUGH our view of the distant universe is when it was much younger and smaller. On this scale the very edge of the visible universe is now about 47 billion light years from us although the most distant galaxies visible in the Hubble Space Telescope will now be about 32 billion light years from us. Comoving Distance is the opposite of the Angular Diameter Distance - it tells us where galaxies are now rather than where they were when they emitted the light that we now see.

(4) Light Travel Time Distance - DT
The Light Travel Time Distance represents the time taken for the light from distant galaxies to reach us. This is what is meant when it is said that the visible universe has a radius of 14 billion light years - it is simply a statement that the universe is about 14 billion years old and the light from more distant sources has not had time to reach us. Light Travel Time Distance is as much a measure of time as a measure of distance. It is useful mainly because it tells us how old the view of the galaxy is that we are seeing.
--------------------------------------------
SN 1604 occurred 404 years ago, as YOU like to say, because it occurred 404 years ago
in the "Observable Universe" [as defined by MY DEFINITION of "Observable Universe"].

SN 1604 occurred 13,404 years ago, as I sometimes like to say, because it occurred 13,404 years ago
in the "Present Universe" [as defined by MY DEFINITION of "Present Universe"].

While you dismissed MY DEFINITION of "Present Universe" as not having any relevance whatever;
now suddenly MY DEFINITION of "Present Universe" is not only relevant
but it is YOUR own definition of the "Observable Universe."

I am totally baffled by this!! :shock: :roll:
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Re: View deep space objects

Post by Chris Peterson » Wed Feb 04, 2009 5:15 am

neufer wrote:I am talking about "Light Travel Time Distances - DT" to ancient galaxies & quasars now being observed in Hubble Telescope pictures; while you are talking about "Comoving Distances - DC" to the yet to be observed galaxies which evolved from those same ancient galaxies & quasars.
Okay.
SN 1604 occurred 404 years ago, as YOU like to say, because it occurred 404 years ago
in the "Observable Universe" [as defined by MY DEFINITION of "Observable Universe"].

SN 1604 occurred 13,404 years ago, as I sometimes like to say, because it occurred 13,404 years ago
in the "Present Universe" [as defined by MY DEFINITION of "Present Universe"].

While you dismissed MY DEFINITION of "Present Universe" as not having any relevance whatever;
now suddenly MY DEFINITION of "Present Universe" is not only relevant
but it is YOUR own definition of the "Observable Universe."
I don't think I've ever dismissed anything you said as having no relevance. You clearly misunderstood my earlier point that under SR, any event's occurrence time is when it is observed. I'm sure I also said that "now" is complicated and had different meanings in different contexts. I wasn't saying yours was wrong, just not exclusive.
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Re: View deep space objects

Post by neufer » Wed Feb 04, 2009 1:37 pm

Chris Peterson wrote:
neufer wrote:I am talking about "Light Travel Time Distances - DT" to ancient galaxies & quasars now being observed in Hubble Telescope pictures; while you are talking about "Comoving Distances - DC" to the yet to be observed galaxies which evolved from those same ancient galaxies & quasars.
Okay.
I think some of the Hubble folk got frustrated in impressing
lay people that their Deep Field images saw BOTH:

1) back in time 13 billion years and
2) back in space 13 billion light-years

so they decided to take advantage of the newly discovered expansion of the Universe
to claim that their Deep Field images saw nearly to the edge of the visible universe
47 billion light-years away:

http://www.youtube.com/watch?v=fgg2tpUVbXQ

which is a bit of a cheat IMO. :roll:
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Re: View deep space objects

Post by aristarchusinexile » Wed Feb 04, 2009 5:13 pm

Yes .. the present universe is not the observable universe because, for instance, we are seeing stars prior to their explosions, and are not yet witnessing other newly born stars, in effect of course we can never observe the universe as it is, only as it was .. our view being historical. This simplistic statement started out as my only contribution, but I have further examined the present gifted to us from Wikipedia, and added to my contribution. I find it interesting that the Wiki article begins with 'the present is the time....' and therefore not of space .. which to me confirms my speculation that spacetime is a myth .. that time and space are two seperate entities which at times in some places weave themselves together .. and that, really, can only happen in the smallest fraction of "here and now", whenever and wherever that is according to each Being conducting measurements .. which leads me to question if there can be a here and now where there is no being conducting measurement. It seems to me there must be here and know everywhere, and if it is true as some PHDs suggest physics proves, Time Travel forward and back is possible, then 'here and now' must be possible at all places at all times .. except when "there shall be no more time". However, like all of contradiction, the Wiki contradicts itself quickly, adding space to time for the present. The word present also is subject to definition, 'present instant', 'present era', 'present millenium', etc. These things all remind me again of how careful we must be in communication.

From Wikipedia - http://en.wikipedia.org/wiki/Present: " The present is the time that is perceived directly,[1] not as a recollection or a speculation. It is often considered as a hyperplane in space-time,[2] often called now, but it may also be viewed as a duration (see specious present[3][4]).

The present is contrasted with the past and the future. Modern physics has not yet been able to explain what we normally understand as the 'present'. There is both a time aspect and a space aspect to the present.

The direct experience of the present for each human is that it is what is here, now. Direct experience is of course subjective by definition yet, in this case, this same direct experience is true for all humans. For all of us, 'here' means 'where I am' and 'now' means 'when I am'. Thus, the common repeatable experience is that the present is inextricably linked to oneself.

In the time aspect, the conventional concept of 'now' is that it is some tiny point on a continuous timeline which separates past from future. It is not clear, however, that there is a universal timeline or whether, as relativity seems to indicate, the timeline is inextricably linked to the observer. Thus is 'now' for me the same time as 'now' for you on a universal timeline, assuming a universal timeline exists? Adding to the confusion in the physics view, there is no demonstrable reason why time should move in any one particular direction.

Adding substance to the supposition that the timeline view of 'now' may not hold the full picture, the qualities of 'now' or the 'present' in the human direct experience are very different to the qualities of past and future available through memory or anticipation. In the human direct experience, 'now' has a certain aliveness, reality and immediacy not present in our experience of past and future. Indeed, any experience is always happening 'now', even a re-living of some past event. Thus, there is a deep philosophical case for saying that the present moment is all there ever is, from moment to moment.

When comparing time in places separated by great distances, the notion of present becomes more tricky. For example, we visually perceive stars to be where they were when the light now reaching our eyes was emitted, because even though light travels at approximately 3 x 108 m/s it takes many years to reach us from distant sources. Thus, light travel time must be taken into account in such time comparisons."
Last edited by aristarchusinexile on Wed Feb 04, 2009 5:58 pm, edited 5 times in total.
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Re: View deep space objects

Post by aristarchusinexile » Wed Feb 04, 2009 5:30 pm

Thanks for this one, Neuf. By the way, the flat universe model fits the quote, "the heavens shall be rolled up like a scroll."
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Re: View deep space objects

Post by neufer » Wed Feb 04, 2009 6:24 pm

aristarchusinexile wrote:
Thanks for this one, Neuf. By the way, the flat universe model fits the quote, "the heavens shall be rolled up like a scroll."
. Revelation Chapter 6
.
[13] And the stars of heaven fell unto the earth, even as a fig tree casteth her untimely figs, when she is shaken of a mighty wind.
[14] And the heaven departed as a scroll when it is rolled together; and every mountain and island were moved out of their places.
Memorable quotes for A Mighty Wind (2003) wrote: ----------------------------------------------
Alan Barrows: And they had no hole in the center of the record.
.
Mark Shubb: It would teeter crazily on the little spindle.
.
Jerry Palter: No, you had to provide it yourself. They were still good records. Good product.
.
Mark Shubb: If you punched a hole in them, you'd have a good time.
.........................................................
Terry Bohner: This is not an occult science. This is not one of those crazy systems of divination and astrology. That stuff's hooey, and you've got to have a screw loose to go in for that sort of thing. Our beliefs are fairly commonplace and simple to understand. Humankind is simply materialized color operating on the 49th vibration. You would make that conclusion walking down the street or going to the store.
----------------------------------------------
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Re: View deep space objects

Post by aristarchusinexile » Wed Feb 04, 2009 6:32 pm

neufer wrote:"Humankind is simply materialized color operating on the 49th vibration. You would make that conclusion walking down the street or going to the store."
How about while canoeing on the French River in Canada with the Beach Boys?
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Re: View deep space objects

Post by Chris Peterson » Wed Feb 04, 2009 6:58 pm

neufer wrote:I think some of the Hubble folk got frustrated in impressing
lay people that their Deep Field images saw BOTH:

1) back in time 13 billion years and
2) back in space 13 billion light-years

so they decided to take advantage of the newly discovered expansion of the Universe
to claim that their Deep Field images saw nearly to the edge of the visible universe
47 billion light-years away:

http://www.youtube.com/watch?v=fgg2tpUVbXQ

which is a bit of a cheat IMO. :roll:
Nice video. The only thing I'd disagree with is that these distant galaxies are more like 30 billion light years out, not 47 billion light years. I do consider the co-moving distance as the generally correct value, since the light from these galaxies has genuinely traveled that distance over a few billion years to reach us. Nothing here I'd consider a "cheat".

I don't think I've heard any cosmologists argue that what we see from 13 billion years ago is 13 billion light years away. Perhaps in an old text book.
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Re: View deep space objects

Post by neufer » Wed Feb 04, 2009 8:28 pm

Chris Peterson wrote:
neufer wrote:I think some of the Hubble folk got frustrated in impressing
lay people that their Deep Field images saw BOTH:

1) back in time 13 billion years and
2) back in space 13 billion light-years

so they decided to take advantage of the newly discovered expansion of the Universe
to claim that their Deep Field images saw nearly to the edge of the visible universe
47 billion light-years away:

http://www.youtube.com/watch?v=fgg2tpUVbXQ

which is a bit of a cheat IMO. :roll:
Nice video. The only thing I'd disagree with is that these distant galaxies are more like 30 billion light years out, not 47 billion light years. I do consider the co-moving distance as the generally correct value, since the light from these galaxies has genuinely traveled that distance over a few billion years to reach us. Nothing here I'd consider a "cheat".
The light from these galaxies has certainly NOT traveled that distance over a few billion years to reach us.
Image
It is the quasars & galaxies themselves that have moved away
(and evolved into something else NOT seen in the Hubble Deep Field images)
in the few billion years it has taken the light to reach us.
--------------------------------------------
[b] http://www.atlasoftheuniverse.com/redshift.html [/b] wrote:Because the universe is expanding, the question of the distance to a very distant galaxy is hard to answer.
It all depends on your point of view.

(3) Comoving Distance - DC
The Comoving Distance is the distance scale that expands with the universe. It tells us where the galaxies are now EVEN THOUGH our view of the distant universe is when it was much younger and smaller. On this scale the very edge of the visible universe is now about 47 billion light years from us although the most distant galaxies visible in the Hubble Space Telescope will now be about 32 billion light years from us. Comoving Distance is the opposite of the Angular Diameter Distance - it tells us where galaxies are now rather than where they were when they emitted the light that we now see.

(4) Light Travel Time Distance - DT
The Light Travel Time Distance represents the time taken for the light from distant galaxies to reach us. This is what is meant when it is said that the visible universe has a radius of 14 billion light years - it is simply a statement that the universe is about 14 billion years old and the light from more distant sources has not had time to reach us. Light Travel Time Distance is as much a measure of time as a measure of distance. It is useful mainly because it tells us how old the view of the galaxy is that we are seeing.
--------------------------------------------
Chris Peterson wrote:I don't think I've heard any cosmologists argue that what we see from 13 billion years ago is 13 billion light years away. Perhaps in an old text book.
That's because it is basically a semantics issue.
"It all depends on your point of view."
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Re: View deep space objects

Post by Chris Peterson » Wed Feb 04, 2009 8:47 pm

neufer wrote:The light from these galaxies has certainly NOT traveled that distance over a few billion years to reach us.
I believe it has. Space has been expanding while it traveled, so the actual distance is much larger than the age of the object times c. Heck, the source of the microwave background- now over 45 billion light years away, was only a few million light years away from here (what would become here) when it was emitted. But it took 13 billion years to get to us.
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neufer
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Re: View deep space objects

Post by neufer » Wed Feb 04, 2009 9:32 pm

Chris Peterson wrote:
neufer wrote:The light from these galaxies has certainly NOT traveled that distance over a few billion years to reach us.
I believe it has. Space has been expanding while it traveled, so the actual distance is much larger than the age of the object times c. Heck, the source of the microwave background- now over 45 billion light years away, was only a few million light years away from here (what would become here) when it was emitted. But it took 13 billion years to get to us.
Space has been expanding while it traveled, so the actual distance is exactly the age of the object times c
instead of just the one billion light years away from here (what would become here) when it was emitted.
Image
Heck, that primordial plasma source of the microwave background has evolved
into UNOBSERVABLE galaxies that are now over 45 billion light years away.
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Re: View deep space objects

Post by astrolabe » Wed Feb 04, 2009 11:32 pm

Hey Moe! Hey Larry! Look...............an artifact of perception!

neufer wrote:That's because it is basically a semantics issue.
"It all depends on your point of view."
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Re: View deep space objects

Post by aristarchusinexile » Thu Feb 05, 2009 4:43 pm

astrolabe wrote:Hey Moe! Hey Larry! Look...............an artifact of perception!

neufer wrote:That's because it is basically a semantics issue.
"It all depends on your point of view."
Astro .. I haven't seen any other posts from you for a few days? Been on a Balsa raft in the Pacific?

Actually, what if the expanding universe has hit a wall and is bouncing back towards us?
Duty done .. the rain will stop as promised with the rainbow.
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Re: View deep space objects

Post by neufer » Thu Feb 05, 2009 10:27 pm

aristarchusinexile wrote:what if the expanding universe has hit a wall and is bouncing back towards us?
--------------------------------------------------
Pyramus: O wicked wall, through whom I see no bliss!
- A Midsummer Night's Dream > Act V, scene I
--------------------------------------------------
Image
Art Neuendorffer

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Re: View deep space objects

Post by astrolabe » Thu Feb 05, 2009 11:18 pm

Hello aristarchusinexile,
aristarchusinexile wrote:Astro .. I haven't seen any other posts from you for a few days? Been on a Balsa raft in the Pacific?
Well, not physically...........but as you know there are days when..............? :roll: 8)
aristarchusinexile wrote:Actually, what if the expanding universe has hit a wall and is bouncing back towards us?
There is a guy who proposed a collapsing-universe concept to explain the redshift in the apparent expanding universe. Interesting but hardly convincing IMOPO. One would, I would think, need a very impressive amount of DM anyway even to pull off the bounce/cyclical idea of a recycling universe. :shock: The "WALL" is unthinkable unless colliding galaxies are somewhere in that mind of yours as a good enough reason to pursue the thought as a kind of return wave. Am I on to you yet? :D
"Everything matters.....So may the facts be with you"-astrolabe

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Re: View deep space objects

Post by astrolabe » Fri Feb 06, 2009 12:09 am

Hello neufer,
neufer wrote:
aristarchusinexile wrote:what if the expanding universe has hit a wall and is bouncing back towards us?
--------------------------------------------------
Pyramus: O wicked wall, through whom I see no bliss!
- A Midsummer Night's Dream > Act V, scene I
--------------------------------------------------
Image
Isn't that Ezekiel in the image?
"Everything matters.....So may the facts be with you"-astrolabe

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Re: View deep space objects

Post by Chris Peterson » Fri Feb 06, 2009 12:35 am

astrolabe wrote:Isn't that Ezekiel in the image?
Nope, just a "missionary of the middle ages". The wood engraving is from the late 19th century (much later than it looks like), and first appeared in Flammarion's The Atmosphere: Popular Meteorology.
Chris

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