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[Andir]

Ah, I do remember something about this. Perhaps you know more than I do here, but I thought it was a little different than what you're describing. I thought everything was visibly moving apart because of expanding space. Thus if we crunched it back down, we would have the distinct impression of everything moving toward us still (until, you know, things collided with us). What you're describing though sounds more like a funky version of a steady state, as it wouldn't matter whether the universe was expanding or contracting, since we'd never know the difference. Is what I'm saying makign any sense? because now I'm not so sure. Maybe I need to ask Neil DeGrasse Tyson....

With most of it, there's still debate and some unknowns.  The current trend seems to be finding evidence that supports Einstein's formulas and debating against that is like moving the Earth.

Hubble’s law is consistent with a general expansion of the space between galaxies (or galactic clusters), and is not a particular characteristic of the galaxies (clusters) themselves. This statement means that the galaxies themselves are not changing in any way; only the regions between them are expanding with time. If the expansion is run backward (as can be done with mathematics), then it would appear that, very long ago, all the matter of the universe was once compacted into a relatively small volume from which it was hurled outward by some titanic force. This idea is the basis for the Big Bang.

I believe Andir just got it wrong, as we would surely notice the difference in the size of the universe, should we get back to the beginning of time. The density would be much higher, eventually reaching infinity(at the singularity), yet despite this, the total "amount" of space could very well be infinite even then.

That's the general idea, but question that and you get what I said... hand-waving.  Nobody wants to commit to identifying the general direction of expansion and identifying where the center is.  Even if all galaxies were expanding away from each other, you should be able to compare a specific set of galaxies and identify a focal point for all their expansion vectors.  Everyone is firm in stating that it's happening, but they state it's not important/impossible to find the center.  They all attribute the state it is now to the general location of things billions of years ago and credit the redshift to the expansion of space/time between us, but not within our galaxy or other factors.  (ie: 10 billion years ago, the Milky Way was in the same relative space compared to Andromeda just like raisins in a loaf of dough.)

Gah... I'm done discussing this. (again!)

[Il Palazzo]

Man, you shouldn't stop discussing the subject, as you obviously don't understand the ideas behind it. Unless you're o.k. with criticizing the stuff on the ground of your own ignorance.
Nobody is looking for the center of the universe, not because of some handwave-y evasiveness, and fear of challenging the current state of affairs, but only because it makes no sense to name one.
Nobody needs to commit to finding the direction of expansion, because it is known - it's always away from the observer(neglecting the non-expansion related local movement through space).
If you would plot all the expansion vectors back to their origin point, you'd always end up finding that point in the place from which you took the expansion measurements. In other words, you could say that the center of the universe is here, or in the Andromeda galaxy, or at the edge of the observable universe, or at any given point you choose. Since it's everywhere, it can't be specifically "somewhere".
When you take that old "expanding balloon" model, it makes just as little sense to name the center of the two-dimensional space of the balloon.

[Siquo]

Everything moves away from everything else (or seems to). If not for gravity, weak and strong nuclear force, you'd fall apart as well.

[Andir]

When you take that old "expanding balloon" model, it makes just as little sense to name the center of the two-dimensional space of the balloon.

All balloons have a center.  Expanding or not.  If the universe started expanding from a finite point billions of years ago, that point should be identifiable.  Period.  If the balloon was a flat 2D plain, it has a center... that's the origin of it's expansion (aka, the center)

We were here >.< in 100 million years we are here >.<  There was movement of some type.  Correlating back from that point to a point where all galaxies resided in the same point would be the center (the beginning of that sentence.)  That's the part that nobody wants to identify.  They claim that it's impossible because of the expansion of space between us and I claim that's bunk.  Even if we are a dot in a three dimensional cube and all the dots around us are moving apart, we can correlate several dots in that cube and identify what point the majority of them are moving away from.  They will be moving away from the center at a different rate than they are moving away from us.  There's no other way I can explain my position.

Here... draw a Cartesian coordinate on paper.  Put eight dots all around the origin with a ninth dot being the origin.  (should be {0,0}{0,1}{1,1}{1,0}{1,-1}... etc.) now put 16 dots around that ({0,2}{1,2}{2,2}{2,1}... etc.)  If we are at point {1,1} and each and every dot moved away from each other at the same amount, the visible distance between {-2,1} and {-2,-1} would be further apart from our point of view.  The distance between {2,1} and {2,2} would be smaller than that amount.  We would also notice a difference in redshift from our point {1,1} and {2,2} than we would from {-2,-2} because... if all points were moving apart from each other, the distance would be three times as much between those points and the shift should be much greater.  If you correlate a set of points all around us, you should be able to determine if we are on an edge, near the origin and/or where the origin is.

It's literally impossible to have something that's expanding and not have a point of origin for said expansion unless of course you do the hand-waviness (that you like to mock me for bringing up) and claim that the universe has always looked the way it does now except for the space between galaxies (which is stretchy!)  Somehow they broke free of each other then, but cannot now and we have images of collisions of galaxies in every quadrant of space around us.

It's not "ignorance" (per say) from my part.  I've asked the questions and I keep getting the excuses and the hand-waving.  They keep saying we started at a finite point and nobody has made any attempt to identify it.

[Siquo]

Palazzo meant the surface of the balloon. According to the balloon-analogy the actual center of the universe lies within a 4th dimension. Draw dots on the balloon. Those are stars. Now inflate the balloon. Are the stars themselves actually moving? Not even, the ink does not move. Is there a "center star"? Nope. Are they moving apart? Definitely.

If you're really worried about ignorance versus hand-waving, read the official story: http://en.wikipedia.org/wiki/Metric_expansion_of_space

[Andir]

Palazzo meant the surface of the balloon. According to the balloon-analogy the actual center of the universe lies within a 4th dimension. Draw dots on the balloon. Those are stars. Now inflate the balloon. Are the stars themselves actually moving? Not even, the ink does not move. Is there a "center star"? Nope. Are they moving apart? Definitely.

If you're really worried about ignorance versus hand-waving, read the official story: http://en.wikipedia.org/wiki/Metric_expansion_of_space

I've already read that... I read the other link someone put up a while back and I read a stupid link about raisins in a ball of dough.  Even in the expanding balloon surface scenario we would see a difference in distance from near and far systems.  That difference would tell us where the balloon is expanding from.

Edit: let me put it this way.  If you have a a bunch of balloons in a big flexible box and all of them are expanding let's call these balloons the space around galaxies and the expanding balloons all push away from each other (as they would.)  If you look to the other side of that flexible box and measure the difference between two balloons at different times, then look to your side of the box and measure the distance it will be different because your balloon is pushing those around it, and those are push the ones around them... it's exponential and measurable.  (Well, they claim it's not measureable...)

[Phmcw]

No, no, no, for the expanding balloon methaphor, you live in a 2D world on the envelope of the balloon. You can't do 3D measurement.

[Andir]

No, no, no, for the expanding balloon methaphor, you live in a 2D world on the envelope of the balloon. You can't do 3D measurement.

But you can do 2D measurement... distant galaxies will move further apart than near.

[Siquo]

No, no, no, for the expanding balloon methaphor, you live in a 2D world on the envelope of the balloon. You can't do 3D measurement.

But you can do 2D measurement... distant galaxies will move further apart than near.

And that's exactly what they're doing. As with the balloon: equally in all directions.

[Andir]

No, no, no, for the expanding balloon methaphor, you live in a 2D world on the envelope of the balloon. You can't do 3D measurement.

But you can do 2D measurement... distant galaxies will move further apart than near.

And that's exactly what they're doing. As with the balloon: equally in all directions.

But nobody can take that data and determine, based on differences in movement, what direction the majority are heading and tangent from that a guess to where they all came from?

[Bauglir]

No, no, no, for the expanding balloon methaphor, you live in a 2D world on the envelope of the balloon. You can't do 3D measurement.

But you can do 2D measurement... distant galaxies will move further apart than near.

And that's exactly what they're doing. As with the balloon: equally in all directions.

But nobody can take that data and determine, based on differences in movement, what direction the majority are heading and tangent from that a guess to where they all came from?

Where they came from doesn't exist within the universe we can perceive. Their velocities are all perpendicular to said universe. That's the problem. Point at something "above" you in a 4th spatial dimension. Also, put that shit on Youtube if you pull it off, I'm sure somebody would love to see it.

[Phmcw]

But nobody can take that data and determine, based on differences in movement, what direction the majority are heading and tangent from that a guess to where they all came from?

Ok, I understand your concern. Actually they don't move by themselves, it's space that is getting bigger.

[Siquo]

But nobody can take that data and determine, based on differences in movement, what direction the majority are heading and tangent from that a guess to where they all came from?

It will always show they're all "moving" away from us, at speeds proportional to their distance, equally in all directions, so to get back on topic, in that aspect the bible might be right calling the earth the center of the universe

[Andir]

But nobody can take that data and determine, based on differences in movement, what direction the majority are heading and tangent from that a guess to where they all came from?

Ok, I understand your concern. Actually they don't move by themselves, it's space that is getting bigger.

Yeah, and now back to the circular thought that I mentioned before on how some people say it's not possible to measure because the space between expanding causes light passing through it to shift and this is where the original argument came from.  (convenienthandwave)It's impossible to measure!(/convenienthandwave)

[Il Palazzo]

Here... draw a Cartesian coordinate on paper.  Put eight dots all around the origin with a ninth dot being the origin.  (should be {0,0}{0,1}{1,1}{1,0}{1,-1}... etc.) now put 16 dots around that ({0,2}{1,2}{2,2}{2,1}... etc.)  If we are at point {1,1} and each and every dot moved away from each other at the same amount, the visible distance between {-2,1} and {-2,-1} would be further apart from our point of view.  The distance between {2,1} and {2,2} would be smaller than that amount. 

First of all, if you're an observer at point {1,1}, measuring the angular separation between objects on the sky(i.e. how far apart are e.g.{-2,1} and {-2,-1}), then it remains constant when you increase all the distances between points by an equal factor(for example, multiplying all coordinates by 2 does that). Also, the angular separation would be equal to that between points {2,1} and {2,2}, which is in both cases 45 arc degrees(π/4 radians).
As you can see, there's no point in measuring the tangential velocity of galaxies, if you're trying to find out about the expansion of the universe. All that you'll find is relatively small movements due to the gravitational attractions of each body's close neighbourhood.

We would also notice a difference in redshift from our point {1,1} and {2,2} than we would from {-2,-2} because... if all points were moving apart from each other, the distance would be three times as much between those points and the shift should be much greater.  If you correlate a set of points all around us, you should be able to determine if we are on an edge, near the origin and/or where the origin is.

See, I've got this strange feeling that one of us misses the other's point completely, as we both use the same argument to both attack and defend the theory in question.
So, yes, that's true, it's exactly what we see - the farther away is a galaxy from ourselves, the higher is it's redshift. Just as it's expected from the universe that is expanding in all directions. Now, if you'd look at all those redshifts, you'd inevitably notice that all points are moving away from you, which would suggest that you're at the center of the universe, according to your line of thought(as far as I understand). Choosing any one of the infinitely numerous points in the universe as your vantage point, and using the same line of reasoning as before, you must come to the conclusion that there are infinitely many centers of the universe.

Does this make any more sense now?

ninja pseudoedit:

But nobody can take that data and determine, based on differences in movement, what direction the majority are heading and tangent from that a guess to where they all came from?

Ok, I understand your concern. Actually they don't move by themselves, it's space that is getting bigger.

Yeah, and now back to the circular thought that I mentioned before on how some people say it's not possible to measure because the space between expanding causes light passing through it to shift and this is where the original argument came from.  (convenienthandwave)It's impossible to measure!(/convenienthandwave)

But what are you talking about? What do you want to measure? The distance between galaxies? It is measurable, indirectly of course, by comparing their velocities(redshift) with the Hubble's constant(D=V/H).