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[Andir]

I never said anything about constant velocity.  I never disputed acceleration.  I'm saying that the yellow galaxy in that image should be moving away from us faster than the blue.  If we could find a galaxy that we think is between the blue and the orange it should not be moving away from us as much as the yellow and it will not be moving away from us as fast as the blue or orange... that would be a vector of origin... a point we are expanding into, have expanded from or a point that is expanding parallel to us.

I have no idea what you are talking about with people and balls Il Palazzo

If there's no point of origin, the big bang is false... I feel like I'm talking in circles here...   If the whole universe was at one point smaller and we are expanding, there is a point where we were before and we are expanding into another point where we will be.  That movement denotes an origin point where we were.... you collect enough data and you should be able to find a direction for which the universe is expanding from because we are being pushed away form galaxies that are being pushed away from other galaxies... the longer this goes, the more of a picture we get.

There are a few expansion concepts, some of which are just examples, but I'm putting them out here...

1.  If we are only a small dot on a round plain of expansion (I'm not talking about 4 dimension, just three) like our galaxy was some human on the face of an expanding Earth and all humans are galaxies...  we should be able to look at all the humans and see we are all moving away from some point and point toward the center of Earth and say it started there.  (This is not what I imagine the big bang is saying... just an example)

2.  If the universe is homogenous and all galaxies are expanding away from each other consistently and unmoving the "corners" of some imaginary box would be moving away from us faster than the faces.  The "core" of the universe or the center or the origin or the beginning of expansion or whatever you want to call it would be at the point of least expansion because these would not be pushed as much as those on the edges.  The galaxies would remain in the same parts of the sky but get further away.  This is what I imagine the big bang is saying.  This is what I'm trying to "prove" by measuring the differences in red shift.

3.  There is a man pushing expanding marbles up into a cone where the marbles simply find room to fill and they move all over the sky because they are looking for space to expand into.  This would mean that there is still a general direction of travel (toward the big part of the cone) but there would be galaxies pushing away from each other trying to find some space to fill.

4.  Every galaxy is expanding away from each other at the same rate.  This would cause some galaxies to have to adjust so they don't expand into other galaxies and they would move in the sky to show that movement.  It would be like blowing bubbles in water... the bubbles would all flow out from the center point where you are blowing the bubbles, but they would flop into empty spaces like the cone example above trying to keep as close to the center point as possible.  (Again, not what I think the big bang is.)

And now the conversation is back to the idea that we are not moving again... take the dough example... the dough is expanding, but at one point that now baked bread is bigger than the dough ball it started as.  That movement of raisins is measurable.

[ECrownofFire]

If you don't think that's what the big bang is saying, then why bother with those at all?

Disregarding gravity, two points that are the same distance from us are always going to move at the same expansion rate. This experiment was done with the Hubble telescope. There are no differences in the redshift except from gravity itself.

There was no origin point. You are misinterpreting the Big Bang. There is really no example you could use for this except for the universe itself...

[Il Palazzo]

You didn't like the joke with your balls being the center of the universe? Duh.

As much as it's hated by all, let me break it down:

I never said anything about constant velocity.  I never disputed acceleration.  I'm saying that the yellow galaxy in that image should be moving away from us faster than the blue.  If we could find a galaxy that we think is between the blue and the orange it should not be moving away from us as much as the yellow and it will not be moving away from us as fast as the blue or orange... that would be a vector of origin... a point we are expanding into, have expanded from or a point that is expanding parallel to us.

We can measure this. As it was said many times before. All the distant galaxies are receeding away from our vantage point on Earth. There is no other component. We are the origin of the expansion.

If there's no point of origin, the big bang is false... I feel like I'm talking in circles here...   If the whole universe was at one point smaller and we are expanding, there is a point where we were before and we are expanding into another point where we will be.  That movement denotes an origin point where we were.... you collect enough data and you should be able to find a direction for which the universe is expanding from because we are being pushed away form galaxies that are being pushed away from other galaxies... the longer this goes, the more of a picture we get.

The BB requires there being no point of origin. Therefore, if there isn't one, then it's something that validates the theory, not disproves it.

1.  If we are only a small dot on a round plain of expansion (I'm not talking about 4 dimension, just three) like our galaxy was some human on the face of an expanding Earth and all humans are galaxies...  we should be able to look at all the humans and see we are all moving away from some point and point toward the center of Earth and say it started there.  (This is not what I imagine the big bang is saying... just an example)

This is a bad example, because you're thinking of a third dimension while analysing an essentially two dimensional space(surface of the earth). If you'd place yourself in a position of being able only to perceive the surface itself, then you wouldn't be able to name any single point on that surface as being the origin of the expansion.

2.  If the universe is homogenous and all galaxies are expanding away from each other consistently and unmoving the "corners" of some imaginary box would be moving away from us faster than the faces.  The "core" of the universe or the center or the origin or the beginning of expansion or whatever you want to call it would be at the point of least expansion because these would not be pushed as much as those on the edges.  The galaxies would remain in the same parts of the sky but get further away.  This is what I imagine the big bang is saying.  This is what I'm trying to "prove" by measuring the differences in red shift.

That's true. The corners of any arbitrary cube of space are moving away faster(from the point in the middle)than the rest of it. What it appears to be showing, is that the central point of the cube is the origin of the expansion. But if you'll switch your observation point(move the cube) so that the once-corner is now at the center, the redshift measurements will still show that the center of the universe is at the center of the new cube. Does it mean that there are two centers then? In a way, yes. There are as many centers of the universe as there are points in space, which is just as meaningful as saying that there is no single center of the universe.

I don't get 3, I'm afraid.

4.  Every galaxy is expanding away from each other at the same rate.  This would cause some galaxies to have to adjust so they don't expand into other galaxies and they would move in the sky to show that movement.  It would be like blowing bubbles in water... the bubbles would all flow out from the center point where you are blowing the bubbles, but they would flop into empty spaces like the cone example above trying to keep as close to the center point as possible.  (Again, not what I think the big bang is.)

The rate of expansion is constant in the sense that there is a constant factor by which each "bit" of space stretches. If there is more space in between any two objects than between some others, then the first pair receeds faster from each other than the second(more space is created).
There is no need for any adjustments. The space between any two galaxies is expanding, so if anything, they are all receeding from each other, no matter which galaxies you look at.

And now the conversation is back to the idea that we are not moving again... take the dough example... the dough is expanding, but at one point that now baked bread is bigger than the dough ball it started as.  That movement of raisins is measurable.

But if the dough is infinitely large, then there are infinitely many points that you could point to and call the center. Makes no sense.


Look, try thinking of BB in this way:
All the universe, all the matter and space, both possibly infinite, existed since the begining. The only thing that changed was the density of the universe - the amount of matter per unit of space(e.g. kg/m3 or hydrogen atom per light year cubed) was higher before than it is now. Still, the universe was just as "large" - that is, you could go in any one direction and never reach the end of it.
What the BB postulates, is that the density begun to fall rapidly, as the space begun to inflate, creating the effects that we can observe now - the redshifts and bacground radiation.

[Andir]

Right, so if the "corners" of that box are moving faster... we agree then?

Now, define "corners" in our visible space.

We should find that one corner is moving away from us faster than the others.  This is because we are expanding away from the origin, but the corner is expanding away from us at a rate of our expansion from origin plus it's expansion from us.  Got it?

Imagine a Rubics (Rubiks?) Cube and we are in one of the corner cubes.  If all the cubes are expanding and we look at the outside corner of our cube and it's moving away. from us faster than the inside corner, we know that the inside corner is the point we came from.  We do not know which of these corners is the outside, but if we examine them all, we can come up with a ratio to determine our vector of expansion.

If you say that all galaxies are expanding away from us at the same rate, then we would be pushing our inner corner galaxies into the center.  This would cause collisions with all the other cube's galaxies.  So we get pushed further out and we push the galaxies further away from us on that outside corner.  Because we can't push the galaxies into the center because that would be bad, we are being pushed out and so on... causing an increase in expansion distances the further you get from the origin of the expansion.

[Shades]

Imagine it as a sphere not a cube, and image that the visible 3d space you can see is the surface of that sphere. Now expand the sphere so everything is getting further apart and you probably have a better view of it than your trying with the cube.

[ECrownofFire]

You still don't get how the expansion works. The galaxies are not "moving". They are staying in exactly the same position they were billions of years ago, not accounting for gravity. They are only moving relative to us. What's happening in the universe is that the space in between the galaxies is expanding. You are not pushing the galaxies into the "center" because everything is "moving" in the same direction (away from us). What makes you think that something moving away from us slower than something else defines the first object as where we came from? All it means is that there is less space between it and us, per the expanding space. According to your theory, we would've had to come from the center of the cube, which is impossible, because the closer corner is moving towards it.

[malimbar04]

Rubik's (the inventor's last name is Rubik, ant it's his cube)

We're tossing around analogies all over the place, let's try to keep to one. I'll use the Rubik's cube since that's the most recent one.

Pretend that your Rubik's cube is expanding. Why? because it's magical. It just continuously gets bigger. Where is the origin of the of the cube parts? They all are moving at a vector away from the center is one thing you could say. Alternatively, they are all moving away from each other. It doesn't really matter as to the origin of the expansion.

Imagine the stickers to be non-magical. Thus while the cube expands, the stickers do not expand, but still stay stuck to, say, the center of their sticker spots. That's what we see.

[Il Palazzo]

Right, so if the "corners" of that box are moving faster... we agree then?

Now, define "corners" in our visible space.

We should find that one corner is moving away from us faster than the others.  This is because we are expanding away from the origin, but the corner is expanding away from us at a rate of our expansion from origin plus it's expansion from us.  Got it?

I didn't realise you were trying to contradict the observational data.
If we were indeed moving through space, away from the point of origin, as if we and all our neighbours were shot out in a giant explosion of matter, then we would indeed find out that some objects are moving away faster than the others, despite being at the same distance.
But since the observations prove beyond reasonable doubt that regardless of the direction you'll look at, every object moves away from us at exactly the same speed as any other equidistant object, and that there exist a constant factor that relates the distance and velocity(Hubble's Law - V=Hd), the model you're talking about does not fit the observations at all.
However, if you'll assume that the space itself is stretching, then the predictions of such a theory begin to fit the observations.
And that's exactly what the BB is about. It's not a theory that somebody made up out of the blue, and then refused to look at the holes in it, as you seem to suggest. It's the only theory so far that is consistent with the observations.

Imagine a Rubics (Rubiks?) Cube and we are in one of the corner cubes.  If all the cubes are expanding and we look at the outside corner of our cube and it's moving away. from us faster than the inside corner, we know that the inside corner is the point we came from.  We do not know which of these corners is the outside, but if we examine them all, we can come up with a ratio to determine our vector of expansion.

If you say that all galaxies are expanding away from us at the same rate, then we would be pushing our inner corner galaxies into the center.  This would cause collisions with all the other cube's galaxies.  So we get pushed further out and we push the galaxies further away from us on that outside corner.  Because we can't push the galaxies into the center because that would be bad, we are being pushed out and so on... causing an increase in expansion distances the further you get from the origin of the expansion.

We would not be pushing at anything. You, for some reason, refuse apply the principle of stretching space to ALL of it. For the galaxies to collide with the farther ones, there would have to be no expansion of space between the two objects that you're assuming will collide.

[Bauglir]

The origin point of the universe can't be determined from within the universe for the same reason that you can't physically point at your own conception. If the 3-dimensional universe is equivalent to the 2-dimensional surface of the balloon, a 4th dimension is equivalent to the 3rd dimension necessary to point at the center of said balloon.

[Dr_Pylons]

I normally wouldn't comment on something like this, but this is just something that helped me overcome my need to bash either side, "atheist" (which could technically still be Buddhist, Jain, Taoist, etc.) or any theistic philosophy or religion.
I'm sure at least some of you have heard of Joseph Campbell. If you haven't, I suggest you read or watch The Power of Myth with Bill Moyers. It's a great read/watch, and helps to "unliteralize" the word in the books; seeing the metaphors helped me deal with any uncertainties I had about myself and spirituality, and helped me develop into a more well-rounded person. If nothing else, give it a try. It might help you out as it helped me out to understand myself, and really made me feel better about the universe. I know it sounds Oprah-y, but don't be afraid, it's not some new-age thing. It's as old as the universe, you could say . And, if it doesn't, no worries-- there are many ways to understand what man's place in the universe is. I just found my way to do so, and I'm a happier person because of it.

[Andir]

Imagine it as a sphere not a cube, and image that the visible 3d space you can see is the surface of that sphere. Now expand the sphere so everything is getting further apart and you probably have a better view of it than your trying with the cube.

You can't have everything moving at the same speed away from every single point.  If you did that, it would appear to be moving differently from other points.  The fact of geometry if that the hypotenuse will "stretch" more than the adjacent and opposite sides of a triangle.  This would mean that the galaxy at the hypotenuse point (opposite you) of any expansion will move further away from you than the point at the end of the adjacent line (opposite you.)  If it stretches the same distance as the adjacent side and from the observation point of the adjacent point it will appear to have not moved as far.  I consider the idea that all galaxies move apart at the same distance over the same period of time radial expansion. (ie: the distance between the origin and every radius of the sphere moves apart the same distance...)  This would never work in the big bang, everything is moving away from everything else, universe unless you were in the center of a big explosion and you were watching things fly away from you consistently and then you'd end up with a big empty space and a huge sphere of galaxies far off in the distance... that's the Earth example I had earlier.  If you were observing this type of expansion from a point in that sphere you'd notice everything flying off in one direction, away form the center of the sphere...

What I'm talking about is Cubic expansion (ie: where the adjacent and opposite sides are expanding at some value making the hypotenuse value expand at a much greater distance over time.)  Cubic expansion is the only explanation that would keep all the galaxies in the relative same spot in our sky... and for that to happen, you have to have the corners of the cube expanding away from you faster than the faces.

If observational data says that all objects are moving away from us at the exact same speed all over the sky then it's messed up because if you relocated to one of the galaxies far off and looked at us, you'd see the galaxies moving horizontally across the sky away from us... even if they were moving away from that galaxy that we relocated to we'd see them moving away from that one.  There would be horizontal movement in the sky and that doesn't make sense while also saying that none of the stars move apart from any relative position.

[ECrownofFire]

Observational data is NOT saying that it's the same speed. Given the same distance, then yes, but not every single object out there.

I don't know what you're trying to say about "cubic" vs "radial", but it better not have anything to do with Time Cube

[Phmcw]

Meh, what is happening is impossible to visualise. Thing don't move away at the same speed, they are moving away from each oher at a speed depending for the distance between them. If they are on light year away, they move at speed X from each other. If it's two ligh year, it's speed two x. Always radially.

[Bauglir]

The sphere isn't expanding in 3 dimensions. It's not that things are moving outward in a shell, as they would from an explosion. The Big Bang wasn't an explosion of matter into space. Space, itself, expanded from a point. To reuse the analogy again, if your only concept of movement is in 2 dimensions, then of course there is only one possible line that can form a given angle with a given line. Given a third, however, you can rotate about that first line, giving an infinity of options. The point is that the assumptions you're making are flawed; the universe's expansion is not in any of the 3 dimensions we can directly measure.

[Il Palazzo]

Andir, this is where you are wrong in your line of reasoning:
You're mixing up the 2D model of an expanding sphere and the 3D space that it's supposed to represent.

What you call "cubic" expansion is what we call "radial" expansion(radius is just the name of the position vector running between any two points. It does not necessarily imply a rigid surface of a sphere. What you call "radial" expansion is your misinterpretation of the expanding balloon model(you can't think in 3D there!).

Moving away at the same speed as the equally distant object does not mean that everything is moving away at the same speed.


But let's start from the begining:
We observed something about the universe - the farther an object is, the faster it is moving away from us. Since the observations show that the relationship between distance and velocity is linear, we can write an equation: V=Hd, where V is the relative velocity between us and the object, d is the distance between us, and H is some constant than determines how much faster are the distant objects moving away than the closer ones.
Also, there appears to be just as many galaxies in one direction as there is in any other.
Now, what can you deduce from this data?

edit: oh, right, and as people said earlier - the universe is expanding with the constant acceleration. When we talk about different objects moving at certain speeds, it does not imply that those speeds are constant - we are only perceiving their certain values at this particular moment in time.