# Expansion as motion

1. Feb 16, 2007

### girlwonder

If expansion is motion, and space is expanding, and we consider space as void, how can it then move? Don't we have to consider space as "something" if it moves? If we consider space as "something", doesn't that launch us back to ether theories?

2. Feb 16, 2007

### cesiumfrog

Expansion isn't motion.

3. Feb 16, 2007

### girlwonder

Could you explain why please, that's where i'm lost i guess.

4. Feb 17, 2007

### girlwonder

If a mass is comprised of a certain fixed number of points that are assigned co-ordinates and you expand it , the value of these co-ordinates change just like they would if you moved the whole mass over, or up or down.

Also to expand a mass generally involves energy, just like motion.

If i were to watch a loaf of bread expand i could easily say it was moving.

In what way isn't it?

5. Feb 17, 2007

### cesiumfrog

It is the grains of the loaf that are moving (away from each other).

If there is nothing between those grains, what meaning is there in saying the "nothingness" has a velocity? After all, we can only measure things.

6. Feb 18, 2007

### petm1

If there were nothing between the grains I believe the grains would be touching each other. Space-time is something. Try thinking of time as a one dimensional object. Now you can see that our universe is just a one dimensional duration, and as it expands, we with our view from the inside looking out see this over all motion as space expanding. What we call reality is made up of all the motion in all its different combinations that are confined inside this one duration we call our visible universe, and yes it is filled with space-time.

7. Feb 22, 2007

### girlwonder

Thanx a bunch.

8. Feb 22, 2007

### eaboujaoudeh

i believe that expansion is a form of motion, but what space r u talking about? if its the space between the particles its not expanding but its being filled by substitutes