Is Expansion Motion and Does It Imply Space as Something?

  • Context: Graduate 
  • Thread starter Thread starter girlwonder
  • Start date Start date
  • Tags Tags
    Expansion Motion
Click For Summary

Discussion Overview

The discussion revolves around the nature of expansion in the context of space and motion. Participants explore whether expansion can be considered a form of motion, the implications of treating space as "something," and the relationship between mass, coordinates, and energy during expansion. The conversation touches on theoretical and conceptual aspects of physics.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants suggest that if expansion is motion, then space must be considered "something," which raises questions about ether theories.
  • Others argue that expansion is not motion, prompting requests for clarification on this viewpoint.
  • One participant explains that expanding a mass involves changing the coordinates of its points, similar to moving the mass itself, and associates expansion with energy consumption.
  • Another participant contends that the movement observed in an expanding loaf of bread is due to the grains moving apart, questioning the meaning of "nothingness" having velocity.
  • There is a perspective that space-time is a form of "something," and that our universe can be viewed as a one-dimensional duration that expands, filled with motion.
  • One participant expresses uncertainty about which type of space is being discussed, suggesting that if it is the space between particles, it may not be expanding but rather being filled by substitutes.

Areas of Agreement / Disagreement

Participants express differing views on whether expansion constitutes motion, with no consensus reached. Some argue for the idea that space is "something," while others challenge this notion.

Contextual Notes

The discussion includes various assumptions about the nature of space, motion, and the definitions of expansion, which remain unresolved. The relationship between energy and expansion is also a point of contention.

girlwonder
Messages
27
Reaction score
0
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?
 
Physics news on Phys.org
Expansion isn't motion.
 
Could you explain why please, that's where I'm lost i guess.
 
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?
 
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.
 
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.
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.
 
Thanx a bunch.
 
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
 

Similar threads

Undergrad Reference frames in terms of homogenity/isotropy
  • · Replies 18 ·
Replies
18
Views
2K
Undergrad Is the expansion of the universe affecting time or just space?
  • · Replies 22 ·
Replies
22
Views
3K
Undergrad How Does Friction Function in the Movement and Turning of a Car?
  • · Replies 45 ·
2
Replies
45
Views
5K
Graduate Regular vs stable orbits in spherically symmetric potentials
  • · Replies 4 ·
Replies
4
Views
1K
Why can’t we observe all regions of the universe?
  • · Replies 3 ·
Replies
3
Views
1K
Undergrad Using reference frames for derivation of Lagrangian
  • · Replies 25 ·
Replies
25
Views
3K
High School Can the "creation" of space in the Universe affect the speed of light?
  • · Replies 7 ·
Replies
7
Views
4K
Graduate Movement vs expansion in space
  • · Replies 49 ·
2
Replies
49
Views
3K
High School Expansion of Space Itself, rather than due to an Explosion like the Big Bang?
  • · Replies 9 ·
Replies
9
Views
3K
High School How does mechanical motion start at the deepest, smallest level?
  • · Replies 36 ·
2
Replies
36
Views
5K