Does space move? What is space?

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In summary, the concept of space "bending" or "expanding" is a subject of debate. According to mathematical equations, space-time is simply a framework for events to occur and does not have its own movement. However, the idea that space can bend is supported by the fact that geodesics near large bodies are not straight in the Euclidean sense. Additionally, the term "expansion" is used to describe the increasing distance between objects in space. This can be further explored by researching "metric expansion." While some argue that objects are simply moving away from each other through space, this does not align with observations, particularly in regards to redshifts of distant objects. The idea that space itself is moving is not consistent with
  • #1
k9b4
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Does space move? What is space?
 
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Whether or not it is appropriate to say that space "bends / expands / curves" and so forth is a somewhat contentious issue. Basically, the math says that space-time is a framework in which things happen and does not itself matter. It "bends" in that geodesics near large bodies are not straight in the Euclidian sense. It "expands" in the sense that things get farther apart. Google "metric expansion" for further discussion.
 
  • #3
phinds said:
It "expands" in the sense that things get farther apart.
Can't we just say that the objects are moving away from each other, through space, and the space itself is not moving?
 
  • #4
k9b4 said:
Can't we just say that the objects are moving away from each other, through space, and the space itself is not moving?
For objects far away, this is not consistent with observations.
 
  • #5
mfb said:
For objects far away, this is not consistent with observations.
But hang on, what do you mean it's not consistent with observations? How can you observe space moving? You can only observe relative motion, as dalespam pointed out in my other thread in this subforum.
 
  • #6
k9b4 said:
But hang on, what do you mean it's not consistent with observations?
In the same way the hypothesis "there is no sun" is not consistent, just with more math involved.
How can you observe space moving? You can only observe relative motion, as dalespam pointed out in my other thread in this subforum.
Right, but there is no model that can reproduce the observed redshifts with objects moving in space.
 

FAQ: Does space move? What is space?

Does space move?

This is a common question and the answer is not straightforward. Space itself does not move in a traditional sense, as it is not a physical object that can be displaced. However, the objects within space, such as planets, stars, and galaxies, are constantly in motion due to the forces of gravity and other factors.

What is space?

Space is often described as the three-dimensional area in which all matter and energy exist. It is also referred to as the universe, which encompasses all of the known and unknown objects, including planets, stars, galaxies, and other celestial bodies.

Is space infinite?

The current scientific consensus is that the observable universe is infinite, but this does not necessarily mean that space itself is infinite. It is still a topic of debate and research in the scientific community.

How is space measured?

Space is measured in units of distance, such as meters, kilometers, light-years, and astronomical units. These units are used to describe the vast distances between objects in space.

Can space expand?

Yes, space can expand. This is known as the theory of the expanding universe, which suggests that the universe is constantly growing and stretching. This expansion is thought to be caused by dark energy, a mysterious force that counteracts the effects of gravity.

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