Why Does Matter Fall to Center of a Mass? Explained

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Discussion Overview

The discussion revolves around the question of why matter falls towards the center of mass in the context of General Relativity (GR). Participants explore the implications of spacetime curvature and its effects on the motion of matter, addressing both theoretical and conceptual aspects.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant questions why matter falls equally towards the center of mass regardless of its spatial position, suggesting a possible connection to the four-dimensional nature of spacetime.
  • Another participant clarifies that the curvature of spacetime is spherically symmetric near Earth, which means that the gravitational effect is uniform in all directions around the mass.
  • A different participant emphasizes that graphical representations of spacetime are inherently limited and should not be taken as accurate depictions of the four-dimensional reality.
  • It is proposed that matter does not fall "down" towards curvature but rather follows paths dictated by the curvature, which leads to falling towards the center of mass.

Areas of Agreement / Disagreement

Participants express differing views on the representation of spacetime and the nature of gravitational paths, indicating that the discussion remains unresolved with multiple perspectives presented.

Contextual Notes

Limitations include the challenges of accurately depicting four-dimensional spacetime in two-dimensional formats, which may lead to misunderstandings about gravitational effects and curvature.

Tomer Aman
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TL;DR
Why does all mater fall into the center of the mass and not down towards the curveture that the mass creates in spacetime?
Hi Guys.
I have a question about General Relativity.
If, according to GR, Mass curves Spacetime and gravity is simply matter falling into that curveture, why does all matter fall equally regardless to their spatial position on the mass. For example, why do people in let's say Australia fall into the center of the earth, and not down towards the curveture that Earth creates in 4d spacetime? Does it have something to do with the fact that its 4d and not 3d as the pictures show? Thanks
 
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:welcome:

What pictures are you looking at?

The "curvature" of spacetime is indeed in 4D, including "curvature" of the time dimension.

The important point is that the curvature near the Earth is spherically symmetric - so all around the Earth it looks the same.

And, the effect of the curvature is that the natural path for an object tends to be towards the centre of the Earth.
 
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Tomer Aman said:
Does it have something to do with the fact that its 4d and not 3d as the pictures show?
It's not really possible to accurately show spacetime on a 2D piece of paper so you won't see ANY graphic representations that are actually correct. They are heuristics for discussions with beginners / lay people and are not to be taken seriously.
 
Tomer Aman said:
Summary:: Why does all mater fall into the center of the mass and not down towards the curveture that the mass creates in spacetime?
Matter doesn't fall down towards the curvature. Instead spacetime curvature tells matter which path it falls and that is towards the center of mass.
 
Tomer Aman said:
Does it have something to do with the fact that its 4d and not 3d as the pictures show?
The pictures you probably refer to are just showing 2d curved space and no time. This might help:

 
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