Curvature of spacetime inside hollow sphere

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SUMMARY

The discussion centers on the curvature of spacetime within a hollow lead sphere containing two smaller lead balls. It establishes that while the outer hollow sphere curves spacetime due to its mass, the introduction of the smaller balls alters the spacetime geometry inside the sphere. This change occurs because the distribution of matter and energy affects the geometry of spacetime, as defined by General Relativity. The concept of invariance in spacetime geometry applies to observers but does not imply uniformity across different mass distributions.

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  • Understanding of General Relativity principles
  • Familiarity with spacetime curvature concepts
  • Knowledge of mass-energy distribution effects on gravity
  • Basic grasp of invariant properties in physics
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  • Study the implications of mass distribution on spacetime geometry in General Relativity
  • Explore the concept of gravitational fields within hollow spheres
  • Investigate the role of energy-matter interactions in spacetime curvature
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This discussion is beneficial for physicists, students of theoretical physics, and anyone interested in the complexities of spacetime and gravitational theories.

Tony Stark
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If mass curves spacetime in its vicinity, then consider the following case-
Take a heavy hollow lead sphere which has 2 smaller lead balls placed in it. The Outer Sphere will curve spacetime around itself and thus will have its own gravity, but what about the 2 balls placed in it? The spacetime already have been curved by the outer sphere, then how will the two smaller balls have their own gravity?
 
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Tony Stark said:
The spacetime already have been curved by the outer sphere, then how will the two smaller balls have their own gravity?
Space time geometry inside the big shell with the smaller balls is different than without them.
 
A.T. said:
Space time geometry inside the big shell with the smaller balls is different than without them.

Outside too, of course. (A.T. already knows this, I'm just not sure that OP does).
 
A.T. said:
Space time geometry inside the big shell with the smaller balls is different than without them.
The geometry of spacetime is taken invariant in General Relativity, so how can it be different..
 
Tony Stark said:
The geometry of spacetime is taken invariant in General Relativity
Where did you get that idea from?
 
Tony Stark said:
The geometry of spacetime is taken invariant in General Relativity

"Invariant" means "the same for all observers" (or in all frames of reference). It does not mean "the same for all possible distributions of matter and energy". If you change the distribution of matter and energy (for example, by putting two smaller lead balls inside a hollow lead sphere, instead of just having the hollow lead sphere with nothing inside it), you change the geometry of spacetime.
 
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