Gravity and mass in General Relativity

In summary, the level of gravity on a planet is determined by the mass, size, and spin of the planet, as well as the distribution and movement of mass and energy. Space and time curvature are affected by these factors, not just the size of a body.
  • #1
Mekon
6
0
Hello all,
If there are two planets of identical size but very different mass, why does one have a higher gravity than the other given that space/time is curved by each in the same way? Or does space/time curvature depend not on the size of a body but its mass?
TIA
Mekon
 
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  • #2
Spacetime curvature caused by a massive body depends on the body's size, mass, and spin. Curvature depends on the distribution and movement of mass/energy.
 
  • #3
Mekon said:
Hello all,
If there are two planets of identical size but very different mass, why does one have a higher gravity than the other given that space/time is curved by each in the same way? Or does space/time curvature depend not on the size of a body but its mass?
TIA
Mekon
Curvature depends upon "mass-energy". Where in the world did you get the idea that it depended on "size" (volume)?
 

1. What is the relationship between gravity and mass in General Relativity?

In General Relativity, gravity is not seen as a force between two masses, but rather as a curvature of spacetime caused by the presence of mass. The more massive an object is, the more it curves the fabric of spacetime, resulting in a stronger gravitational pull.

2. How does General Relativity explain the bending of light around massive objects?

In General Relativity, the curvature of spacetime caused by the presence of mass also affects the path of light. As light travels near a massive object, its path is bent due to the curvature of spacetime, resulting in the phenomenon known as gravitational lensing.

3. Can massless particles, like photons, be affected by gravity in General Relativity?

Yes, even though they have no mass, photons are still affected by the curvature of spacetime caused by the presence of mass. This is why light can be bent by massive objects and why gravitational lensing can occur.

4. How does General Relativity differ from Newton's theory of gravity?

In Newton's theory, gravity is seen as a force between two masses, whereas in General Relativity, gravity is seen as a curvature of spacetime caused by the presence of mass. Additionally, General Relativity takes into account the effects of high speeds and strong gravitational fields, while Newton's theory does not.

5. Can General Relativity explain the phenomenon of black holes?

Yes, General Relativity predicts the existence of black holes, which are massive objects with such strong gravitational pull that not even light can escape from their surface. The intense gravitational pull of a black hole is a result of the extreme curvature of spacetime caused by its mass.

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