What Gravity Is Within A Shell Of Matter?

Rev. Green | 09:19 Mon 15th May 2023 | Science

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It is straightforward to show, using the inverse-square law, that a uniform shell of matter produces no gravitational force in the space within it. However, the inverse-square law assumes Newtonian mechanics. If we consider Einsteinian mechanics, is there a small gravitational force within the shell, and is it directed towards the shell i.e. away from the centre?

My Last Gcse Math Question - Ever!!

Neutrino

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ClareTG0ld

Sort of. Space remains flat, but some care is needed when dealing with the timelike coordinate. This isn't a problem in Newtonian mechanics, because that doesn't care about time, but becomes more subtle in GR, and you need to modify things slightly there.

https://arxiv.org/pdf/1203.4428.pdf

Rev. Green

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Thank you, I was not aware of this paper, and I don't fully understand it. Are they saying that the space inside an empty shell is flat (no gravity) according to NM; most people also thought it flat according to EM; but they will consider it flat according to EM only if time is discontinuous at the border?
If so, that is disappointing.

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