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0 pointshwillis9y ago0 comments

If it can accelerate forever, thats proof enough for everyone. However violating the conservation of momentum is a Big Deal. Mathematically that shouldn't be possible due to Noether's. The bar to proof is therefore very high.

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naasking9y ago

General relativity doesn't conserve energy in some spacetimes, so it's not unheard of.

andrewflnr9y ago

I'm fairly certain GR conserves momentum, even if it doesn't conserve energy.

naasking9y ago

I thought so too until recently, but in GR energy and momentum are unified in an energy-momentum metric which is only locally conserved [1].

[1] https://en.wikipedia.org/wiki/Physical_theories_modified_by_...

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naasking9y ago

General relativity doesn't conserve energy in some spacetimes, so it's not unheard of.

andrewflnr9y ago

I'm fairly certain GR conserves momentum, even if it doesn't conserve energy.

naasking9y ago

I thought so too until recently, but in GR energy and momentum are unified in an energy-momentum metric which is only locally conserved [1].

[1] https://en.wikipedia.org/wiki/Physical_theories_modified_by_...

j / k navigate · click thread line to collapse