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> I don't understand what you mean by conservation of gravity. Do you mean conservation of mass? I don't. Say you suddenly open a wormhole and gravitational fo

by ars 8y ago

> I don't understand what you mean by conservation of gravity. Do you mean conservation of mass? I don't. Say you suddenly open a wormhole and gravitational force pours though. This would violate conservation of gravity since now there is gravity when before there wasn't. i.e. such a wormhole would be impossible. Or some kind of gravity shield that blocks any gravity from passing. Again, violates this rule. (It would have to deflect the gravity instead, so the total force doesn't change.) > there's nothing in any of our physical theories that says you cannot have magnetic monopoles It's not about having the monopole, it's about creating just one of them, and not creating both at once. I believe there is a conservation of magnetism law that would prevent that, analogous to conservation of charge (you can not create just one charge, both a plus and minus need to be created together).

semi-extrinsic 8y ago
> Say you suddenly open a wormhole and gravitational force pours though. This would violate conservation of gravity since now there is gravity when before there wasn't. Note that you can replace "open a wormhole" by "suddenly introduce a mass" and this statement is the same. In practice, both "introducing a mass" and "opening a wormhole" cannot be done instantly unless you violate conservation of energy, and as Einstein told us, energy also introduces gravitational force. So as you're turning the wormhole on, you would see the gravitational field increasing slowly and in accordance with conservation of mass and energy. There's no additional "conservation of gravity". > It's not about having the monopole, it's about creating just one of them, and not creating both at once. Ah, but this is conservation of magnetic charge. In a world where magnetic monopoles exist, this follows directly from the "full" Maxwell's equations, just like electric charge conservation does. See https://en.wikipedia.org/wiki/Maxwell's_equations#Charge_conservation https://en.wikipedia.org/wiki/Maxwell's_equations#Charge_con... But the point is, we can't even create two magnetic monopoles in a way that conserves total magnetic charge. We literally need a new fundamental particle for this to happen.

by ars 8y ago

semi-extrinsic 8y ago

> Say you suddenly open a wormhole and gravitational force pours though. This would violate conservation of gravity since now there is gravity when before there wasn't. Note that you can replace "open a wormhole" by "suddenly introduce a mass" and this statement is the same. In practice, both "introducing a mass" and "opening a wormhole" cannot be done instantly unless you violate conservation of energy, and as Einstein told us, energy also introduces gravitational force. So as you're turning the wormhole on, you would see the gravitational field increasing slowly and in accordance with conservation of mass and energy. There's no additional "conservation of gravity". > It's not about having the monopole, it's about creating just one of them, and not creating both at once. Ah, but this is conservation of magnetic charge. In a world where magnetic monopoles exist, this follows directly from the "full" Maxwell's equations, just like electric charge conservation does. See https://en.wikipedia.org/wiki/Maxwell's_equations#Charge_conservation https://en.wikipedia.org/wiki/Maxwell's_equations#Charge_con... But the point is, we can't even create two magnetic monopoles in a way that conserves total magnetic charge. We literally need a new fundamental particle for this to happen.