Thread: Gravity, speed & mass

If a sphere of iron (or anything else for that matter) were to spin at a very fast speed (close to the speed of light), would its mass and gravitational pull on objects around it increase??

If so why??

If not... (also) why??

It will be increase according to E=mc (square)
But i am not sure whether c only represent the linear velocity of the object.

Originally Posted by BraveBen

If a sphere of iron (or anything else for that matter) were to spin at a very fast speed (close to the speed of light), would its mass and gravitational pull on objects around it increase??

If so why??

If not... (also) why??

Absolutely! The kinetic energy of rotation would contribute to the stress energy tensor which produces a curvature in space (gravity) according to Einstein's General theory of relativity. In fact I think there would be some serious frame dragging going on as in the case of a Kerr black hole. However I doubt that a spin of this magnitude would be possible for anything but a black hole or a particle, because anything else would fly apart. There just aren't any forces except the gravity of a black hole which can supply the requisite centripedal force. In the case of a particle, the idea of a tangential velocity approaching the speed of light does not apply but it is equivalent to talk about the rotational energy of the particle exceeding the mass energy of the particle, but I have never heard of such a senario discussed so I have no idea what would happen in such a case. very interesting.....

sorry if it is wrong but if any thing is spinning or moving equal to the speed of light does it not burst off.

light has nothing to do with combustion... if the atom fals apart we even have a new energy scource.. so it's still usefull to know..

my idea is that if an atom spins at high speed (as normal) it generates a low level gravity field (as an electron is a high number of negatively charged gravitons <--- a hunch) of the force grows greater the gravity increases as well..

i don't know how high we can make it before total integrety loss of the matter takes place...

So could powerful magnets be used to spin and maintain the integrity of the object being spun???

I doubt it. A magnet that powerful spining that fast would induct massive electric currents in everything around it and produce incredible radation. It would make a pulsar seem mild.

the object spinning wouldn't be the magnet

although, as i know nothing about magnetics, perhaps it would still have the same problem

Even though it is not possible to have a magnet that strong at all, a magnet powerfull enough to keep itself together when spinning that fast would either collapse into itself and destroy is own field or rip whatever is trying to spin it to shreds.