Re: Gravitomagnetism

From: robert bristow-johnson (rbj_at_audioimagination.com)
Date: 10/13/04 

Date: Wed, 13 Oct 2004 08:57:02 +0000 (UTC)

in article ckh4d2$6fb$1@titan.btinternet.com, Ziggi at one_ziggi@hotmail.com
wrote on 10/12/2004 14:45:

> This is going to sound like a very bizarre and possibly insane question, but
> indulge me if you can.
>
> Ok, so I was thinking the other day: "Would it be possible to write down a
> set of differential equations for some field that, in flat space, looks
> kinda like EM, but it curved space has a gravity term/component? Sort of
> like the way a magnetic field at zero velocity looks partially electric at 0
> < v < c".
>
> I know it's a bit of an odd question, but I was curious as to how one would
> contruct such a theory and what it would look like. Answers on a postcard
> :p

i don't see it as an odd question at all. i've been thinking about it
myself for as long as i understood (as best as a "lay" physiker can - i'm an
electrical engineer so that might give you an idea of the limits of my
physics expertise) how Electromagnetic forces could be derived from
Electrostatic forces with Special Relativity taken into consideration. i
have thought "Why not do the same for gravity? They are both inverse-square
forces and have a velocity of propagation of c, so why not?" folks on this
newsgroup haven't been too impressed and that's fine with me.

Anyway, there is a name for this theory and it's called
"Gravitoelectromagnetism" (GEM) and there isn't yet a Wiki page for it yet.
This GEM theory has counterparts to Maxwell's Equations that look just like
Maxwell's Equations (and the Lorentz force equations) with "q" replaced by
"m", 1/(4*pi*epsilon0) replaced by -G (just as it is in the Coulomb force
law to get to Newton's law of gravitation) except that the magnetic flux in
GEM is expressed as "B/2" instead of "B". There are at least two papers:

http://arxiv.org/PS_cache/gr-qc/pdf/9912/9912027.pdf

http://www.iop.org/EJ3-Links/26/B2PcnrMQ9Qr,dG8lppV,HA/q01911.pdf

that derive these GEM equations from GR (Einstein's Field Eq.) for flat
spacetime.

I haven't understood the B/2 scaling thingie (they say its because gravitons
are spin-2 particles) because it seems like, at velocities of c/2, the
gravito-magnetic forces completely counteract the gravito-static force and
that should not happen (from the p.o.v. of Special Relativity) until the
velocity is close to c. at least that's how this amateur looks at it. i
wish the experts here could give me an explanation of that seeming
contradiction.
 
> ps, spare no technicality in your response... I'm not exactly a "lay" person
> :)

but i am.

r b-j

Relevant Pages

  • Re: Gravitomagnetism
    ... > set of differential equations for some field that, in flat space, looks ... but it curved space has a gravity term/component? ... > like the way a magnetic field at zero velocity looks partially electric at 0 ... physics expertise) how Electromagnetic forces could be derived from ...
    (sci.physics)
  • Re: Gravitomagnetism
    ... > set of differential equations for some field that, in flat space, looks ... but it curved space has a gravity term/component? ... > like the way a magnetic field at zero velocity looks partially electric at 0 ... physics expertise) how Electromagnetic forces could be derived from ...
    (sci.physics.research)
  • Re: The Measurement of Contraction
    ... The effects are in proportion to the velocity of the object ... If you would study physics, rather than memorizing a text and ... a fluid co-ordinate system. ... from gravity U. ...
    (sci.physics.relativity)
  • Re: Gravity slows light, why not the clocks inside 1971 plane experiment?
    ... light storage for computing tasks more than on the velocity of light ... also light (photons) perhaps it also affects their initial photon ... Present belief is that gravity slows down clocks of SAME ALTITUDE by ... then also perhaps a faster moving clock (than ...
    (sci.physics.relativity)
  • Re: Dayton Millers Data have no Real Signal
    ... >it is a function of the velocity of the electron, ... Not among the attributes of matter are gravity. ... >> can your technology produce anything I might want? ... >> to hate bugs, the Box Elder and Lady bugs have turned ...
    (sci.physics.relativity)