Crown-Horned Snorkack wrote:
> Newton equations for gravity look like Coulomb equations for
> electrostatic forces. Both are forces whose strength decreases with
> inverse square distance, because the divergence of the field is
> pro****tional to the density of mass and charge respectively.
>
> The one difference is that like masses attract while like charges
> repel.
>
> It turns out that there is also a gravitomagnetic field - a field with
> curl rather than divergence, which will exert a Lorenz force on moving
> masses perpendicular to the direction of movement.
>
> Gravitomagnetic field is generated by moving masses as well as by the
> displacement current of changing gravitoelectric fields.
>
> And while stationary gravitomagnetic field force only affects moving
> masses, changing gravitomagnetic field will induce curl of
> gravitoelectric field!
>
> This ability of changing gravitomagnetic and gravitoelectric fields to
> induce curls to one another is what enables gravity to travel as
> gravitational waves.
>
> However, the existence of gravitomagnetic fields raises the question
> of how a gravitomagnetic monopole ought to behave...
Oh, I see what you're asking.
Well, there's an obvious problem here. In Newtonian mechanics, there
are no gravitomagnetic effects, and so the notion of a "gravitomagnetic
monopole" is a non-starter; it just doesn't make any sense.
There are gravitomagnetic effects in general relativity, but there
aren't even really "gravitoelectric monopoles" there. The generator of
spacetime curvature, and thus gravity, isn't just just mass, but
stress-energy, which is a tensor of which mass is but one component, the
others being energy, stress, pressure, and so on. Indeed, many
applications of general relativity don't even deal with individual
massive particles ("gravitoelectric charges"), but rather continuous
fluids.
One could, I suppose, view gravitomagnetic effects as being contributed
by cross terms in the stress-energy tensor and not others. But it's
hard to see how they could really correspond to specific particles.
Even if they could, the effects would essentially be just what you
describe; such things would tend to create gravitational fields that
circulate, rather than radiate (to put it crudely). They'd probably
create something like frame dragging effects, which are already
well-known in relativity -- but without the attractiveness.
--
Erik Max Francis && max@[EMAIL PROTECTED]
&& http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM, Y!M erikmaxfrancis
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