Re: Gravitomagnetic monopole?

On Mar 3, 6:43 pm, Tim Little <t...@[EMAIL PROTECTED]
> wrote:
> On 2008-03-03, Erik Max Francis <m...@[EMAIL PROTECTED]
> wrote:
>
> > Magnetic charge is called poles, but they always show up in equal
> > and opposite pairs, hence "dipoles."  A hypothetical isolated
> > magnetic charge, or pole, is a monopole -- and "monopole" only makes
> > sense if you're talking about some kind of field charge that only
> > comes in equal and opposite pairs.
>
> In weak-field GR I seem to recall that a system can have a monopole
> moment, and quadrupole moment, but no dipole moment.  I may be wrong
> on this.

You can always get a dipole moment by choosing an origin away from the
center of mass of a monopole.  On the other hand, dipole radiation is
forbidden by conservation of momentum.  Maybe that's what you were
thinking of?

Luke