At 02:52 pm 22/02/2006 -0500, you wrote: > > >It would be simpler (but declared laughable ) to explain it by saying the >_inertia_ of a body is a function of _where_ it is. > >Thus the stars on the outer edges of the galaxy do not fly off because of >more than expected gravity, but because of less than expected inertia. > >In other words Newton was right about gravity, but wrong about inertia. > >Harry
Some years ago I wrote a little computer program which assumed that the stars were spiralling in towards the galactic centre in accordance with a inverse distance law. By adding a bit of randomness to the star positions I got a very plausible picture of a spiral galaxy. Try it for yourselves. Basically the exercise was based on seeing the inverse square law of gravity as the difference between two inverse linear laws, with the incoming gravitation pressure pushing stars together being slightly greater than the outgoing radiation pressure pushing stars apart. A bit like solar radiation, eh! 8-) On the galactic scale this gravitational radiation is polarised and we have 1/r incoming along the galactic plane and 1/(r + delta) outgoing perpendicular to the galactic plane. Cheers, Frank Grimer
