Re: Is the Sun mostly dark matter ?

Bob Remeaux wrote:
I'm not able to give the exact figures, but the principle is like this.

A spiral galaxy has a dense 'roughly spherical' core and an outer disc. The mass within a radius r goes as r^3 for the core and r^2 for the disc (since the disc exists in 2 dimensions only).

If we look at the velocity curve for stars within galaxies, the central region corresponds to Newtonian theory; but across the disc the curve indicates that the mass distribution is not proportional to r^2, but is nearer to r^3.

This suggests that in addition to the visible matter there is some unseen matter that follows a more spherical distribution than is seen visibly.

Or that suggests that gravity works differently at low accelerations, as per Modified Newtonian Dynamics.

Yousuf Khan
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