Re: Is the Sun mostly dark matter ?

Yousuf Khan wrote:
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

What critical tests can be made to distinguish between MOND and standard Gravity + dark matter?
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