Physics is shit

So you have this gravity law. But does particle attract itself?

I.e. does it work like (mapcar (lambda (X) (gravity X Xs)) Xs) or X should be excluded from Xs, before gravity applies?

>>1
There are no particles, only fields and perturbations in them.

Consider this: how do you know that the sun has mass and what it is?

You can choose some sphere containing the sun, measure the strength of its gravity field in enough points on the sphere, and get the total flux of the field through its surface.

Note that you should not add up magnitudes, but projections of the field on the normal, in case your sphere is off-center. Also note that you can similarly calculate the rotation of the field (called curl or rotor): http://en.wikipedia.org/wiki/Curl_(mathematics), and these two properties on the sphere completely define the the field everywhere else.

Then you posit that the space is 3-dimensional, and the flux and curl conservation rules (for spheres or other shapes that do not enclose any field sources, the flux and curl over the surface sum to zero), and you immediately get the field equations which describe the inverse square rule (square because the area of a 3d sphere is proportional to the square of its radius), but point-wise.

So then you say that these rules that describe the evolution of a field point-wise are the real shit, while the idea that the sun "attracts" stuff is an interpretation, so when this interpretation breaks as you ask "does the sun attract itself", that's OK, you just consult the real thing and it's all fine there.

It's a damn shame that http://en.wikipedia.org/wiki/Black_hole_electron doesn't work.