In article ,
writes:

MOND is presented as a modification of gravity that kicks in when the
local acceleration reaches a low value.

I'm wondering whether anyone has noted the coincidence of the following
values.............(and as well, whether I've goofed in the calculations
and or the values I'm using)

According to various plots for MW stellar rotation curves, MOND kicks in
at about a radius of R =3D 1kpc =3D 3.086E19 m

In other words, the radius where the energy density of MW emissions per
second matches the energy density of the CBR happens to be at 1kpc,
where the MOND effect kicks in.

So, at least for the MW galaxy, if I've done the math right, MOND kicks
in at the same place where the energy density of light being generated
within the the interior of the MW galaxy, matches the energy density of
the CBR.

I haven't checked the numbers. As I mentioned before, Hoyle pointed out
that the stellar radiation has about the same total energy as the CMB.
Your calculation is probably a variant of this. There seems to be no
significance to this. (In that sense, it's like the fact that the
angular sizes of the Sun and Moon are the same, allowing the corona to
be seen during a solar eclipse. No-one has come up with any explanation
better than coincidence, although it is less likely than many other
coincidences in astrophysics.)

As you say, MOND "kicks in" at a given acceleration, not distance. OK,
to first order, if another galaxy is smaller (larger) then it will kick
in at a smaller (larger) radius, where the CMB flux will also be smaller
(larger). But galaxies vary in surface brightness. All else being
equal, in a low--surface-brightness galaxy, MOND will kick in at the
same distance, and the CMB flux will be the same, but the stellar flux
of course less.

There are a few coincidences related to MOND, some of which might mean
something, but this doesn't appear to be one of them.