Mond is ad hoc (underlying theory, if any, unknown) sokurious said:So maybe MOND comes into play at large distances.
everyone can have his own thumbrule for it----his own version of mond. Yes?
Smolin version MOND out of that lecture I gave the link for
says not what you say "mond comes into play at large distances"
It says mond comes into play at low accelerations
there is a lower threshhold of acceleration----whenever the centripetal acceleration falls below this threshhold then there is a geometric mean modification which brings the acceleration up a little (not up all the way to the theshhold but a little raised up towards the threshhold, from the bare Newtonian value)
this version of mond would explain the Pioneer anomaly. the vehicle was far enough from the sun that the centripetal accel. had fallen below this threshhold---and then it was larger than expected
this version of mond achieves the nice fit to the galaxy rotation curves.
when the stars are far enough from the center that their centripetal accel is down below threshhold, then their accel is larger than expected.
this threshold accel is connected to the CC.
the connection is by way of a length L = Lambda-1/2
I personally do not advocate this length L.
The big question is what is it doing in our universe----if it is related to galaxy rotation curve and to pioneer anomaly, and also to acceleration of expansion.
the length L is 9.5 billion LY. that is what, if you square it and take the reciprocal, you get the cosmological constant current estimate.