A paper based upon solar system dynamics largely rules out the remaining parameter space for primordial black holes. The abstract states:
N.B.: A solar mass is about 2*10^33 grams. So, this is equivalent to a range of 10^-15 to 10^-11 solar masses.
A paper based upon solar system dynamics largely rules out the remaining parameter space for primordial black holes. The abstract states:
MOND equivalence of f (R) gravity theory in
ReplyDeletesolar system and cosmological scalarons
Debojit Paul1∗ and Sanjeev Kalita,1†
1Department of Physics, Gauhati University, Guwahati-781014, Assam, India
Abstract
Since last two decades f (R) gravity theory has been extensively used as a serious
alternative of general relativity to mimic the effects of dark energy. The theory presents
a Yukawa correction to Newtonian gravitational potential, acting as a fifth force of
Nature. Generally speaking, this new force is mediated by a scalar field known as
scalaron. It affects orbital dynamics of test bodies around a central mass. When
the scalaron becomes extremely massive f (R) gravity reduces to Newtonian theory in
the weak field limit. In this paper we test f (R) gravity theory in the solar system
by constraining scalaron mass through existing measurements of perihelion shift of
planets, Cassini’s measurement of the Parameterised Post Newtonian parameter and
measurement of the Brans-Dicke coupling constant. We calculate acceleration due
to gravity in the theory for planets, Trans Neptunian Objects (TNOs), Centaurs,
Scattered Disk Objects (SDOs) and Oort cloud objects and compare it with the values
predicted by Newtonian and Modified Newtonian Dynamics (MOND). It is found that
the theory reproduces to MOND like acceleration in the outer solar system (rp ∼ 2000
au - 36000 au) for available interpolating functions of the MOND paradigm. From
its MOND equivalence we constrain the parameters of the theory. Our results are
consistent with existing constraints on the theory arising from the environment of the
Galactic Centre black hole. Scalarons realized in the solar system are reproduced in
the radiation era of the universe with a time varying mass
The f(R) paper doesn't add up. There shouldn't be any MOND effects anywhere near the outer solar system.
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