Sabine Hossenfelder is offering a new version
of modified Newtonian dynamics, or MOND, which she calls Covariant Emergent
Gravity, or CEG. She explains it at her blog Backreaction here and in an arXiv paper here. She shows that CEG fits the data on the radial acceleration of
stars in galaxies much better than particle dark matter. There’s no doubt that
she’s right. The problem is that there’s ample evidence for the existence of
dark matter, and no known reason why the acceleration of gravity should
suddenly change at some distance from a center of mass.
The solution is that the particle model for
dark matter is wrong; dark matter is not a particle. As I’ve explained here
and here,
at the end of inflation spacetime is left in a state of coherent oscillations,
which decay into standard model particles. It’s usually assumed that all of
this oscillatory energy decayed immediately after the inflationary period, but
this is incorrect; only about 16% of it decayed. The rest is still there in
space. It’s energy, so it gravitates, or in the language of General Relativity,
it curves spacetime, which means, of
course, that it modifies gravity. Other researchers have published the ideas
that 1) dark matter is a remnant
of inflation, and 2) spacetime
curvature without matter would act just like dark matter. The reason that
nobody has realized that this is the answer they’re looking for is that they
don’t know what spacetime is. That,
of course is the main subject of this blog.
Now look what we have. MOND and CEG are just
forms of spacetime curvature without matter. Dark matter is spacetime curvature
without matter. See the connection? Modified gravity versus dark matter is a moot
question because modified gravity is
dark matter, just not particle dark matter.
