Einstein’s Theory of Gravity and the Problem of Missing Mass
Pedro G. Ferreira1,* and
Glenn D. Starkman2,*
The observed matter in the universe accounts for just 5% of
the observed gravity. A possible explanation is that Newton’s
and Einstein’s theories of gravity fail where gravity
is either weak or enhanced. The modified theory of Newtonian
dynamics (MOND) reproduces, without dark matter, spiral-galaxy
orbital motions and the relation between luminosity and rotation
in galaxies, although not in clusters. Recent extensions of
Einstein’s theory are theoretically more complete. They
inevitably include dark fields that seed structure growth, and
they may explain recent weak lensing data. However, the presence
of dark fields reduces calculability and comes at the expense
of the original MOND premise, that the matter we see is the
sole source of gravity. Observational tests of the relic radiation,
weak lensing, and the growth of structure may distinguish modified
gravity from dark matter.
2 Center for Education and Research in Cosmology and Astrophysics, Institute for the Science of Origins, Department of Physics, Case Western Reserve University, Cleveland, OH 44106 USA.
* To whom correspondence should be addressed. E-mail: p.ferreira1{at}physics.ox.ac.uk (P.G.F.); glenn.starkman{at}case.edu (G.D.S.)
