Preprint Open Access
Traditional Newtonian physics cannot explain many observed galactic-scale gravitational effects and phenomena. This has led to many new theories. One such theory is Dark Matter. Due to some obvious problems with the Dark Matter theory, some alternatives have been proposed. One of them is the MOND (Modified Newtonian dynamics) theory. A new field theory postulates that if gravity forces are due to an elastic field, it would also be exerted by electromagnetic waves or photons of light. The comparison in this review shows that neither Dark Matter nor MOND theories can explain all the cosmological gravitational effects observations. Attempts to combine these theories have complicated the study. However, the Gravity by electromagnetic waves theory can explain these cosmological observations.