A recent study that presents new challenges to the existence of dark matter suggests gravity may be able to exist even in the absence of mass. Although all life on Earth experiences its effects daily, gravity remains one of the great mysteries of modern physics. Now, a new study published by Dr. Richard Lieu with The University of Alabama in Huntsville (UAH) proposes that the gravitational effects observed in galaxies and clusters may be the result of what he likens to topological defects in the universe, a theory that does not require the inclusion of dark matter to explain phenomena...