Dr. Richard Lieu from The University of Alabama in Huntsville (UAH) has published a study that challenges the existence of dark matter. The study suggests that gravity may exist even without mass.
Dark matter is a hypothetical nonluminous material believed to make up a large portion of the universe’s mass. It was first proposed in 1932 by Dutch astronomer Jan Oort to explain certain gravitational effects that could not be accounted for by Einstein’s theory of general relativity. Despite extensive searches, evidence for dark matter has not been confirmed.
Lieu’s study takes a different approach that could change our understanding of the universe’s mass and gravitational forces. He explains that his inspiration came from searching for another solution to the gravitational field equations of general relativity, specifically the Poisson equation applicable to galaxies and clusters. Lieu claims his interpretation “gives a finite gravitational force in the absence of any detectable mass.” His theory involves concentric structures formed by shell-like topological defects, likely originating in an early cosmological phase transition.
Gravity through massless topological effects
This phase transition would generate gravitational effects without mass. Topological defects are compact regions of space with a very high density of matter, usually in the form of cosmic strings or spherical shells,” Lieu explains.
These shells could consist of an inner layer of positive mass and an exterior layer of negative mass, creating a net zero mass structure. Despite having no mass, objects near these shells would still experience significant gravitational forces. According to Einstein’s theories, gravity warps space-time, causing interactions between objects regardless of their mass.
Lieu suggests that deflection of light and stellar orbit velocities in galaxies might be better explained by these hypothetical massless shells rather than dark matter. Although Lieu does not currently provide a method for forming these massless shells, he believes his theory could lead to new discoveries that might resolve longstanding questions or even confirm the existence of dark matter. The availability of a second solution, even if highly suggestive, is not sufficient to discredit the dark matter hypothesis,” Lieu notes.
However, if further research supports his theory, it could signify a major advancement in our understanding of the universe and one of its most enduring mysteries. Lieu’s study, “The binding of cosmological structures by massless topological defects,” appeared in the Monthly Notices of the Royal Astronomical Society.
