New Study Suggests Gravity Exists Without Mass
What does gravity look like without mass? Newton’s groundbreaking laws universally define gravity’s effects, while Einstein’s concept of warped spacetime describes it in terms of curvature. Traditionally, scientists have associated gravity solely with matter
A recent study proposes an unconventional idea: gravity could potentially exist without mass, offering an alternative to the concept of dark matter, which remains a mysterious and hypothetical substance believed to constitute 85 percent of the Universe’s total mass.
Physicists originally conceived dark matter to explain the cohesion of rapidly rotating galaxies. Despite extensive efforts, they have not yet directly observed it, leading them to explore various unconventional theories to address gaps in current understanding
Topological Defects and Gravity Without Mass
Astrophysicist Richard Lieu from the University of Alabama in Huntsville suggests that instead of dark matter binding galaxies together, the Universe might feature thin, shell-like layers of ‘topological defects’ that generate gravitational effects without the presence of mass.
Lieu’s investigation began as an exploration for alternative solutions to Einstein’s field equations, which establish a relationship between the curvature of spacetime and the matter it contains.
Einstein’s 1915 theory of general relativity states that bundles of matter and streams of radiation shape the curvature of spacetime in the Universe. Their energy is inherently linked to mass through Einstein’s famous equation: E=mc²
Gravity and Mass-Energy Relation
Thus, an object’s mass correlates with its energy, which bends space-time—a concept Einstein described as gravity, more sophisticated than Newton’s 17th-century approximation of gravity as a force between masses. This implies that gravity is closely tied to mass.
However, Richard Lieu challenges this notion. In his research, Lieu tackled a simplified version of the Einstein field equations to explore the possibility of a finite gravitational force in the absence of detectable mass.
He explains, “My work was driven by frustration with the current consensus, particularly the persistence of dark matter’s existence despite a century of lacking direct evidence.”
Shell-Shaped Topological Defects in Dense Space Regions
In fact, Lieu’s hypothesis involves shell-shaped topological defects that could exist in extremely dense regions of space. These shells consist of a thin layer of positive mass surrounded by an outer layer of negative mass, effectively canceling each other out to yield a total mass of zero.
Despite this, stars located near these shells would experience a significant gravitational pull towards the center.
“My argument in the paper is that these shells are potentially massless,” Lieu asserts. If his controversial proposals hold weight, he suggests, “there would be no need to continue the seemingly endless search for dark matter.”
However, the next challenge is to determine how to validate or disprove the shells proposed by Lieu through observations.
“The growing number of observations showing galaxies with ring and shell-like formations in the Universe provides support for the type of source proposed here,” Lieu notes in his paper. However, he acknowledges that his proposed solution is “highly suggestive” and alone cannot disprove the dark matter hypothesis.
“At best, it could be an intriguing mathematical exercise,” Lieu concludes. “Yet, it represents the first mathematical proof that gravity can exist independently of mass.”
Read the original article on: Science ALert
