Researcher suggests gravity can exist without mass, mitigating the need for hypothetical dark matter

Dark matter is a hypothetical form of matter implied by gravitational effects that cannot be explained by general relativity unless there is more matter in the universe than we can see. It remains almost as mysterious as it was nearly a century ago when it was first proposed by Dutch astronomer Jan Oort in 1932 to explain the so-called “missing mass” needed to clump things like galaxies together.

Now Dr. Richard Lieu of the University of Alabama in Huntsville (UAH) published an article in the Monthly notices of the Royal Astronomical Society that shows for the first time how gravity can exist without mass, providing an alternative theory that could potentially mitigate the need for dark matter.

“My own inspiration came from my search for another solution to the gravitational field equations of general relativity – the simplified version of which, applicable to the conditions of galaxies and clusters of galaxies, is known as the Poisson equation – which gives a finite force of gravity in the absence of any observable mass,” said Lieu, a distinguished professor of physics and astronomy at UAH, part of the University of Alabama System.

“This initiative, in turn, is driven by my frustration with the status quo, namely the idea of ​​the existence of dark matter, despite the absence of any direct evidence for an entire century.”

The researcher claims that the ‘excess’ gravity needed to bind a galaxy or cluster together could instead be due to concentric sets of shell-like topological defects in structures commonly found in the cosmos and most likely during The early universe was created when a phase transition occurred. . A cosmological phase transition is a physical process in which the overall state of matter in the entire universe changes together.

“It is currently unclear what precise form of phase transition in the universe could lead to these types of topological defects,” says Lieu.

“Topological effects are very compact regions of space with a very high matter density, usually in the form of linear structures known as cosmic strings, although 2D structures such as spherical shells are also possible.

‘The shells in my article consist of a thin inner layer of positive mass and a thin outer layer of negative mass; the total mass of both layers – the only thing you can measure in terms of mass – is exactly zero, but as a star, if it is on this scale, it experiences a strong gravitational pull that pulls it towards the center of the scale.”

Because gravity essentially involves the warping of space-time itself, it allows all objects to interact with each other, whether they have mass or not. For example, massless photons have been confirmed to experience gravitational effects from astronomical objects.

“The gravitational bending of light by a series of concentric single shells forming a galaxy or cluster is caused by a ray of light being bent slightly inward – that is, towards the center of the large-scale structure, or the series of shells – as it passes through one grenade,” Lieu notes.

‘The overall effect of the passage through many shells is a finite and measurable total deflection that mimics the presence of a large amount of dark matter in much the same way as the speed of the orbits of stars.

‘Both the deflection of light and the orbital speeds of stars are the only way one can measure the strength of the gravitational field in a large-scale structure, be it a galaxy or a cluster of galaxies. The thesis of my article is that at the very least the shells it posits are massless. There is then no need to continue this seemingly endless search for dark matter.”

Questions for future research will likely focus on how a galaxy or cluster is formed by the alignment of these shells, as well as how the evolution of the structures occurs.

“This paper does not attempt to address the problem of structure formation. A controversial point is whether the garnets were initially planes or even straight strings, but angular momentum excites them. There is also the question of how the proposed garnets can be confirmed or refuted by dedicated observations. Of course, the availability of a second solution, even if highly suggestive, is not in itself sufficient to discredit the dark matter hypothesis, it could be an interesting mathematical exercise at best,” Lieu concludes .

“But it is the first evidence that gravity can exist without mass.”