Wherever you go in the Universe, gravity exists. It is inextricably woven into its structure, forming stars and planets, and choreographing the dance of galaxies. It is what keeps our world together and us in it; However, even after more than a century of studying gravity through Einstein’s theory of general relativity, scientists are still discovering surprising new ways it can behave. But a new discovery by physicists Luca Comisso of Columbia University and Felipe A. Asenjo of Adolfo Ibáñez University in Chile may take the relativity cookie. Their new calculations suggest that gravitational fields can break down and reconnect in new configurations, just as magnetic fields do on the Sun. “We are not modifying general relativity or introducing new physics beyond it. Rather, we are identifying physical principles that have remained unknown for more than a century,” Comisso told ScienceAlert. frameborder=”0″ enable=”accelerometer; autoplay; writing on clipboard; encrypted media; gyroscope; picture in picture; web-share” referrerpolicy=”strict-origin-when-cross-origin” enablefullscreen> Our everyday experience of gravity is that of a force that keeps us more or less on the ground. But there is more than just attraction. According to relativity, gravity is described by a field: the curvature of space-time caused by mass and energy, which influences how matter and light move through the Universe. The equations that describe this curvature are a masterpiece of physics, allowing Physicists predict everything from the The bending of starlight in the face of gravitational waves produced by colliding black holes, and they have survived test after test in the classical Universe But the Universe also has other types of fields to find a few: vast magnetic fields that pass through charged solar plasma, whose tangled strands can break and reconnect in a process called magnetic reconnection, releasing the energy that fuels solar flares. Asenjo have shown mathematically, gravity can have a similar trick in their repertoire. “We had suspected that gravity might share some properties with magnetic fields, since it has long been known that Einstein’s equations can be rewritten in ways that resemble the equations of electromagnetism,” Comisso explained. “However, we did not know how far this analogy would extend. It was only after working through analytical calculations, step by step on the blackboard, that we realized how closely gravitational fields could follow the same principles that govern magnetic fields in plasmas.” The revelation began with an earlier paper the pair published along with a third co-author, physicist Maricarmen A. Winkler of Adolfo Ibáñez University. Their calculations showed that, under certain conditions, gravitational fields can behave as if their connections were frozen in place. Instead, preserving the links between different regions even as space-time evolves. They realized that this behavior has a surprising analogue in the magnetic fields of electrically charged plasma, where the field lines can remain connected even when the plasma flows and changes shape. But, as we have already established, magnetic fields do not always behave this way. When the conditions that keep their field lines connected are broken, those connections can be reorganized through magnetic reconnection, changing which regions are linked by the field. So, it seemed natural to ask whether the same could also be true for gravity. To find out, Comisso and Asenjo went back to Einstein’s equations, using a mathematical formulation that reveals similarities between gravity and electromagnetism. They investigated what happens when the conditions that preserve the connections of gravitational fields are broken and discovered that, under certain circumstances, the fields can reconnect in new configurations, a process they call gravitational reconnection. The gravitational field forms sheets that extend across four-dimensional space-time (three dimensions of space and one of time),” Comisso explained. Field lines, these sheets are not physical objects, but rather mathematical structures that help us visualize the gravitational field. As space-time evolves, these sheets can stretch, bend and, under certain conditions, break and reconnect in a new arrangement.” “This does not mean that spacetime itself is torn apart, but rather that the gravitational field changes the way different regions of spacetime are connected.” Even gravitational waves from colliding black holes (arguably the strongest events the Universe can trigger) change the length of LIGO’s 4-kilometer arms by less than the width of a proton. But now we’re talking about the physical implications. “What I find particularly notable is that these principles give us a new way of understanding the complex dynamics of space-time in relatively simple physical terms,” Comisso said. As magnetic reconnection has transformed our understanding of how magnetic energy is released in plasmas, gravitational reconnection could provide an equally powerful framework for understanding how gravitational fields evolve and exchange energy and momentum with matter. occur (LIGO/T. Pyle) Researchers believe gravitational reconnection could occur in a variety of astrophysical environments, such as black hole mergers or star collapses. Numerical simulations, Comisso said, could help identify the conditions under which it occurs and characterize how the process unfolds. One particularly tantalizing possibility is that gravitational reconnection could leave a distinctive signature in the gravitational waves emitted by colliding black holes. “Our work provides the theoretical basis for gravitational reconnection, but we still need to determine the precise conditions under which it occurs in nature and understand its role in astrophysical phenomena,” Comisso said. “For us, this is one of the most interesting questions our research has opened up, and we are eager to investigate further.” McDonald. While we take pride in our process, we are human. If you spot an error, please let us know.
