If radio waves give you radar and sound provides you sonar, what do gravitational waves give you? It seems like the setting for a comedy.
According to researchers in an article published to Physical Review Letters, the solution may be “GRADAR,” or gravitational wave “radar,” a hypothetical future device that might utilize gravitational wave reflections to map the invisible cosmos. Scientists may be able to locate dark matter or faint, exotic stars by searching for these signals and learning about the inner workings of these objects.
Gravitational waves, which were originally discovered in 2015 and are moving ripples in the very fabric of space and time, are frequently used by astronomers to see catastrophic events that are challenging to analyze with light alone, such as the merger of two black holes (SN: 2/11/2016).
However, physicists are also aware of gravitational waves’ apparently pointless ability to shift direction. According to Einstein’s theory of gravity, matter warps spacetime, and any wave travelling through these distortions will change direction. As a result, when anything releases gravitational waves, some of the signal may arrive directly at Earth while others may reach later — like an echo — after traveling along longer pathways that curve around a star or other large, heavy object.
These subsequent signals, known as “gravitational glints,” had long been assumed to be too faint to be seen by scientists. But Cleveland, Ohio-based physicists Craig Copi and Glenn Starkman made a quantum leap: Using Einstein’s theory as a foundation, they computed the strength of the signal that would result from waves scattering across the gravitational field within a star itself.
The surprising part, according to Copi, is that you appear to receive a lot greater result than you would have anticipated. We are still attempting to comprehend where that comes from and whether it is really believable since it appears too wonderful to be true.
According to the study, astronomers might be able to map the interiors of stars using gravitational glints if they can be that powerful. Even large things in space that would be difficult to find normally, such as clumps of dark matter or lone neutron stars on the far side of the observable universe, may be searched for by researchers.
Maya Fishbach, an astronomer at Northwestern University in Evanston, Illinois, who was not involved in the work, thinks it would be a “really fascinating investigation.”
But there are still reasons to exercise caution. If this phenomena holds up to more examination, according to Fishbach, scientists would first need to better understand it before they could exploit it—and that would likely be challenging.
It’s an extremely challenging calculation, adds Copi.