Produced by: Tarun Mishra Designed by: Manoj Kumar
In a recent study, physicists employed NASA's Chandra X-ray Observatory to unveil the rotational speed of Sagittarius A* (Sgr A*), the supermassive black hole residing at the core of our galaxy.
According to a report by Space.com, an online publication focused on space exploration, the research defined a black hole's rotation speed, denoted as "a," on a scale from 0 to 1. Sgr A*'s astonishing speed fell within the range of 0.84 to 0.96, approaching the theoretical upper limit.
Xavier Calmet, a theoretical physicist, underscored the far-reaching implications for comprehending black hole formation and associated astrophysical processes stemming from the discovery.
Black hole rotation, distinct from other celestial bodies, is governed by angular momentum, not mass distribution. The intense gravitational forces near black holes creates the ergosphere, twisting spacetime.
Black holes exhibit "frame dragging" or the "Lensing-Thirring effect," intricately twisting the fabric of space-time. Anything within the ergosphere is drawn along, a unique characteristic not shared by solid bodies like planets or stars.
The frame-dragging effect contributes to gravitational lensing, altering the trajectory of light near a rotating black hole. This results in the formation of light rings and the intriguing creation of a black hole's shadow.
The theoretical maximum speed of a black hole hinges on its matter consumption, growth, angular momentum limits, mass, and interactions with its environment, including accretion disks.
Sgr A*, with a mass akin to approximately 4.5 million suns, exhibited a rotation speed between 0.84 and 0.96. In contrast, the supermassive black hole in galaxy M87, the first ever photographed, spun at 0.89 to 0.91 despite a mass equivalent to 6.5 billion suns.
The interaction of light with a rotating black hole yields phenomena like gravitational lensing, producing captivating visual effects such as light rings and the emergence of a black hole's shadow.
These findings enrich our understanding of black hole dynamics, offering insights into their rotational behaviour and the distinct gravitational influences they exert on the space surrounding them.