The supermassive black hole at the heart of our galaxy isn’t just spinning — it’s doing so at almost maximum speed, dragging anything near it along for the ride.
Physicists calculated the rotational speed of the Milky Way’s supermassive black hole, called Sagittarius A* (Sgr A*), by using NASA’s Chandra X-ray Observatory to view the X-rays and radio waves emanating from outflows of material.
The spin speed of a black hole is defined as “a” and given a value from 0 to 1, with 1 being the maximum rotational speed to a particular black hole, which is a significant fraction of the speed of light. Ruth A. Daly, a physicist at Penn State, and colleagues found that the rotational speed of Sgr A* is between 0.84 and 0.96 — close to the top limit defined by a black hole’s width. The team described Sgr A*’s blistering speed in a study published Oct. 21 in the journal Monthly Notices of the Royal Astronomical Society.
“Discovering that Sgr A* is rotating at its maximum speed has far-reaching implications for our understanding of black hole formation and the astrophysical processes associated with these fascinating cosmic objects,” Xavier Calmet, a theoretical physicist at the University of Sussex who was not involved in the research, told Live Science in an email. [Continue reading…]