Black holes are massive animals that destroy everything that dares to cross them. We don't know much about these invisible,…
Black holes are massive animals that destroy everything that dares to cross them. We don’t know much about these invisible, scary bodies, but astronomers have found a new way of studying their mysterious behavior.
By observing the x-rays blowing from a star torn by a black hole, a team of scientists could calculate how fast the black hole is spinning – clock it at nearly 50 percent speed of light. This marks the first time astronomers used X-rays, which surround the black hole every 131 seconds, to calculate their incredible speed. The research, which could help to correlate the age of a black hole with its speed, was published today in the journal Science.
The discovery dates back to November 201
4, when astronomers observed a galaxy 300 million light-years from Earth. They saw the galaxy’s central, super-massive black hole in and rip in a suitable star. Known as a tidal break, this event created a radiation of X-rays that was strong enough to be seen from the earth. Since black holes do not emit many x-rays on their own, a group of researchers decided at home on the event.
And fortunately for them, various space telescopes began to measure the black hole x-ray emission after flare was discovered. After combining their tasks, the MIT management team saw a remarkable trend. They discovered that X-ray outbreaks occurred once every 131 seconds near the black hole event horizon – the point at which it began to cool material. These periodic emissions, which lasted over 450 days, increased the black hole’s total x-ray emissions by 40 percent.
The team believes that these powerful radiation outbreaks are actually caused by two stars instead of one. The original observation in 2014 still remains: a black hole tricked into a fitting star and torn it in pieces. Some of these stearic strips, which emit massive amounts of X-rays, were sucked into the back hole. Others, however, remained in the innermost, stable circular path (ISCO) – the closest place where objects can pave a black hole without being swallowed by it.
In the dangerously close orbit, another star, who thought to be a small, dense white dwarf, lies. Scientists believe that the dwarf’s gravity pulled in the bright star remains and created an X-ray around it. These X-rays can be seen every time the star orbits the black hole, which is once every 131 seconds.
They combined the star’s orbital velocity with the black hole mass, which is believed to be one million times more massive than the sun, to find out how quickly the black hole spins. According to their calculations, the black hole rotates at almost half the speed of light.
“It’s not super fast – there are other black holes with spins that are estimated to be close to 99 percent light speed,” said Dheeraj Pasham, a postdoctoral fellow at MIT and lead author of the magazine, in a press release. “But this is the first time we can use tide breaks to limit the spins in supermassive black holes.”
These events only emit X-rays for a few hundred years, so the odds of witnessing one are incredibly rare. Nevertheless, the researchers plan to search for more flare events around both younger and older black holes. By comparing the speeds of black holes at different ages, researchers can determine whether they are faster and grow more rapidly over time. These statistics shed light on their mysterious evolution, as well as revealing how they feed on the galaxy’s stars.