Rare Black Hole discovered in Cigar Galaxy

As per a recent ANI report, a team of astronomers from University of Maryland has succeeded in accurately measuring and thus confirming the existence of a black hole about 400 times the mass of our sun in Cigar Galaxy (M82). Moreover, Richard Mushotzky–a UMD astronomy professor, and Tod Strohmayer–co-author of NASA's Goddard Space Flight Center, had suspected the existance of an intermediate black hole in M82 for a decade, but at that time estimates of its mass were not definitive enough to confirm it. How has it been confirmed? In 1999, a NASA satellite telescope detected x-rays, which were dubbed M82 X-1; post that they were observed 800 times between 2004 and 2010 through NASA's RXTE (Rossi X-Ray Timing Explorer) satellite telescope.

Why is this discovery important? "Until a couple of decades ago, black holes were merely theoretical predictions. We've only recently found evidence to prove their existence and that too in very few galaxies, one being our Milky Way. This particular discovery is very interesting because while scientists believed there were supermassive black holes (millions or billion times the mass of the Sun), and very small ones (10-15 times the mass of the Sun), intermediate-sized black holes were considered non-existent. It's also exciting to know that unlike the supermassive black holes, this one is not in the centre of the galaxy," says Arvind Paranjpye, Director of Nehru Planetarium.

Did you know?

A star dies, a black hole is born

Stars die in different ways, some continue giving light till the end, some expand, oscillate and shrink, and some end their lives in a massive explosion; the last type are super-nova. Once a star expands to the extent that its mass is 10 or more times the mass of the Sun, its gravitational pull is so strong that it devours everything around it. But black holes are not a common occurance, only a small fraction of stars have this fate.

Light can't passthrough black holes If an object is thrown with such a force that it goes up at 11.2 km/sec or more, it will be able to beat the planet's gravitational pull and leave Earth. This speed is called escape velocity, Jupiter's is much higher and the Sun's is higher still. A black hole is fascinating because even light, which nothing travels faster than, cannot escape its formidable gravitational pull. It's marvellous how a star, which emits light, turns into a phenomenon, possibly the only one, that can swallow light.

Black holes can bend light

When light nears a black hole, but is still at a distance where the black hole's pull is not powerful enough to consume it, light (known to be linear) can still be bent by a black hole, which can also change its direction. According to NASA, black holes can also spur the growth of stars.

Inputs for Did you know? from Arvind Paranjpye, Director, Nehru Planetarium