September 18, 2016

Galaxy Torn Apart By Rival Black Holes


Every kid knows that stars twinkle. Now scientists who have ­discovered an entire galaxy flickering say they could be witnessing the muzzle flashes of two supermassive black holes at war. 
An Australian-led study has found that the galaxy Markarian 1018, which astronomers were forced to reclassify when it suddenly brightened in the 1980s, has darkened again. While space ­gazers have detected other galaxies changing intensity, few have done so twice or so ­dramatically.

The team says the huge black hole at the centre of the galaxy, more than a million times as massive as our sun, could be ­running out of stars and gas to feed on. But University of Sydney PhD student Rebecca McElroy, who discovered the latest change, said the data suggested something else was afoot. One possib­ility is another black hole has crashed the feast, disrupting the fuel supply and throwing the entire galaxy into cosmic mayhem.

Astronomers believe that within the last billion years — which is recent, in astronomical terms — Mrk 1018 merged with a neighbouring galaxy.

“When galaxies get close to one another they begin to orbit together and eventually coal­esce,” Ms McElroy said. “Most galaxies have supermassive black holes, and if you throw two galaxies at each other there are going to be two black holes that will eventually sink to the centre.”

By John Ross
With many thanks to The Australian