Weird Light Yields Clues About Mysterious Black Hole Dance  

Weird Light Yields Clues About Mysterious Black Hole Dance  

Long ago and far away, a duo of dancing supermassive black holes appear to be spiraling in towards one another, eventually doomed to collide in a stupendous, almost unimaginable, cosmic smash-up. Dancing in the dark, the strange pair will merge a mere million years from now, liberating energy equivalent to 100 million supernova blasts, in which massive stars perish. The dark-hearts of most, if not all, large galaxies in the Universe–including our own Milky Way–contain supermassive black holes with masses equivalent to millions, or even billions, of Suns,   Black Studies   and these objects of incredible darkness and their host galaxies appear to evolve together, or “co-evolve”. Theory predicts that as galaxies collide and eventually merge, growing more and more massive as a result, so too do their hearts of darkness. In the January 7, 2015 issue of the journal Nature, a team of astronomers report on a weird repeating light signal from a distant quasar that they say is most likely the result of a duo of dancing supermassive black holes in the last act of a merger–something that is predicted from theory but which has never been seen before! A quasar is an extremely brilliant, luminous object that out-dazzles all of the stars in its host galaxy combined, and is visible from across the entire Universe!

Black holes by themselves are impossible to observe, cloaked as they are in impenetrable darkness. However, their gravity can hoist in ambient gas to create a whirling, swirling band of material that is termed an accretion disk. The jitter-bugging particles of the disk are accelerated to enormous speeds and liberate stupendous quantities of energy in the form of heat and powerful X-rays and gamma rays. When this strange process occurs in the case of a supermassive black hole, the result is a quasar.

Quasars are valuable probes of the evolution of galaxies and their central black holes,” noted Dr. George Djorgovski in a January 7, 2015 California Institute of Technology (Caltech) Press Release. Dr. Djorgovski is a professor of astronomy and director of the Center for Data-Driven Discovery at Caltech, which is in Pasadena, California.

The discovery of this dancing duo of supermassive black holes could help shed new light on a long-standing mystery in astrophysics termed the final parsec problem. The final parsec problem refers to the failure of theoretical models to predict what the end stages of a black hole merger look like or even how long this incredible process might take.

“The end stages of the merger of these supermassive black hole systems are very poorly understood. The discovery of a system that seems to be at this late stage of its evolution means we now have an observational handle on what is going on,” explained the study’s lead author, Dr. Matthew Graham, in the January 7, 2015 Caltech Press Release. Dr. Graham is a senior computational scientist at Caltech.

Dancing In The Dark

Supermassive black holes lurking in the secretive, hidden hearts of galaxies, grow by devouring their surroundings, feasting hungrily on gas and the stuff of doomed stars with unimaginable greed. They are also very sloppy, and attempt to swallow more than they actually can, violently hurling some of the tattered remains of their terrible feast into the surrounding space.

Black holes are anything but empty space–despite their name. Actually, they represent a great quantity of matter packed into a very small space–and they come in at least two sizes, supermassive and stellar mass. There may also be intermediate mass black holes that are much heavier than those of “only” stellar mass, but considerably lighter than their supermassive kin.

Black holes of stellar mass form when a very heavy star collapses in the fiery tantrum of a supernova explosion that blasts the dying, massive star into oblivion–thus heralding the end of its beautiful, active life as a main-sequence (hydrogen-burning) star. After a black hole has emerged from the stellar mess, it can go on to gain more and more weight by devouring whatever it can snare with its gravitational claws that snatch. Many astronomers think that by eating doomed stars, blobs of gas, and by merging with others of its own strange kind, supermassive beasts form from the smaller variety.

Astronomers have known for years that it is probable every large galaxy in the Universe harbors a hungry, greedy, supermassive beast in its mysterious heart. There the strange object resides, secreted in its host galaxy’s core, waiting for its lunch to tumble down into its ravenous maw.

Clouds of gas and doomed stars swirl around in the violent maelstrom surrounding supermassive black holes, thus forming the immense, brilliant accretion disk. This ill-starred material grows ever hotter and hotter, and emits a tremendous amount of radiation, especially as it approaches the dreadful point of no return called the event horizon, which is the innermost region of the accretion disk.

 

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