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Astronomers Catch Black Hole Spitting Out Material

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Jet "bullets" emanating from the region around a black hole. Credit: NRAO, GSFC/NASA

AUSTIN, Tex.—One of the great ironies of the universe is that black holes, the ultimate vacuum cleaners, create more of a mess than they clean up. (It is a complaint that many people who finally prevailed on spouses and roommates to clean up after themselves might appreciate.) How is it that, in sucking up surrounding material, they squirt much of it right back out? A team of astronomers has now caught a black hole in the act.

The hole in question, a modest-size one located near the center of our galaxy known as H1743-322, had been known to flare up in x-rays every eight months or so, presumably as it periodically munched on a nearby star. Gregory Sivakoff of the University of Alberta and his colleagues kept watch on the black hole in mid-2009 using the Very Long Baseline Array (a worldwide array of radio telescopes) and the Rossi X-ray Timing Observatory (a satellite that NASA shut down last week after 16 years in operation). On May 28 and 30 and June 2, all seemed normal. But on June 5, the radio telescopes spotted bright knots of material flying away in opposite directions. By June 6, the knots had moved a substantial distance, implying a velocity of a quarter of the speed of light. Working backward, the team deduced the material had been shot out on June 2, 2009, at about 10:00 P.M. Universal Time, give or take half a day. The researchers announced their finding today during a meeting of the American Astronomical Society being held here.

The x-ray images, meanwhile, showed some unusual goings-on in the disk of material swirling around the black hole. On May 28 and 30, there was a spot in the disk revolving once per second. On June 2, the spot sped up threefold—and after the ejection, there was no spot at all. Sivakoff said it was a chunk of orbiting material that death-spiraled into the hole.

The researchers still need to sort out exactly how the infalling spot turned to outflying knots. One idea, Sivakoff said, is that material dragged along magnetic field lines on its way in. At some point, the field lines snapped like rubber bands; north- and south-oriented lines reconnected, unleashing energy that flung particles outward. Another idea is that the plummeting material created a shock wave that energized outgoing stuff.

Through such processes, black holes are the most powerful engines in the universe, converting gravitational energy to heat, light and kinetic energy of particles. In return for untidiness, they keep the universe a vibrant place.

George Musser About the Author: is a contributing editor at Scientific American. He focuses on space science and fundamental physics, ranging from particles to planets to parallel universes. He is the author of The Complete Idiot's Guide to String Theory. Musser has won numerous awards in his career, including the 2011 American Institute of Physics's Science Writing Award. Follow on Twitter @gmusser.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. jtdwyer 9:00 pm 01/10/2012

    Very interesting that the rotating ‘spot’ in the x-ray images disappeared after the expulsion of energy and matter from the relativistic polar jets and was not ‘frozen in time’ at the black hole’s event horizon…

    I don’t know that any material object enters the event horizon of a black hole, but I do suggest that matter can be disintegrated as it is accelerated to nearly the speed of light when approaching a black hole, very much like colliding matter in particle accelerator experiments. The nearly massless disintegrated fundamental particles may be expelled from the relativistic polar jets observed in active galaxies. At relativistic speeds even unstable particles would persist for extended durations. The mass-energy extracted from the disintegration of ingested matter may be retained and accumulated within the black hole, redirected to a dimensionless focal point of gravitationally distorted local spacteime.

    In this way the gravitational effects of enormous ingested masses can be retained within a black hole without requiring some new form of matter to fit enormous amounts of ingested matter within some dimensionless pointlike space.

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  2. 2. JamesDavis 11:13 am 01/11/2012

    Did you ever think that that black hole could just be a picky eater and it doesn’t like eating its vegetables and when mom wasn’t watching, it spat them out. Black holes must not be what we think they are. Could they be one of the first stars created and they can retain the full spectrum of light and they are actually the opposite of other stars and that mass bounced off its atmosphere because it hit a solar flair just right?

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  3. 3. daedalus2u 11:22 am 01/11/2012

    “Frozen in time” is the same as disappearing. If the frequency of photons being emitted gets infinitely red shifted, there is nothing to observe. If you red shift gammas to one cycle per century, you won’t see much at any wavelength that we can look at it with.

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  4. 4. HubertB 6:23 pm 01/15/2012

    In situations involving co-orbital asteroids, one has transferred momentum to the other. The one has increased the size of its orbit around the sun, the other has reduced the size of its orbit.
    The possibility of gravitational transferring momentum between particles or larger pieces of mass just might also apply in the vicinity of a black hole.

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