Recent discoveries offer some tantalizing evidence that black holes have a dramatic influence on the neighborhoods around them - emitting powerful gamma ray bursts, devouring nearby stars, and spurring the growth of new stars in some areas while stalling it in others. Most black holes form from the remnants of a large star that dies in a supernova explosion.
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Smaller stars become dense neutron stars, which are not massive enough to trap light. If the total mass of the star is large enough about three times the mass of the Sun , it can be proven theoretically that no force can keep the star from collapsing under the influence of gravity.
However, as the star collapses, a strange thing occurs. As the surface of the star nears an imaginary surface called the "event horizon," time on the star slows relative to the time kept by observers far away.
Shedding light on black holes
When the surface reaches the event horizon, time stands still, and the star can collapse no more - it is a frozen collapsing object. Even bigger black holes can result from stellar collisions. Soon after its launch in December , NASA's Swift telescope observed the powerful, fleeting flashes of light known as gamma ray bursts. Chandra and NASA's Hubble Space Telescope later collected data from the event's "afterglow," and together the observations led astronomers to conclude that the powerful explosions can result when a black hole and a neutron star collide, producing another black hole.
Although the basic formation process is understood, one perennial mystery in the science of black holes is that they appear to exist on two radically different size scales. On the one end, there are the countless black holes that are the remnants of massive stars.
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Peppered throughout the Universe, these "stellar mass" black holes are generally 10 to 24 times as massive as the Sun. Astronomers spot them when another star draws near enough for some of the matter surrounding it to be snared by the black hole's gravity, churning out x-rays in the process. Most stellar black holes, however, lead isolated lives and are impossible to detect. Judging from the number of stars large enough to produce such black holes, however, scientists estimate that there are as many as ten million to a billion such black holes in the Milky Way alone.
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On the other end of the size spectrum are the giants known as "supermassive" black holes, which are millions, if not billions, of times as massive as the Sun. Astronomers believe that supermassive black holes lie at the center of virtually all large galaxies, even our own Milky Way.
Astronomers can detect them by watching for their effects on nearby stars and gas. Historically, astronomers have long believed that no mid-sized black holes exist. One possible mechanism for the formation of supermassive black holes involves a chain reaction of collisions of stars in compact star clusters that results in the buildup of extremely massive stars, which then collapse to form intermediate-mass black holes.
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The star clusters then sink to the center of the galaxy, where the intermediate-mass black holes merge to form a supermassive black hole. Black Holes Don't let the name fool you: a black hole is anything but empty space. Intense X-ray flares thought to be caused by a black hole devouring a star. Watch the Video. Watch the video. Astronomers have identified a candidate for the smallest-known black hole. This chart shows the relative masses of super-dense cosmic objects. Read the full article.
More information: Erik Curiel.
taylor.evolt.org/qylac-dating-gay.php The many definitions of a black hole, Nature Astronomy DOI: Provided by Ludwig Maximilian University of Munich. Citation : What exactly is a black hole?
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What is a black hole?
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Won't it take forever for you to fall in? Won't it take forever for the black hole to even form?