2blackholes

1. a black hole is a place in space where the gravitonal pull is so strong that not even light can get out.
2. a black hole has an invisible inside. you would be able to see it by the matter around it. media type="youtube" key="EOi0xA9GvX8" height="344" width="425" 3. the idea of gravity being strong enough to prevent light from escaping was proposed by john michell 4. black holes are formed when the remenant of dead stars collapse on themselves 5. the effects of quantum mechanics indicates that black holes slowly leak energy called hawking radiation, and eventually die 6. The no hair theorem states that in a steady state, a black hole has only three independent physical properties which are mass, charge and angular momentum. 7. the main feature of a black hole is the event horizon. 8. once something crosses the event horizon, it can not escape from the black hole. 9. black holes are not all black because the emmit small amounts of radiation 10. falling in a black hole would deform atoms and even composite nucleons in a proccess called spaghettification. 11. once a black hole has formed it will keep growing by absorbing matter. it will absorb interstellar dust but not enough that it would make a difference in the black holes total mass.

Black holes are the evolutionary endpoints of stars at least 10 to 15 times as massive as the Sun. If a star that massive or larger undergoes a supernova explosion, it may leave behind a fairly massive burned out stellar remnant. With no outward forces to oppose gravitational forces, the remnant will collapse in on itself. The star eventually collapses to the point of zero volume and infinite density, creating what is known as a " singularity ". As the density increases, the path of light rays emitted from the star are bent and eventually wrapped irrevocably around the star. Any emitted photons are trapped into an orbit by the intense gravitational field; they will never leave it. Because no light escapes after the star reaches this infinite density, it is called a black hole.

Gravitational collapse occurs when an object's internal pressure is insufficient to resist the object's own gravity. For stars this usually occurs either because a star has too little "fuel" left to maintain its temperature, or because a star which would have been stable receives a lot of extra matter in a way which does not raise its core temperature. In either case the star's temperature is no longer high enough to prevent it from collapsing under its own weight (the ideal gas law explains the connection between pressure, temperature, and volume). The collapse may be stopped by the degeneracy pressure of the star's constituents, condensing the matter in an exotic denser state. The result is one of the various types of compact star. Which type of compact star is formed depends on the mass of the remnant - the matter left over after changes triggered by the collapse (such as supernova or pulsations leading to a planetary nebula) have blown away the outer layers. Note that this can be substantially less than the original star - remnants exceeding 5 solar masses are produced by stars which were over 20 solar masses before the collapse. If the mass of the remnant exceeds ~3-4 solar masses either because the original star was very heavy or because the remnant collected additional mass through accretion of matter)—even the degeneracy pressure of neutrons is insufficient to stop the collapse. After this no known mechanism (except maybe the quark degeneracy pressure, see quark star) is powerful enough to stop the collapse and the object will inevitably collapse to a black hole.   This gravitational collapse of heavy stars is assumed to be responsible for the formation of most (if not all) stellar mass black holes  http://imagine.gsfc.nasa.gov/docs/science/know_l2/black_holes.html http://images.google.com/imgres? imgurl=http://universe.nasa.gov/press/images/blackhole/bhole2bulge_chart.jpg&imgrefurl=http://universe.nasa.gov/press/2003.html&usg=__7zoHl5SL07ustd3HLBxmt2Dq0Iw=&h=198&w=300&sz=8&hl=en&start=15&sig2=etWZETUu0bQYSVjEle6QOQ&tbnid=Tqg78UuyTJpzcM:&tbnh=77&tbnw=116&prev=/images%3Fq%3Dblack%2Bhole%2Bchart%26gbv%3D2%26hl%3Den%26safe%3Doff&ei=6OXCSZryHpjcmQfc3cnqCw

http://en.wikipedia.org/wiki/Black_holes http://cosmology.berkeley.edu/Education/BHfaq.html media type="google" key="3869172164167982669&hl=en&fs=true" width="400" height="326"