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What would happen if we go too close to a black hole RRS feed

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  • It is impossible for a human to travel very near a high gravity star which has a mass like that of the Sun. If, somehow, a person could survive the extremely harmful radiation that would be emitted on or near these objects, the high gravity itself would likely pose insurmountable problems. The person could not stand casually on the surface of such a star because the high surface gravity would tend to flatten them. (Lying down wouldn't help.) Were a person to orbit the star in a spaceship, however, the immense gravitational field would be overcome by a large outward centrifugal acceleration.[1] The problem in this case, however, is the extreme change in gravity between the head and toe of the person, the extreme tidal pull, would surely prove much more than annoying for any human[2].

    Nevertheless it is informative and interesting to wonder what it would look like to visit such a high gravity environment. Significant speculations on this include popular science fiction stories such as those by Forward [3] and Niven [4]. A discussion (with cartoon drawings) of a trip to a black hole appears in Kaufmann's book ``The Cosmic Frontiers of General Relativity" [2]. A description of what hot spots on a high gravity neutron star would look like to an observer far away is given by Ftaclas, Kearney, and Pechenick, [5]. Other descriptions include what a typical neutron star would look like to a distant observer including a computer drawn wire mesh diagram Devil, a description of the sky as seen from the vicinity of a black hole [7-9], a description of the image of a thin accretion disk around a black hole [10], a description of how the observer would see self-images near a black hole [11], and a short computer animated movie simulating a trip around a black hole while facing the constellation Orion by Palmer and Unruh [12]. In general, however, the professional science literature has focused mainly on mathematical detail rather than observable image distortions.

    In this paper the visual aspects of a journey to several different types of high gravity stars will be discussed in some detail, along with computer generated illustrations highlighting the perceived visual distortions. The three types of stars that will be discussed are a) a "normal" neutron star having relatively weak surface gravity, b) a black hole, and c) an "ultracompact" neutron star [13] having relatively strong surface gravity. Here the speed of the traveler will always be considered small when compared to the local speed of light, so special relativistic effects will be ignored.

    Monday, October 8, 2007 10:50 AM

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  • It is impossible for a human to travel very near a high gravity star which has a mass like that of the Sun. If, somehow, a person could survive the extremely harmful radiation that would be emitted on or near these objects, the high gravity itself would likely pose insurmountable problems. The person could not stand casually on the surface of such a star because the high surface gravity would tend to flatten them. (Lying down wouldn't help.) Were a person to orbit the star in a spaceship, however, the immense gravitational field would be overcome by a large outward centrifugal acceleration.[1] The problem in this case, however, is the extreme change in gravity between the head and toe of the person, the extreme tidal pull, would surely prove much more than annoying for any human[2].

    Nevertheless it is informative and interesting to wonder what it would look like to visit such a high gravity environment. Significant speculations on this include popular science fiction stories such as those by Forward [3] and Niven [4]. A discussion (with cartoon drawings) of a trip to a black hole appears in Kaufmann's book ``The Cosmic Frontiers of General Relativity" [2]. A description of what hot spots on a high gravity neutron star would look like to an observer far away is given by Ftaclas, Kearney, and Pechenick, [5]. Other descriptions include what a typical neutron star would look like to a distant observer including a computer drawn wire mesh diagram Devil, a description of the sky as seen from the vicinity of a black hole [7-9], a description of the image of a thin accretion disk around a black hole [10], a description of how the observer would see self-images near a black hole [11], and a short computer animated movie simulating a trip around a black hole while facing the constellation Orion by Palmer and Unruh [12]. In general, however, the professional science literature has focused mainly on mathematical detail rather than observable image distortions.

    In this paper the visual aspects of a journey to several different types of high gravity stars will be discussed in some detail, along with computer generated illustrations highlighting the perceived visual distortions. The three types of stars that will be discussed are a) a "normal" neutron star having relatively weak surface gravity, b) a black hole, and c) an "ultracompact" neutron star [13] having relatively strong surface gravity. Here the speed of the traveler will always be considered small when compared to the local speed of light, so special relativistic effects will be ignored.

    Monday, October 8, 2007 10:50 AM
  • Many people think that nothing can escape the intense gravity of black holes. If that were true, the whole Universe would get sucked up. Only when something (including light) gets within a certain distance from the black hole, will it not be able to escape.
    Imagine an object with such an enormous concentration of mass in such a small radius that its escape velocity was greater than the velocity of light. Then, since nothing can go faster than light, nothing can escape the object's gravitational field, that is, only if that thing is in the event horizon. Even a beam of light would be pulled back by gravity and would be unable to escape.

    Event horizon is the place where the escape velocity equals the velocity of light. Outside of the horizon, the escape velocity is less than the speed of light, so if you fire your rockets hard enough, you can give yourself enough energy to get away. But if you find yourself inside the horizon, then no matter how powerful your rockets are, you can't escape.

    But farther away, things do not get sucked in. Stars and planets at a safe distance will circle around the black hole, much like the motion of the planets around the Sun. The gravitational force on stars and planets orbiting a black hole is the same as when the black hole was a star because gravity depends on how much mass there is, the black hole has the same mass as the star, it's just compressed.

    Monday, October 8, 2007 5:42 PM