What Is The Black Hole Essay Research — страница 2

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telescopes, or other instruments, we interpret the speed and movement and see what they ve bounced off. It was discovered, in 1676, by Danish astronomer, Ole Christenson, that light travels at a very high, but finite speed (Hawking 18). These properties of light govern that it must be subject to forces of nature, such as gravity, and a black hole has more than enough gravity to spare. Light travels at such a high speed that it is not affected by gravity, unless that gravity is very strong. A black hole s gravity is powerful enough to trap light because its escape velocity, being infinite, exceeds the speed of light (Hawking 82). This is why a black hole is black. Once light crosses the event horizon, it is drawn into the hole in space. Although the light is still hitting objects,

it is not able to bounce off to indicate their existence to an observer, therefore the black hole appears as a void in space. Closing in on the edge of the event horizon, light travels back to an observer at a slower and slower rate, until it finally becomes invisible. This is due to heavy gravity and the effect that a black hole has on time (Black Holes FAQ). However, with a creative observation used in physics, it is possible to indirectly observe a black hole. Scientists routinely measure an object s gravitational pull by its affect on the objects around it. Picture this: You must find a black cat in a coal mine. You can neither see the black cat nor the coal. However, there is a spool of glow-in-the-dark yarn in the mine. You see a string of the yarn twisting around and know

that the cat is playing with it, even though you cannot see the cat. Imagine the coal mine is space, the cat is a black hole, the ball of yarn is a star, and the string attached to the ball is matter being expelled by the star, known as the star s accertion disc (Black Holes FAQ). In rare instances scientists will find a star near a black hole, a binary star system where one of the stars has imploded into a black hole. Physicists can observe matter being expelled from the star and being pulled toward another object before the matter vanishes, or passes the event horizon (Hetche). According to Einstein s General Theory of Relativity , time is not a constant (Hawking 87). Time is relative to an observer and his or her environment (Hawking 87). It has been proven that time moves

slower at higher speeds (Hawking 87). In other words, time can be just as volatile as light or dirt. An example of this aspect of time is a singularity; an event or point that has a future or a past, but not both (Hawking 49). In human life, death would be considered a singularity. A black hole is also considered a singularity. If an object crosses the event horizon of a black hole, it relatively ceases to exist, because it has no future, since it can never escape. There is the chance that time slows or stops the closer you get to the center of the black hole (Hawking 88); since absolutely nothing in the known universe can survive in or escape from a black hole. It can be said that time is stopped within the event horizon. The only way for an object to escape this fate would be

for a strange anomaly to occur in the fabric of space, caused by a theoretically different type of black hole than is generally excepted. If the mathematics that describe this black hole are reversed, the outcome is an object called a white hole (Black Holes FAQ). As the complete opposite of a black hole, a white hole is an object into which nothing can fall and objects are only spit out (Black Holes FAQ). At this point, white holes are strictly theory. Their existence is highly unlikely. If certain properties, such as motion or a positive or negative charge are applied to a black hole, then the possibility of a white hole forming within the event horizon arises (Black Holes FAQ). This leads to an even more improbable occurrence called a wormhole (Black Holes FAQ). In theory, a

wormhole would be a tear in the fabric of space. Since time essentially has no effect on a black or white hole, due to the event horizon, if an object were to fall into a wormhole, it could be spit out anywhere in time or space (Black Holes FAQ). How is it possible to test this theory if no signals can escape the black hole? Simple, enter the black hole yourself. Suppose one were the captain of a starship, three or four hundred years in the future, and one approached a black hole. What would one see? Nothing, no thing, which is what will tell you that the black hole is there. Due to the hole s light absorbing properties, you wouldn t be able to detect any of the stars behind it. Because no signals emanate from the black hole, you wouldn t be able to tell anything more about it