If theories of their existence are true, black holes are the most powerful force in the knownphysical universe. Many people are familiar with the term black hole, but few people actually knowanything about them. A black hole forms as a result of a massive star running out of fuel to burn(Chaisson, 193). Once the star is no longer exerting outward force by burning off gases, it begins tocollapse under it’s own intense, inward gravity (Chaisson, 193). It is like slowly letting the air out of aballoon. Once the star is compacted to a certain size, while it’s mass, or weight, remains the same, it’sgravity becomes so powerful that nothing can escape it (Hawking, 87).
This critical size to weight ratiois known as the Schwarzchild Radius (Hawking, 87). Once a black hole is created in this way, aninvisible area, or line around it exists. If any object crosses this line, it can no longer escape thegravitational force of the black hole (Hawking, 87). This line is called the event horizon (Hawking, 87). If black holes are proven to exist, beyond theoretical physics, then they would probably be a verycommon anomaly in this universe. In 1915, Albert Einstein put forth the first real proposition of suchan anomaly in his ?Theory of Relativity? (Bunn, Black Holes FAQ).
In the 1930s, three physicists,doctors Volkoff, Snyder and Oppenheimer, were able to prove the validity of black holesmathematically. Since then, black holes have become a very important and integral part of science andthe over all understanding of the universe. It has been proven, mathematically, that black holes haveinfinite, gravity based, escape velocities and an immense effect on light, time and even the very fabricof space. All bodies in space have gravity. According to Einstein’s ?Theory of Relativity?, this is becausebodies with a large mass, or weight, actually warp space (Chaisson, 77). For example, if a twodimensional sheet of cloth, stretched and suspended at four corners, represents space, and a bowlingball is placed in the center, the sheet will warp downward.
If a golf ball is then set at the edge of thesheet and allowed to move freely it will be attracted toward the bowling ball, unless the golf ball istraveling at a speed great enough to not be effected by the curve. This critical speed is known as anescape velocity. This is the speed at which an object must travel to escape a body’s gravitational force(Chaisson, 77). If a body is compacted, such that it’s weight stays the same but it’s radius, or size,becomes smaller, it’s escape velocity increases in parallel (Chaisson, 196).
The simple formula for this,in physics, states that a body’s escape velocity is equal to the square root of it’s mass, divided by it’sradius (Chaisson, 77). For example, if a body’s mass is two-hundred, and it’s size is twelve and onehalf, the escape velocity would be four. If the size of the same body is reduced to two, while it’s massremained at two-hundred, the escape velocity increases to ten. Since a black hole’s size is alwaysdecreasing and it’s weight is always the same, the escape velocity is infinite (Chaisson, 195).
Thismeans that nothing can escape a black hole past the event horizon, not even light. Light is made up of waves and particles. It was discovered, in 1676, by Danish astronomer,Ole Christenson, that light travels at a very high, but finite speed (Hawking, 18). These properties oflight govern that it must be subject to forces of nature, such as gravity. Light travels at such a highspeed that it is not observably effected by gravity, unless that gravity is very strong.
A black hole’sgravity is powerful enough to trap light because it’s escape velocity, being infinite, exceeds the speedof light (Hawking, 82). This is why a black hole is black. Once light crosses the event horizon it isdrawn into the hole in space. Although the light is still hitting objects, it is not able to bounce off toindicate their existence to an observer, therefor the black hole appears as a void in space. Closing in onthe edge of the event horizon, light travels back to an observer at a slower and slower rate, until itfinally becomes invisible. This is due to heavy gravity and the effect that a black hole has on time(Bunn, Black Holes FAQ).
According to Einstein’s ?General Theory of Relativity?, time is not a constant (Hawking, 86). Time is relative to an observer and his or her environment (Hawking, 86). It has been proven that timemoves slower at higher speeds (Hawking, 86). An experiment was conducted in which twosynchronized atomic clocks were used.
One was placed in a jet and flown around the Earth at threetimes the speed of sound, while the other was left stationary, on the ground (Hawking, 22). When thejet landed and the clocks were compared, the one in the jet displayed an earlier time. This leads to thereasoning that time is just as volatile as light or dirt. In cosmology, a singularity is an event or point thathas a future or a past, but not both (Hawking, 49).
In human life, death would be considered asingularity. A black hole is also considered a singularity. If an object crosses the event horizon of ablack hole, it relatively ceases to exist, it has no future (Hawking, 88). Absolutely nothing in the knownuniverse can survive in or escape from a black hole, so it can be said logically that time is stoppedwithin the event horizon. The only way for an object to escape this fate would be for a strange anomalyto occur in the fabric of space, caused by a theoretically different type of black hole.
If the mathematics that describe a black hole are reversed, the outcome is an object called awhite hole (Bunn, Black Holes FAQ). As the complete opposite of a black hole, a white hole is anobject into which nothing can fall and objects are only spit out (Bunn, Black Holes FAQ). At this point,white holes are strictly theory. Their existence is highly improbable. If certain properties, such asmotion or a positive or negative charge are applied to a black hole, then the possibility of a white holeforming within the event horizon arises (Bunn, Black Holes FAQ). This leads to an even moreimprobable occurrence called a wormhole (Bunn, Black Holes FAQ).
In theory, a wormhole wouldtruly be a tear in the fabric of space. Since time essentially has no effect on a black or white hole, if anobject were to fall into a worm hole, it could conceivably be spit out anywhere in time or space (Bunn,Black Holes FAQ). If an object falls into a black hole, which has undergone the transformation into awormhole, it could probably avoid hitting the singularity (Bunn, Black Holes FAQ). Therefor it wouldnot be turned into spaghetti and compacted to the size of a base particle. Instead, it would follow theclosest thing to a straight line that it could find, which would be to slip completely through thewormhole (Bunn, Black Holes FAQ). It sounds impossible, but it looks good on paper.
If wormholescould exist, according to calculations, they would be highly unstable (Bunn, Black Holes FAQ). Ifanything were to disturb it, like an object passing through it, it would likely collapse (Bunn, BlackHoles FAQ). Though the equations are valid, wormholes most assuredly do not exist. If they did itwould probably send shivers up the science fiction community’s spine. In the book, Relatively Speaking, the Author, Eric Chaisson says, ?The world of science islittered with mathematically elegant theories that apparently have no basis in reality? (182). Althoughblack holes have not been conclusively proven to exist, there is strong evidence, in the observableuniverse, that they do.
Black holes are very important to the world of cosmology. They allow for thestudy of common particles under very uncommon environmental variables. Scientists have vastlyincreased their knowledge of the universe and the properties of matter through the study of a blackholes effects on light, time and the fabric of the space. Works CitedBunn, Ted ?Black Holes FAQ. ? NSF Science and Technology Center (September 1995): Online.
Internet. http://physics7. berkeley. edu/Bhfaq. HTMLChaisson, Eric.
Relatively Speaking: Relativity, Black Holes, and the Fate of the Universe. New York:W. W. Norton & Company, 1988. Hawking, Stephen.
A Brief History of Time: From the Big Bang to Black Holes. New York: BantamBooks, 1988.