FREE ESSAY ON BLACK HOLE

BLACK HOLE

If theories of their existence are true, black holes are the most powerful force in the
known physical universe. Many people are familiar with the term black hole, but few
people actually know anything 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 to collapse under it's own intense, inward
gravity (Chaisson, 193). It is like slowly letting the air out of a balloon. Once the
star is compacted to a certain size, while it's mass, or weight, remains the same, its
gravity becomes so powerful that nothing can escape it (Hawking, 87). This critical size
to weight ratio is known as the Schwarzchild Radius (Hawking, 87). Once a black hole is
created in this way, an invisible area, or line around it exists. If any object crosses
this line, it can no longer escape the gravitational 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 very common anomaly in this universe. In 1915, Albert Einstein put forth the first
real proposition of such an 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 holes mathematically. Since then, black holes have become
a very important and integral part of science and the over all understanding of the
universe. It has been proven, mathematically, that black holes have infinite, gravity
based, escape velocities and an immense effect on light, time and even the very fabric of
space. 
All bodies in space have gravity. According to Einstein's "Theory of Relativity", this is
because bodies with a large mass, or weight, actually warp space (Chaisson, 77). For
example, if a two dimensional sheet of cloth, stretched and suspended at four corners,
represents space, and a bowling ball is placed in the center, the sheet will warp
downward. If a golf ball is then set at the edge of the sheet and allowed to move freely
it will be attracted toward the bowling ball, unless the golf ball is traveling at a
speed great enough to not be effected by the curve. This critical speed is known as an
escape 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's radius
(Chaisson, 77). For example, if a body's mass is two-hundred, and it's size is twelve and
one half, the escape velocity would be four. If the size of the same body is reduced to
two, while it's mass 
remained at two-hundred, the escape velocity increases to ten. Since a black hole's size
is always decreasing and it's weight is always the same, the escape velocity is infinite
(Chaisson, 195). This means 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 of light govern that it must be subject to forces of
nature, such as gravity. Light travels at such a high speed that it is not observably
effected by gravity, unless that gravity is very strong. A black hole's gravity is
powerful enough to trap light because it's 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 (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 time moves slower at higher speeds (Hawking, 86). An experiment was
conducted in which two synchronized atomic clocks were used. One was placed in a jet and
flown around the Earth at three times the speed of sound, while the other was left
stationary, on the ground (Hawking, 22). When the jet landed and the clocks were
compared, the one in the jet displayed an earlier time. This leads to the reasoning that
time is just as volatile as light or dirt. In cosmology, a singularity is 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, it has no
future (Hawking, 88). Absolutely nothing in the known universe can survive in or escape
from a black hole, so it can be said logically 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. If
the mathematics that describe a black hole are reversed, the outcome is an object called
a 
white hole (Bunn, 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 (Bunn, Black
Holes FAQ). At this point, white holes are strictly theory. Their existence is highly
improbable. 
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
(Bunn, Black Holes FAQ). This leads to an even more improbable occurrence called a
wormhole (Bunn, Black Holes FAQ). In theory, a wormhole would truly be a tear in the
fabric of space. Since time essentially has no effect on a black or white hole, if an
object 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 a wormhole, it could probably avoid hitting the
singularity (Bunn, Black Holes FAQ). Therefore it would not be turned into spaghetti and
compacted to the size of a base particle. Instead, it would follow the closest thing to a
straight line that it could find, which would be to slip completely through the wormhole
(Bunn, Black Holes FAQ). It sounds impossible, but it looks good on paper. If wormholes
could exist, according to calculations, they would be highly unstable (Bunn, Black Holes
FAQ). If anything were to disturb it, like an object passing through it, it would likely
collapse (Bunn, Black Holes FAQ). Though the equations are valid, wormholes most
assuredly do not exist. If they did it would probably send shivers up the science fiction
community's spine. 
In the book, Relatively Speaking, the Author, Eric Chaisson says, "The world of science
is littered with mathematically elegant theories that apparently have no basis in
reality" (182). Although 
black holes have not been conclusively proven to exist, there is strong evidence, in the
observable universe, that they do. Black holes are very important to the world of
cosmology. They allow for the study of common particles under very uncommon environmental
variables. scientists have vastly increased their knowledge of the universe and the
properties of matter through the study of a black holes effects on light, time and the
fabric of the space. 
Works Cited
Bunn, Ted "Black Holes FAQ." NSF Science and Technology Center (September 1995): Online.

Internet. http://physics7.berkeley.edu/Bhfaq.HTML 
Chaisson, 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:
Bantam 
Books, 1988.