Black Holes: Infinity and Beyond
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 itís 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 itís mass, or weight, remains the same, itís
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 ďTheory of RelativityĒ (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 Einsteinís ďTheory of RelativityĒ, 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 bodyís gravitational force
(Chaisson, 77). If a body is compacted, such that itís weight stays the same but itís radius, or size,
becomes smaller, itís escape velocity increases in parallel (Chaisson, 196). The simple formula for this,
in physics, states that a bodyís escape velocity is equal to the square root of itís mass, divided by itís
radius (Chaisson, 77). For example, if a bodyís mass is two-hundred, and itís size is twelve and one
half, the escape velocity would be four. If the size of the same body is reduced to two, while itís mass
remained at two-hundred, the escape velocity increases to ten. Since a black holeís size is always
decreasing and itís 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 holeís
gravity is powerful enough to trap light because itís 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, therefor the black hole appears as a void in