The Search For Black Holes: Both As A Concept And An Understanding Essay, Research Paper
The Search for Black Holes: Both As A Concept And An Understanding
For ages people have been determined to explicate on everything. Our
search for explanation rests only when there is a lack of questions. Our skies
hold infinite quandaries, so the quest for answers will, as a result, also be
infinite. Since its inception, Astronomy as a science speculated heavily upon
discovery, and only came to concrete conclusions later with closer inspection.
Aspects of the skies which at one time seemed like reasonable explanations are
now laughed at as egotistical ventures. Time has shown that as better
instrumentation was developed, more accurate understanding was attained. Now it
seems, as we advance on scientific frontiers, the new quest of the heavens is to
find and explain the phenomenom known as a black hole.
The goal of this paper is to explain how the concept of a black hole
came about, and give some insight on how black holes are formed and might be
tracked down in our more technologically advanced future. Gaining an
understanding of a black hole allows for a greater understanding of the concept
of spacetime and maybe give us a grasp of both science fiction and science fact.
Hopefully, all the clarification will come by the close of this essay.
A black hole is probably one of the most misunderstood ideas among
people outside of the astronomical and physical communities. Before an
understanding of how it is formed can take place, a bit of an introduction to
stars is necessary. This will shed light (no pun intended) on the black hole
philosophy.
A star is an enormous fire ball, fueled by a nuclear reaction at its
core which produces massive amounts of heat and pressure. It is formed when two
or more enormous gaseous clouds come together which forms the core, and as an
aftereffect the conversion, due to that impact, of huge amounts of energy from
the two clouds. The clouds come together with a great enough force, that a
nuclear reaction ensues. This type of energy is created by fusion wherein the
atoms are forced together to form a new one. In turn, heat in excess of
millions of degrees farenheit are produced.
This activity goes on for eons until the point at which the nuclear fuel
is exhausted. Here is where things get interesting. For the entire life of the
star, the nuclear reaction at its core produced an enormous outward force.
Interestingly enough, an exactly equal force, namely gravity, was pushing inward
toward the center. The equilibrium of the two forces allowed the star to
maintain its shape and not break away nor collapse.
Eventually, the fuel for the star runs out, and it this point, the
outward force is overpowered by the gravitational force, and the object caves in
on itself. This is a gigantic implosion. Depending on the original and final
mass of the star, several things might occur. A usual result of such an
implosion is a star known as a white dwarf. This star has been pressed together
to form a much more massive object. It is said that a teaspoon of matter off a
white dwarf would weigh 2-4 tons. Upon the first discovery of a white dwarf, a
debate arose as to how far a star can collapse. And in the 1920?s two leading
astrophysicists, Subrahmanyan Chandrasekgar and Sir Arthur Eddington came up
with different conclusions. Chandrasekhar looked at the relations of mass to
radius of the star, and concluded an upper limit beyond which collapse would
result in something called a neutron star. This limit of 1.4 solar masses was
an accurate measurement and in 1983, the Nobel committee recognized his work and
awarded him their prize in Physics. The white dwarf is massive, but not as
massive as the next order of imploded star known as a neutron star. Often as
the nuclear fuel is burned out, the star will begin to shed its matter in an
explosion called a supernovae. When this occurs the star loses an enormous
amount of mass, but that which is left behind, if greater than 1.4 solar masses,
is a densely packed ball of neutrons. This star is so much more massive that a
teaspoon of it?s matter would weigh somewhere in the area of 5 million tons in
earth?s gravity. The magnitude of such a dense body is unimaginable. But even
a neutron star isn?t the extreme when it comes to a star?s collapse. That
brings us to the focus of this paper. It is felt, that when a star is massive
enough, any where in the area of or larger than 3-3.5 solar masses, the collapse
would cause something of a much greater mass. In fact, the mass of this new
object is speculated to be infinite. Such an entity is what we call a black
hole. After a black hole is created, the gravitational force continues to pull
in space debris and all other types of matter in. This continuous addition
makes the hole stronger and more powerful and obviously more massive. The
simplest three dimensional geometry for a black hole is a sphere. This type of
black hole is called a Schwarzschild black hole. Kurt Schwarzschild was a
German astrophysicist who figured out the critical radius for a given mass which
would become a black hole. This calculation showed that at a specific point
matter would collapse to an infinitely dense state. This is known as
singularity. Here too, the pull of gravity is infinitely strong, and space and
time can no longer be thought of in conventional ways. At singularity, the laws
defined by Newton and Einstein no longer hold true, and a “myterious” world of
quantum gravity exists. In the Schwarzschild black hole, the event horizon, or
skin of the black hole, is the boundary beyond which nothing could escape the
gravitational pull.
Most black holes would tend to be in a consistent spinning motion, because of
the original spin of the star. This motion absorbs various matter and spins it
within the ring that is formed around the black hole. This ring is the
singularity. The matter keeps within the Event Horizon until it has spun into
the center where it is concentrated within the core adding to the mass. Such
spinning black holes are known as Kerr Black Holes. Roy P. Kerr, an Australian
mathematician happened upon the solution to the Einstein equations for black
holes with angular momentums. This black hole is very similar to the previous
one. There are, however, some differ
existing ones. The singularity in the this hole is more time-like, while the
other is more space-like. With this subtle difference, objects would be able to
enter the black whole from regions away from the equator of the event horizon
and not be destroyed.
The reason it is called a black hole is because any light inside of the
singularity would be pulled back by the infinite gravity so that none of it
could escape. As a result anything passing beyond the event horizon would
dissappear from sight forever, thus making the black hole impossible for humans
to see without using technologicalyl advanced instruments for measuring such
things like radiation. The second part of the name referring to the “hole” is
due to the fact that the actual hole, is where everything is absorbed and where
the center core presides. This core is the main part of the black hole where
the mass is concentrated and appears purely black on all readings even through
the use of radiation detection devices.
The first scientists to really take an in depth look at black holes and
the collapsing of stars, were a professor, Robert Oppenheimer and his student
Hartland Snyder, in the early nineteen hundreds. They concluded on the basis of
Einstein’s theory of relativity that if the speed of light was the utmost speed
over any massive object, then nothing could escape a black hole once in it’s
clutches. It should be noted, all of this information is speculation. In theory,
and on Super computers, these things do exist, but as scientists must admit,
they?ve never found one. So the question arises, how can we see black holes?
Well, there are several approaches to this question. Obviously, as realized
from a previous paragraph, by seeing, it isn?t necessarily meant to be a visual
representation. So we?re left with two approaches. The first deals with X-ray
detection. In this precision measuring system, scientists would look for areas
that would create enormous shifts in energy levels. Such shifts would result
from gases that are sucked into the black hole. The enormous jolt in
gravitation would heat the gases by millions of degrees. Such a rise could be
evidence of a black hole. The other means of detection lies in another theory
altogether. The concept of gravitational waves could point to black holes, and
researchers are developing ways to read them. Gravitational Waves are predicted
by Einstein?s General Theory of Relativity. They are perturbations in the
curvature of spacetime. Sir Arthur Eddington was a strong supporter of Einstein,
but was skeptical of gravity waves and is reported to have said, “Graviatational
waves propagate at the speed of thought.” But what they are is important to a
theory. Gravitational waves are enormous ripples eminating from the core of the
black hole and other large masses and are said to travel at the speed of light,
but not through spacetime, but rather as the backbone of spacetime itself.
These ripples pass straight through matter, and their strength weakens as it
gets farther from the source. The ripples would be similar to a stone dropped
in water, with larger ones toward the center and fainter ones along the outer
circumference. The only problem is that these ripples are so minute that
detecting them would require instrumentation way beyond our present capabilities.
Because they?re unaffected by matter, they carry a pure signal, not like X-rays
which are diffused and distorted. In simulations the black hole creates a
unique frequency known as it natural mode of vibrations. This fingerprint will
undoubtedly point to a black hole, if it?s ever seen.
Just recently a major discovery was found with the help of The Hubble Space
Telescope. This telescope has just recently found what many astronomers believe
to be a black hole, after being focused on a star orbiting an empty space.
Several picture were sent back to Earth from the telescope showing many computer
enhanced pictures of various radiation fluctuations and other diverse types of
readings that could be read from the area in which the black hole is suspected
to be in.
Because a black hole floats wherever the star collapsed, the truth is, it can
vastly effect the surrounding area, which might have other stars in it. It
could also absorb a star and wipe it out of existance. When a black hole
absorbs a star, the star is first pulled into the Ergosphere, this is the area
between the event horizon and singularity, which sweeps all the matter into the
event horizon, named for it’s flat horizontal appearance and critical properties
where all transitions take place. The black hole doesn?t just pull the star in
like a vaccuum, rather it creates what is known as an accretion disk which is a
vortex like phenomenom where the star?s material appears to go down the drain of
the black hole. When the star is passed on into the event horizon the light
that the star ordinarily gives off builds inside the ergosphere of the black
hole but doesn?t escape. At this exact point in time, high amounts of radiation
are given off, and with the proper equipment, this radiation can be detected and
seen as an image of emptiness or as preferred, a black hole. Through this
technique astronomers now believe that they have found a black hole known as
Cygnus X1. This supposed black hole has a huge star orbiting around it,
therefore we assume there must be a black hole that it is in orbit with.
Science Fiction has used the black hole to come up with several movies and
fantastical events related to the massive beast. Tales of time travel and of
parallel universes lie beyond the hole. Passing the event horizon could send
you on that fantastical trip. Some think there would be enough gravitational
force to possible warp you to an end of the universe or possibly to a completely
different one. The theories about what could lie beyond a black hole are
endless. The real quest is to first find one. So the question remains, do they
exist?
Black holes exist, unfortunately for the scientific community, their life is
restricted to formulas and super computers. But, and there is a but, the
scientific community is relentless in their quest to build a better means of
tracking. Already the advances of hyper-sensitive equipment is showing some
good signs, and the accuracy will only get better.