Everyday we look out upon the night sky, wondering and dreaming of what lies beyond our planet. The universe that we live in is so diverse and unique, and it interests us to learn about all the variance that lies beyond our grasp. Within this marvel of wonders our universe holds mysteries that are very difficult to understand because of the complications that arise when trying to examine and explore the principles of space. Within our galaxy alone, there are millions upon millions of stars. Humans have known the existence of stars since they have had eyes. Although interpretations may have differed on what they were, they were always thought of as white glowing specks in the sky, but the mystery does not lie within what we can see, but what we cannot see. The object, which we cannot see is called black hole. Imagine if you will, an object resting in the vast emptiness of space, totally undetectable except for its gravitational pull. Imagine an object so massive, and so densely packed, that not even light can escape its immense gravity. Now imagine flying toward one of these objects and circling around it at some distance; its strong gravitational field bends light from the stars behind it. Now imagine approaching and orbiting the photosphere. Think of falling deeper and deeper towards the black hole, as tidal forces stretch your body into spaghetti. Imagine spiraling inward toward a singularity in space-time, an infinitely dense geometric point where all the laws of physics, in fact the very fabric of space and time, break down and cease to exist. These are strange and fascinating objects, but as of yet, they are still considered theoretical. This essay will hopefully give you the knowledge and understanding of the how the concept of a black hole came about, structure of it, and two different kind to black holes. It gives some insight on how black holes are formed and how it functions. It will also give some idea how we can see black holes, and also talks about some theories of black hole. This paper also explain how the calculation of black hole mass is done, it also talks what kind the effects it has on the universe, and how it might be tracked down in our more technologically advanced future.
The name "black hole" was named such, because of the fact that light could not escape from the gravitational pull from the core, and that makes the black hole impossible for humans to see without using technological advancements for measuring such things like radiation. The second part of the word was named "hole" 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. A black hole is a region of space so tightly packed with matter that nothing, not even light can escape. Hidden at its center is a tear in the fabric of space-time. Stephen Hawking showed in the mid-seventies that black holes aren't actually black.1 They glow in the dark. They emit radiation via microscopic processes that occur just outside the horizon. This means black holes ultimately evaporate. In reality, though, a solar mass black hole will take many times the lifetime of the Universe to evaporate. In some sense, a black hole marks a boundary to space-time: a horizon beyond which no one can see without traveling through it. This radius of no return is called the event horizon of the black hole. All the bumps and wriggles of the matter from which they were formed are smoothed out as the matter contracts, so that the final shape of the horizon is always perfectly smooth and round. Once a giant star dies and a black hole has formed, all its mass is squeezed into a single point.2 At this point, both space and time stop. It's very hard for us to imagine a place where mass has no volume and time does not pass, but that's what it is like at the center of a black hole. The point at the center of a black hole is called a singularity. Within a certain distance of the singularity, the gravitational pull is so strong that nothing--not even light--cans escape.3 That distance is called the event horizon. The event horizon is not a physical boundary but the point-of-no-return for anything that crosses it. When people talk about the size of a black hole, they are referring to the size of the event horizon. The more mass the singularity has, the larger he event horizon. The structure of a black hole is something like this: 4
A black hole is an extremely dense outer space body that has been theorized to exist in the universe. The gravitational field of a black hole is so strong that, if the body is large enough, nothing, including electromagnetic radiation, can escape from its area. The body is surrounded by a spherical boundary, called a horizon, through which light can enter but to escape; it therefore appears totally black. The idea of a mass concentration so dense that even light would be trapped goes all the way back to Laplace in the 18th century. Almost immediately after Einstein developed general relativity, Karl Schwarzschild discovered a mathematical solution to the equations of the theory that described such an object. 5 The radius of the horizon of an Schwarzschild black hole depends only on the mass of the body, being 2.95 km (1.83 mi) times the mass of the body in solar units (the mass of the body divided by the mass of the sun). 6 If a body is electrically charged or rotating, Schwarzschild’s results are modified. According to general relativity, gravitation severely modifies space and time near a black hole. As the horizon is approached from outside, time slows down relative to that of distant observers, stopping completely on the horizon. Once a body has contracted within its Schwarzschild radius (radius of the horizon), it would theoretically collapse to a dimensionless object of infinite density.
There are two kinds of black holes. Static is an Schwarzschild black hole, and a charged, which is a Reissner-Nordstrom black hole. 7 However, in this paper I will talk about only one type of black hole. Why is it called the Static black hole? It is called that name because it does not have charge and it is not rotating. This is your standard, idealistic, simple black hole. It is also called an Schwarzschild black hole. The interesting places for this one are the photon sphere, the event horizon, and the singularity. What happens to you near the black hole, all depends on your distance in Schwarzschild radii. Let us say that you're flying towards a static black hole in a brand new, spaceship. You're approaching the black hole slowly, since only a fool would charge full-speed into one. The black hole itself is very plain and quite difficult to see. It's the space around it that is interesting. When you a black hole, you will see multiple images of many of the stars. That galaxy that you know is behind the black hole appears as a ring around the black hole, commonly called an Einstein ring. Why you see the galaxy at all, when the black hole is between you and it, and why it appears as a ring is from the bending of light due to the strong force of gravity of the black hole. Say you have an iron marble and a bar magnet. If you roll the ball near enough the magnet, it veers towards the magnet. The marble ends up tracing a slightly bent path versus the straight path it would have traced had it not encountered the magnet. Now replace the magnet with the black hole, and the marble with a light ray, and you've got it. The light from the 'hidden' galaxy peeks around the black hole and looks like a ring. The singularity of a charged black hole is the same as that of a static black hole with the exception that it is possible for the singularity to exist without any protective horizons. Truly, there is one other important difference: you can avoid the singularity of a charged back hole, whereas you must eventually encounter that static black hole. Encountering a singularity is not something you want to do, I can assume. In a static black hole, once inside the event horizon, that's it end of your life. However, should you survive the trip between the outer event horizon and the inner one of a charged black hole, you could in theory turn around and leave the black hole back and return to your own universe, or you could go into another universe.
Gaining an understanding of a black hole allows for a greater understanding of the concept of space-time and maybe gives 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 on the black hole philosophy. A star is an enormous fireball, fueled by a nuclear reaction at its core, which produces massive amounts of heat and pressure. 8 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 where the atoms are forced together to form a new one. In turn, heat in excess of millions of degrees Fahrenheit is 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. 9 Eventually, the fuel for the star runs out, and it this point, the gravitational force overpowers the outward 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. 10 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. 11 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 warded him their prize in Physics. The white dwarf is massive, but not as massive as he next order of imploded star known as a neutron star. Often as the nuclear fuel is burned out, the star will begin toshed its matter in an explosion called a supernova. 12 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. 13 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. 14 The simplest three-dimensional geometry for a black hole is a sphere. This type of black hole is called an 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. 15 A specific point matter would collapse to infinitely dense states, and they are 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 "mysterious" 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. 16 This motion absorbs various matters 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 he 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.17 This black hole is very similar to the previous one. There are, however, some differences, which make it more viable for real, existing ones. The singularity in the 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 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. 18 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. We will first deals with X-ray detection. In this precision measuring system, scientists would look for areas that would create enormous shifts in energy levels. 19 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. Einstein’s General Theory of Relativity predicts Gravitational Waves. 20 They are perturbations in the curvature of space-time. Sir Arthur Eddington was a strong supporter of Einstein, but was skeptical of gravity waves and is reported to have said, "Gravitational waves propagate at the speed of thought. 21 But what they are is important to a theory. Gravitational waves are enormous ripples emanating from the core of the black hole and other large masses and are said to travel at the speed of light, but not through space-time, but rather as the backbone of space-time 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. 22 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. 23 Because a black hole floats wherever the star collapsed, the truth is, it can vastly affect the surrounding area, which might have other stars in it. It could also absorb a star and wipe it out of existence. 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 vacuum, rather it creates what is known as an accretion disk which is a vortex like phenomenon 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 X1.24 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 warps 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. 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 the scientific community is relentless in their quest to build a better means of tracking. Already the advances of hypersensitive equipment are showing some good signs, and the accuracy will only get better. 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. 25 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. 26 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. 27 The simple formula for this, in physics, states that a body’s scape velocity is equal to the square root of its mass, divided by its radius. 28 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. 29 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. 30 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 affected 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. 31 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. 32 According to Einstein’s “General Theory of Relativity”, time is not a constant. 33 Time is relative to an observer and his or her environment. 34 It has been proven that time move slower at higher speeds an experiment was conducted in which two synchronized atomic clocks were used. 35 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. 36 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. 37 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. 38 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 describes a black hole is reversed, the outcome is an object called a white hole. 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 39. 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. 40 This leads to an even more improbable occurrence called a wormhole. 41 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 wormhole, it could conceivably be spit out anywhere in time or space. 42 If an object falls into a black hole, which has undergone the transformation into a wormhole, it could probably avoid hitting the singularity. 43 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. 44 It sounds impossible, but it looks good on paper. If wormholes could exist, according to calculations, they would be highly unstable. 45 If anything were to disturb it, like an object passing through it, it would likely collapse. 46 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. 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 black holes effects on light, time and the fabric of the space.
A black hole is suggested to be the end product of a large star that is collapsing into it, due to the fact that gravitational acceleration is calculated by the formula. A=Gmb/ r^6. 47 Where mb is the mass of the black hole, as the radius, r, of the star decreases, the gravitational field on its surface increases. 48 This causes a chain reaction in which a greater force is put on the star to collapse, thus decrease in size even further, and the gravity of its surface increases. It is suggested that a star would have to have a mass equivalent to three times that of our Sun to become a black hole. If though a star with an equivalent mass to the Earth were to collapse into a black hole, the space that all if the matter would take up would have a radius of less than 9mm. It is easy to see that the density of this would be huge-thus demonstrating why it would have such notable effects. The gravitational field created would have important effects to its surrounding environment, producing signs for astronomers to observe when looking for a black hole.
Einstein’s theory of general relativity suggests that close to the star itself, strong distortions occur in the structure of space. He found that the acceleration was equal when caused by changing motion, compared to when changed by gravitational fields. 49 From this, we deduce that at the point of a gravitational field, space is actually curved such that moving particles follow the same path as they would if they were being accelerated. This has applications toward photons of light as well as any other particle. 50 The effects of this gravitational field produce an enhancement of the curvature of space, in terms of a photon of light projected from the surface of the star that is not directly along the path of the normal. It becomes deflected, causing an increased angle compared to the angle that it was projected at. Similarly, light that grazes the surface of a strong gravitational sphere is deflected in the same way. The stronger the gravitational field is, the greater angle of deflection and the greater the velocity of the wave that has to be projected to escape the field. As the density increases, the field’s pull is so great that the photon of the light is directed horizontally at the field and deflected into the orbit of the star. The star’s light may be projected from the surface of the star to escape its gravitational field. When the projection’s angle is equal to that of the normal, the light is projected away at any other angle than that of the normal. 51 The stronger the gravitational field, the greater the deflection, and the smaller the angle becomes that the light is allowed to project away from the surface without being pulled into orbit. Thus as the star becomes more dense, its gravitational field’s strength increased, until eventually the angle at which light is allowed to project away from the star is zero degrees. As light has the greatest velocity of anything known, and is said to go at the natural speed limit, as soon as light cannot escape from the boundary of the decaying star, neither can anything else. 52 At this point, light from both the star and that hitting the field from the other sources cannot escape, thus a black hole is born. The Schwarzchild radius, as is became known, was only dependant on the mass of the star in question, and was proportional to it. For instance, if a star had a mass of five times that of our Sun, its’ Schwarzchild radius would be 15km. As soon as the collapsing star has shrunk beyond its’ Schwarzchild radius it is said to have passed its’ event horizon as no outside observations can be made into it. The photon-sphere however is the point when light is forced to orbit the star, but is not pulled into the event horizon. The point at which the star’s mass is entered is called singularity. This, in his equation, lay at the very center of the black hole, and is considered to center of its’ gravitational field. The singularity is infinitesimally small because mathematically it is found to be a single point. As all stars are known to rotate, it is almost impossible that we would be able to find an example of the Schwarzchild black hole in nature. An Australian mathematician named Roy P. Kerr only discovered the relative equations to this fact in 1963. 53 He found them accidentally while working on another problem, and found that although the spinning black hole held resemblances to the Schwarzchild model, there were also distinct differences. In this new type of black hole, a body that enters it would be forced to move in a spinning motion down towards the singularity like water in a plughole. The limit at which light can still escape this dragging force is known as stationary limit. The momentum of the spin decreases the size of the event horizon, the limit between this and the stationary limit being the Ergosphere. 54 On a theoretical level, a body traveling faster than the speed of light within the Ergosphere could escape it, yet there is no escape from being dragged around within it. The Ergosphere is thought to produce an oval shape, being in contact with the poles of the event horizon, while on the equator having double the diameter of the event horizon.
It is mathematically possible that the speed of the spin of a black hole could cause the shrinking of the event horizon such that it disappears and the singularity is left on view. This would cause a naked singularity. This would not display the usual gravitational traits of a black hole and would be possible to blunder into without any previous warning. 55 It also carries the implication that we could potentially travel freely in and out of singularity, as the event horizon is no longer present. If this were the case, by going into the orbit of a naked singularity, time travel into the past could occur. In general, this is conceived to be an impossible situation, as black hole properties are assume by the size of the mass alone, with the charge and spin having little effect. These Kerr black holes would have a singularity that takes form of a ring. It’s singularity is not space-like as demonstrated in the other model, but time-like instead. Only objects that enter the event horizon on its equator would be subject to destruction via the singularity. The interior of the singularity is an area of negative pace-time, implying the reversal of the force of gravity at this point. Another possible concept is that of objects within this plain having a negative radius, but no one has yet been able to fathom this idea rationally.
It has also been suggested that other black holes were created when the Big Bang occurred. These black holes were tiny, some as little as .0000001kg. 56 We know that the density of matter as it crosses the event horizon varies inversely to the mass of the black hole such that the black holes of this miniscule nature must have had enormous pressures applied to create them. These pressures were only thought to exist during the creation of the universe, as we know it. There is no evidence of their existence except for in the laws of quantum mechanics. Hawking that these black holes could have evaporated has put it forward. 57 It is known that the components of particles can be split to particles and antiparticles. When this occurs and the pair re-meet, they annihilate each other, and energy is created. Similarly, energy can be converted into pairs of particles. This is known as pair production, and only works because mass and energy are equivalent. Taking this idea further, matter can be created from for very brief periods of time. As it occurs almost simultaneously, it does not violate the conversation laws. If this occurred near to a black hole, and half of the pair was to fall into it, the inevitable annihilation should not occur. The other half of the pair would be able to escape. Energy is created. This energy has to have a notable source, as energy cannot be created or lost. 58 The source of such energy is the black hole itself. As it is robbed of energy, it is also robbed of its equivalent mass, thus the black hole evaporates due to pair production. This event would only have a noticeable consequence on the smallest of the black holes. If this process did occur, we would expect to see occasional bursts of gamma radiation being emitted from these mini black holes. As we obviously cannot see black holes, the only thing we can do to ascertain their existence is applying theoretical knowledge and observe the things that we suspect they cause. Detection of black holes is most likely to occur when we find an invisible object that has a mass, which could only possibly demonstrate one. Even then, we are working on the assumption that white dwarfs and neutron stars are unable to survive at such a mass. One way of calculating the mass of an object we cannot see is to follow the orbit around of a companion star. 59 If this star is found to be part of a binary system, with an invisible partner, then the mass of the companion can be calculated via spectral and visual analysis. If this mass is found to be in excess of 3 solar masses, then a black hole is presumed to have been found. Another way is by examining the matter that they pull toward themselves. This matter forms an accretion disk, which due to forces acting upon it, become hot enough to emit x-rays. These in turn can be detected and provide us with information on the fields acting upon them.
A black hole is said to encompass the four dimensions of space and time, thus as a body approaches the event horizon, time is distorted due to the force of acceleration, and force of the field. 60 To an outside observer, it would slow gradually, and along with it, the wavelengths, although maintaining velocity is shifted. As the body becomes even closer to the event horizon, time appears to stop. Strong tidal forces would cause the body to be ripped apart. Upon reaching the event horizon, the body would never be seen again, and is thought by scientists to race irreversibly towards the singularity, and become infinitely denser. 61 Although black holes have never been seen as such, their effect on the surroundings is clear. Thus by a principle called Occam’s Razor, the explanation of any phenomenon that requires the fewest arbitrary assumptions is the most likely to be the correct one. We assume that black holes exist, and continue to make their own individual mark in the universe we live in.
In the future, black holes could be greatly advantageous to us. Only, it would be extremely difficult to tap their immeasurable power. One technological advance black holes could help us achieve is time travel. Most scientists say that constructing a time machine is impossible, but time travel is not against the laws of physics. And, black holes could be the key to this. Physicists have speculated the existence of wormholes since the 1930’s. 62 These are gateways between different parts of the universe. Linking a pair of black holes makes one. By doing this, a tunnel is created through time and space. If you traveled through one end, and exited out the other, you would be in a different time and place. The only difficulty in this is trying to keep the wormhole from closing while the traveler goes through. If it were to close, the traveler would not be able to survive to make to the other end. Also, scientists have thought that it would physically impossible to travel through the wormhole. 63 One way it could be done is to use some sort of material capable of withstanding the great forces present. Even so, if we were able to do that, the time machine would have very limited ability. You could not go back to a time when the wormhole has not been created yet. We would also have to live in a society where we have already exploited the energy of black holes. All of this seems very, very difficult – but not impossible. Something else, which could be beneficial to us, is if we could harness the energy of a black hole. An entire civilization (technologically advanced) could gather enough energy from it to fulfill all of its power requirements. We would have to build a structure that could withstand the immense gravitational forces around the event horizon. It would collect energy from the black hole, but energy taken this way would not be unlimited. In the future, I believe that black holes will be more beneficial to us than threatening. Although the nearest black hole to us is fifteen light years away it would be easier to take advantage of it than have it pose any threat to us. Also, the most super massive black holes are confined to the centers of very distant galaxies. The only way a black hole could do anything bad to us is if we somehow gained access to one in the future, and an accident occurred. What if the black hole were our only power source and something were to go wrong? What would we do? Maybe black hole technology would fall into the wrong hands. If we were able to make something useful out of a black hole in the future, is it possible for someone to create a destructive weapon out of one? Still, I believe that if we could gain access to a black hole, it would be much more useful than harmful to us.
Black holes do not live forever, and as stars, they die. Theories of what happens when black holes die are just speculations. The theory of black hole evaporation is the most popular one. Black holes emit radiation, and the energy to emit this radiation comes from the black hole's mass, thus shrinking the black hole. Gradually, a black hole wears itself out into nothing. Black holes are still very mysterious things. Nobody can go into a black hole or even get near it to do studies, and it is unlikely anyone will anytime soon. Right now everything we know about black holes could be wrong. Maybe one day we will be able to send satellites into black holes, but for now we will only be able to make more theories about these powerful mysteries. Black holes are filled with many natural phenomenon’s’ gravity crushes and form it. Light makes them so unusual, and stars begin the life of a black hole by the death of their own. When combined together these factors create black holes in our universe. No one knows what black holes really are, and they are rarely thought of ever existing. Since they emit no light no one has ever seen one, and in order to observe them you must look at gravitation of nearby matter. Black holes are amazing and intriguing, and although they are not the unproven phenomenon of wormholes they are still out of this world. In conclusion, black holes are not theoretical (as they once were) but are a reality. Most of the aspects of black holes seem bad or threatening when first looked at, but it is possible they can be very beneficial to us in the future if we could gain access to one. Time travel, which is not impossible, can be accessible to us using black holes, although it might not be very beneficial if we do not know how to travel correctly. Finally, the fact that they could provide us with enough energy to fuel an entire society is also very beneficial.
Endnotes
1. Paul Strathern. Hawking and Black Holes. (London: Anchor Books Doubleday, 1988), 56
2. Strathern, 63
3. Gerald Cecil. “The Structure of the Black Holes.” Scientific American
December 1994, 70.
4. Chris Miller. “Black Holes,” The structure of a black hole. 30 September 1998,
http://www.eclipse.net/~cmmiller/BH/blkbh.html (March 15, 2002).
5. Cecil, 70
6. Cecil, 72
7. Stephen. Hawking. A Brief History of Time. (London: Bantam Books, 1996), 80.
8. Hawking, 90
9. Jillian. “Jillian Guide to Black holes: Finding ‘em.” Black Holes by Supernova.
15 June 1988
forming.html. (March 15, 2002).
10. Jillian. “Jillian Guide to Black holes: Finding ‘em.” Black Holes by Supernova.
15 June 1988
forming.html. (March 15, 2002).
11. Timothy Ferris. “The Scietific American Book of Astronomy. (New York: The Lyons Press, 1999), 120
12. Ferris, 122
13. Bruce Gregory, Paul Halpern. The Structure of the Universe. (Henry HoH and Company 1997), 225.
14. Jillian Guide to Black holes: Finding ‘em.” Black Holes. 14 June, 1999,
(April 14, 2002.)
15. Jillian Guide to Black holes: Finding ‘em.” Black Holes. 14 June, 1999,
(April 14, 2002.)
16. Jillian. “Jillian Guide to Black holes: Finding ‘em.” What is Singularity? 15 June 1998,
(March 15, 2002).
17. Jillian. “Jillian Guide to Black holes: Finding ‘em.” What is Singularity? 15 June 1998,
18. Jillian. “Jillian Guide to Black holes: Finding ‘em.” Accretion Disks. 15 June 1998,
(March 15, 2002.)
19. Jillian. “Jillian Guide to Black holes: Finding ‘em.” Accretion Disks. 15 June 1998,
(March 15, 2002.)
20. Jillian. “Jillian Guide to Black holes: Finding ‘em.” Accretion Disks. 15 June 1998,
(March 15, 2002.)
21. Paul G. Hewitt, John Suchocki, and Leslie A. Hewitt. Conceptual Physical Science. (New York: HarperCollins, 1994), 501.
22. Hewitt, 505
23. Hewitt, 515
24. Eric Chaisson. Relatively Speaking: Relativity, Black Holes, and the Fate of the
Universe. (New York: W.W. Norton & Company, 1988), 515.
25. Chaisson, 77
26. Chaisson, 77
27. Chaisson, 19
28. Chaisson, 77
29. Chaisson, 195
30. Hawking, Stephen. A Brief History of Time: From the Big Bang to Black Holes. (New York: Bantam Books, 1988), 82.
31. Hawking, 82
32. Ted Bunn. “Black Holes FAQ.” NSF Science and Technology Center September 1995, (February 20, 2002).
33. Hawkings, 86.
34. Hawkings, 86.
35. Hawkings, 86.
36. Hawkings, 22.
37. Hawkings, 49.
38. Hawkings, 88
39. Bunn, Ted “Black Holes FAQ.” NSF Science and Technology Center, September 1995,(February 20, 2002).
40. Bunn, Ted “Black Holes FAQ.” NSF Science and Technology Center September 1995,(February 20, 2002).
41. Bunn, Ted “Black Holes FAQ.” NSF Science and Technology Center September 1995,(February 20, 2002).
42. Bunn, Ted “Black Holes FAQ.” NSF Science and Technology Center September 1995,(February 20, 2002).
43. Bunn, Ted “Black Holes FAQ.” NSF Science and Technology Center September 1995,(February 20, 2002).
44. Bunn, Ted “Black Holes FAQ.” NSF Science and Technology Center September 1995,(February 20, 2002).
45. Bunn, Ted “Black Holes FAQ.” NSF Science and Technology Center September 1995,(February 20, 2002).
46. Bunn, Ted “Black Holes FAQ.” NSF Science and Technology Center September 1995,(February 20, 2002).
47. Pickover, Clifford A. Black Holes: A Traveler’s Guide. (New York: John Wiley & Sons, Inc., 1996), 4.
48. Pickover, Clifford A. Black Holes: A Traveler’s Guide. (New York: John Wiley & Sons, Inc., 1996), 4.
49. Pickover, Clifford A. Black Holes: A Traveler’s Guide. (New York: John Wiley & Sons, Inc., 1996), 5
50. Pickover, Clifford A. Black Holes: A Traveler’s Guide. (New York: John Wiley & Sons, Inc., 1996), 5.
51. Pickover, Clifford A. Black Holes: A Traveler’s Guide. (New York: John Wiley & Sons, Inc., 1996), 5.
52. Pickover, Clifford A. Black Holes: A Traveler’s Guide. (New York: John Wiley & Sons, Inc., 1996), 6.
53. Pickover, Clifford A. Black Holes: A Traveler’s Guide. (New York: John Wiley & Sons, Inc., 1996), 6
54. Pickover, Clifford A. Black Holes: A Traveler’s Guide. (New York: John Wiley & Sons, Inc., 1996), 6
55. Pickover, Clifford A. Black Holes: A Traveler’s Guide. (New York: John Wiley & Sons, Inc., 1996), 6
56. Sylvain Smith. “Particles of the Black Holes.” Astronomy. (December 1995), 15.
57. Smith, 16
58. Kate Wang. “Star Mass.” Scientific American. (March 12, 1995), 57.
59. Sagan, Carl. A Brief History of time from The Big Bang to Black Holes. (London: Bantam Books 1988), 120.
60. Stephen Hawkings. A Brief History of Time. (London: Bantam Books, 1996), 500.
61. Taylor, John. Black Holes: The End of the Universe? (London: King’s College, 1973), 1050.
62. Robert H. Hazen, Maxine Singer. Why aren’t Black Hole black? (New York: Anchor Books Doubleday, 1997), 5000.
63. Kitty Ferguson. Prisons of light: Black Holes. (New York: Cambridge University Press, 1996), 4060.
Work Cited
Bunn, Ted “Black Holes FAQ.” NSF Science and Technology Center September 1995,
February 20, 2002.
Cecil, Gerald. “The Structure of the Black Holes”. Scientific American. December 1994, 71-72.
Chaisson, Eric. Relatively Speaking: Relativity, Black Holes, and the Fate of the
Universe. New York: W.W. Norton & Company, 1988.
Ferguson, Kitty. Prisons of light: Black Holes. New York: Cambridge University Press,
1996.
Ferris, Timothy. “The Scietific American Book of Astronomy. New York: The Lyons Press, 1999.
Gregory, Bruce, Halpern, Paul. The Structure of the Universe.. Henry HoH and Company 1997.
Hawking, Stephen. A Brief History of Time: From the Big Bang to Black Holes. New ` York: Bantam Books, 1988.
Hawking, Stephen. A Brief History of Time. London: Bantam Books, 1996.
Hewitt, Paul G., John Suchocki, and Leslie A. Hewitt. Conceptual Physical Science. New York: HarperCollins, 1994.
Hazen, Robert H, Singer, Maxine. Why aren’t Black Hole black? New York: Anchor Books Doubleday, 1997.
Jillian. “Jillian Guide to Black holes: Finding ‘em.” Black Holes. 14 June, 1999.
April 14, 2002.
Jillian. “Jillian Guide to Black holes: Finding ‘em.” Accretion Disks. 15 June 1998
March 15, 2002.
Jillian. “Jillian Guide to Black holes: Finding ‘em.” What is Singularity? 15 June 1998
(March 15, 2002).
Jillian. “Jillian Guide to Black holes: Finding ‘em.” Black Holes by Supernova.
15 June 1988
forming.html. (March 15, 2002).
Miller, Christopher “Black Holes,” The Structure of A Black Hole. 30 September 1998,
http://www.eclipse.net/~cmmiller/BH/blkbh.html (March 15, 2002).
Pickover, Clifford A. Black Holes: A Traveler’s Guide. New York: John Wiley & Sons, Inc., 1996.
Sagan, Carl. A Brief History of time from The Big Bang to Black Holes. London: Bantam Books 1988.
Smith, Sylvain. “Particles of the Black Holes.” Astronomy. December 1995, 15.
Strathern, Paul. Hawking and Black Holes. London: Anchor Books Doubleday, 1988.
Taylor, John. Black Holes: The End of the Universe? London: King’s College, 1973.
Wang, Kate. “Star Mass.” Scientific American. March 12, 1995, 57-59.
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