Главная > Реферат >Остальные работы
Use Of Black Holes In Space Transit System Essay, Research Paper
1. Theory of Black Holes
Black holes are one of the least understood phenomenons in the galaxy yet the secrets contained within the black hole could revolutionize the field of physics. Black holes are formed when an enormously massive star, most likely a neutron star, collapses in on itself. This happens because when the star dies all the energy generated from the sun s fusion reaction that was formerly pushing outward suddenly stops. When the outward force stops, the sun has so much mass that its own gravity collapses the star into a black hole.
This only happens naturally with extremely massive stars because it needs enough force pulling inwards from the gravity to break the strong and weak forces in an atom. The mass can then compress to less than a millionth of its previous size because most of the space in an atom or molecule is empty. When this happens a singularity is formed, this is the incredible massive center of a black hole.
2. Schwarzschild Radius
When a star collapses its mass determines what radius the black hole will have. This radius called the Schwarzschild radius and is given by:
r=2GM/c2 (O Neill, 138)
Where r is the Schwarzschild radius, G is the gravity on the surface of the star, M is the mass of the star, and c is the speed of light. As particles approach this radius they are accelerated toward the speed of light. Because of this phenomenon, even light that gets caught in the gravitational spiral of a black hole cannot escape.
3. Time Dilation
This leads us into the idea of time dilation, the phenomenon that time appears to slow down as one approaches the speed of light in the outer spiral of a black hole. Relativity gives that as any object gets closer to the speed of light, time in their field of reference is the same but to anyone moving slower than them, their time appears to grow infinitely slow. That is, if a person where to go toward a black hole, when they entered the spiral particle cloud surrounding a black hole it would appear to a person on earth as if they were stopped. In fact, a person on earth would never see that person reach to center of a black hole because the light that would be required to see him would itself never be able to escape the black hole. If the light were never able to leave the black hole you could never see him enter the black hole.
This phenomenon would not last forever though, because black holes evaporate because of mass lost through a process to be discussed in part 4. Therefore the person standing on earth would see the person flying into the black hole actually enter the black hole a faction of a second before the black hole finally evaporated. At which point it is unknown what might happen, when the final remaining energy would explode or if all the energy would be expended and the black hole would vanish.
4. Kerr Black Hole
It is important now to distinguish between two types of Black Holes, non-rotating black holes and rotating Kerr Black Holes. Kerr Black Holes are the only type to be considered in this paper as they offer different properties and opportunities for energy collection than the basic non-rotating Black Hole. A Kerr Black Hole has a Schwarzschild radius encompassed by a rotating spiral of matter and energy destined to enter the black hole. Black Holes can rotate at varying velocities and as the rotational velocity increases the spiral becomes more violent and the Schwarzschild radius disappears into a type of funnel, which leads to the singularity. This is a very complex idea in that this funnel does not occupy any area in normal space, it is in fact a point where space bends around the black hole, creating a pocket in space accessible only through the black hole.
It is my theory that a black hole with this property could become linked with its opposite, a white hole and this would create a wormhole. Therefore as energy or matter is drawn into the black hole by the singularity, it would travel through this funnel and before reaching the crushing gravity of the inner singularity it would be pushed out the exit point of a white hole. A black hole and white hole are perfect opposites as described by the equations for relativity. A black hole can only pull matter or energy in, and a white hole can only expel matter or energy. The effect of a funnel traveling through curved space before reaching the event horizon gives the possibility that this funnel could reach to any point in space because this funnel s length is not relative to the distance it covers in normal space. Therefore, because of the potential energy resources of a black hole and the potential for shortcuts through space I believe that black holes could be used as a self-sustaining transit system trough space.
II. Possible Energy Sources in Black Holes
1. Three most probable energy sources
There have been many different approaches taken by science fiction to theorize on the possibility of obtaining energy from a black hole. The three that have the most conventional possibility of success are the extraction of energy from rotation, particle emission, and mass.
2. Rotational Energy
When a star collapses into a black hole it retains 99% of the original energy it had at the time of its creation. This also includes the rotational energy build up over time. When a star is born, it doesn t magically start spinning in place, the normal rotation of a star is slowly increased by gravity fields pulling it in different directions. Even forces that perceivably have no effect like that of a comet all have a cumulative effect in rotating the star. Over billions of years of small tugs in one direction or another the star builds up a rotational velocity, which can be tapped because its magnetic field rotates as it does.
Therefore because a black hole would retain this rotational energy at the time of implosion it is possible to use this energy. Because of the much reduced size and infinitely increased gravitational force it would be possible to construct around a black hole a type of generator. The generator would be comprised of two rings. The outer ring would be positioned outside the intense gravity well while the second ring would be positioned just outside of the event horizon.
The inner ring would be attached to the outer ring with a series of cross braces that would have to be melted into the structure of the inner ring. This is because just outside the event horizon the gravitational pull is so strong that a standard weld may not be sufficient attachment. When the immense rotating gravity well catches hold of the ring the struts that attach it may be torn lose because of the acceleration it would undergo. This is because of the amount of angular momentum stored in a black hole which is found by the equation.
(O Neill, 194)
The physical value of J for a star like the sun is: J=1.63 x 1048 gcm2/s corresponding to a=0.185 M. The intense gravity field around a black hole warps space and in fact the inner ring will feel no frictional force once it has reached the same angular velocity of the black hole because the space in which it resides is also being warped and rotated around the black hole.
3. Other Possibilities
Another possibility in the extraction of rotational energy is to create another black hole, although I do not pertain to understand how to accomplish this. This second black hole need not be very large because all its mass will be supplied by the larger black hole once it is created. The idea is to place this second black hole adjacent to the event horizon of the first so that the two horizons merge, at this point the turbulence created would follow the rules of fluid dynamics, in that case a generator could be placed at the mouth of this turbulence and the resultant eddies would provide the energy. Since the particles at the event horizon are accelerated near the speed of light, the resultant energy that could be produced would be enormous.
4. Mass Energy
The energy stored in the mass of a black hole is the greatest storehouse of energy in the universe. During the time of a stars billion-year life it loses 1% of its energy and when the star becomes a black hole all the energy is retained. The problem is that all this energy is held between the atoms in the attractive and repulsive forces. When a star collapses in on itself it is because the gravity overpowers those forces, but because certain transformations are possible in black holes it may become practical to use this energy.
First, it may be possible due to certain implications of fluid mechanics and the structure of a black hole to use a second black hole to pull mass away from a larger primary black hole. This is possible because an infinitely small black hole has the same pull on any object as does a black hole the size of the galaxy. The only difference is the distance this pull can affect. The black hole to be used must be a small black hole because it is necessary to avoid bending as much space around the black hole as possible.
This may need some explaining, so imagine a whirlpool, with the water swirling around and spiraling into the whirlpool s center. This is like a black hole except, once a black hole becomes massive enough, space is distorted so violently that neither mass nor energy can escape once caught in the spiral. In a smaller black hole, space is only slightly curved around the black hole until it reaches the event horizon, at which point the two black holes function identically. This is also applicable to varying rotation velocities, the higher the velocity at which a black hole spins, the more violent is the spiral and the faster and more violently space is distorted by the black hole.
Therefore, once a suitable candidate black hole is found, one with a relatively low rotation velocity and large area, a smaller black hole is positioned in space at a point where the outer range of the secondary black hole s gravity crosses into the outer ring of the primary black hole s spiral. This would provide the perfect setting for a magnetic generator because the ensuing eddies created by the turbulence of the two combined event horizons would function like two counter rotating vortices. This creates a standing whirlpool at the point of combination with zero inward force but enormous force along the edges of the vortex. At the center of this vortex then, it would be possible to place a magnetic generator designed with two counter-rotating cylinders. The outer cylinder would use scoops extended from the body of the cylinder like a paddle wheel. This would spin the outer cylinder and the inner cylinder can be spun in the opposite direction by feeding off the same paddle wheel with simple set of gears. This generator would be able to make more energy than any modern power plant because the magnetic fields in the cylinders can be kept at enormous levels by using the obtained energy to sustain the electromagnetic fields.
This leads into the final area of the paper and perhaps the most important. The study of what science fiction has long termed wormholes, actually called Einstein-Rosen Bridges is a highly controversial point because as of yet no empirical evidence has arisen to substantiate this idea made by Einstein decades ago. But the equations of general relativity have shown a possible way for a wormhole to exist without our necessarily being able to detect it at all. This is by the creation of a white hole. This is the absolute opposite of a black hole. Wormholes could function as a possible route of transit through the universe. The problem is that in order to traverse an Einstein-Rosen bridge from one universe to the other, a traveler would have to move faster than light at some stage of the journey. And there is another problem with this kind of wormhole — it is unstable. Surprising though, the Schwarzschild geometry shows when you shrink the mass to its Schwarzschild radius, you don’t get a bottomless pit; instead, the bottom of the diagram reopens to connect with another area of flat space-time. But the wormhole doesn t exist long enough for light to cross the threshold.
II. Sustaining a wormhole through a Kerr Black Hole
Intriguingly enough though, add either electric charge or rotation to a black hole, and you create a Kerr black hole. This transforms the nature of the singularity, thereby creating a wormhole where the journey is possible at less than the speed of light. This change is made possible because adding electric charge to a Kerr black hole provides it with a second field of force, in addition to gravity. Because charges with the same sign repel one another, this electric field acts in the opposite sense to gravity.
Although gravity still tries to slam shut the door opening to other universes, the electric field, or rotation, holds the door open for travelers to get through. But it is still a one-way door; you could not return to the region you started from. What goes in one end (the black hole) comes out of the other end (the white hole). Return to you point of origin would require a separate doorway.
Also, the calculations suggest that the attempted passage of a spaceship through the hole should cause the wormhole to slam shut. The problem is that an accelerating object, according to the general theory of relativity, generates ripples in the fabric of space-time itself known as gravitational waves. Gravitational radiation itself, traveling ahead of the spaceship and into the black hole, would amplify to infinite energy as it approaches the black hole singularity, thereby warping space-time around itself and closing the portal on the accelerating spaceship.
However, there is an interior tunnel in the Kerr solution of the Einstein Field Equations, but it’s unstable. The slightest perturbation would seal it off and convert the tunnel into a physical singularity through which nothing can pass. To prevent this collapse, the interior of the wormhole would have to be constantly monitored and controlled. It could operate by a process known as negative feedback, in which any disturbance in the space-time structure of the wormhole would cause the creation of another disturbance, which would cancel the first. This is the opposite of the familiar positive feedback effect, which leads to the howl from loudspeakers when a microphone, which is connected in to a speaker through an amplifier and is then placed in front of it. In that case, the noise from the speakers goes into the microphone, gets amplified, comes out louder than before, gets amplified, etc… In negative feedback, a computer would analyze the noise traveling from the speakers to the microphone and produce a sound wave with the opposite characteristics from another speaker. The two waves would then destroy one another, producing total silence (Wald, 98). This principle could build a system that sits in the throat of a wormhole and can record the oncoming disturbances. It would then transmit a series of gravitational waves that would cancel out the disturbances before they destroy the wormhole.
III. Maintaining stability inside the Wormhole
Morris and Thorne attempted in the 1990 s to determine how wormholes were created. Instead of considering some known object in the Universe they started out by constructing the mathematical description of a geometry that described a traversable wormhole, and then used the equations of the general theory of relativity to work out what kinds of matter and energy would be associated with such a space-time(Thorne, 18). They found that gravity tends to create singularities and close off the mouth of a wormhole. Their equations surmised that in order for an artificial wormhole to stay open, something must thread the funnel mouth that exerts negative pressure.
The conceptual idea of anti-gravity was first discovered as long ago as 1948 by Caismir. The basis of the Caismir effect is shown better two metal plates places slightly apart and parallel. The quantum between the plates seethes with activity of atoms colliding and light refracting. But the activity within the boundaries of the plates was consistently found to be less than that outside them. As Casimir pointed out, this occurs because electromagnetic waves would only be able to form certain stable patterns. Waves bouncing between the two plates would act like the waves on a plucked guitar string. Such a string can only vibrate in certain ways, to make certain notes. The allowed vibrations are the fundamental notes for a length of string, and its overtones. In the same way, only certain wavelengths of radiation can fit into the gap between the two plates of a Casimir experiment. In particular, no photon corresponding to a wavelength greater than the separation between the plates can fit in to the gap(Wald, 157).
It may be possible to construct a self-sustaining transit system through wormholes by use of all the ideas posed here. This system would utilize an advanced form of the Casimir effect by use of magnetic fields wrapped around the wormhole instead of solid metal plates. This would stabilize the tunnel of the wormhole and to stabilize the openings the proposed used of negative feedback should be used and incorporated into a small space station in the interior of the wormhole, thus allowing the constant monitoring of the waves being generated. These two stabilizing machines would consume massive amounts of energy, which is why the most practical energy sources of a black hole were posed and should be used to power this inner array of devices. This would allow for an almost limitless amount of time the wormhole could be safely used, as the system would not exhaust its energy supply for many thousands of years. The only down side to using a wormhole made in a black hole is that a wormhole like this is only one way, because of the nature of black holes and white holes it would be necessary to find another black hole for the return journey or hope you never have to come back because a black hole can effectively tunnel through space, connecting regions that appear to be far away because of the curvature of space.
- ... and functions in certain traditions. In addition, black holes influence the intergalactic space as ... exceeding the speed of light. The presence of black holes contains certain attributes ... appears purely black on all readings even through the use of radiation ...
- ... of relativity predicted in 1915 Schwartzschild singularities. In 1967, these were renamed black holes. A black ... of black holes. By doing this, a tunnel is created through time and space. ... done is to use some sort of material capable of withstanding the ...
- ... is impossible to use the laws of physics to predict ... seen in space. At this exact point in time, high amounts of radiation ... the mass of two suns or greater can form black holes in the ... appears purely black on all readings, even through the use of radiation ...
- ... go in one? Black holes are the mysterious dark regions of the universe. A black hole ... is an area of space made up of extremely ... maybe even be able to use them to our advantage and ...
- ... be seen in space. At this exact point in time, high amounts of radiation ... take an in depth look at black holes and the collapsing of stars, were ... appears purely black on all readings even through the use of radiation ... we will be able to use the universe to our ...