Science Fiction Project: "Emergence"

Property of PAN

 

Objective

This project will feature a short science fiction story using astronomy concepts based on the SAO unit 605, Theories of Space and Time. Following the story will be an evaluation of the story from a scientific viewpoint, explaining the concepts involved in the storyline, and determining how realistic the treatment was.

 

Emergence

Streaks of sunlight filled the hotel room where Erik was staying. Only yesterday he had attended the advanced theoretical physics seminar at CSA - Central Space Authority headquarters. There he had viewed the new sculpture on display. Titled "Emergence", the carved stone slab represented a space-suited astronaut flying into the heavens, to find his ancient tribal gods waiting. The scene had stayed on his mind. In the wee hours of the night, it had morphed into a disturbing dream. In a chaotic landscape of medieval images and megaliths, the old gods of his people had been calling for him to join them. In ancient Grianach, the land of his clan, a people named the Guineach were facing catastrophic events. Their cry had risen to the council of the gods who reside at the Pole Star. Across the ages they were calling to him. He must go, he must go...

 

Daylight found him in a cold sweat. As a Druid, Erik understood that dreams had meaning. Unable to shake the sense of urgency that had come with the images, he stroked the gray whiskers of his beard, and made the most important decision of his life. He had heard the call. He was going back. His people, his ancient homeland, needed him. He must get to the bottom of the crisis that called him back in time.

 

For the past several years, the Edinburgh Academy for Advanced Sciences where he was employed had been constructing a prototype of a new machine, a time travel device based on the Einstein-Rosen bridge design. The device could open a microscopic wormhole tunnel from this point in time to a location in the past. The pressure differential would immediately suck in matter placed on the launch platform in front of the entrance point at superluminal speeds, converting the mass into tachyonic particles according to the well-known relationship between matter and energy, and depositing it as reconstituted matter out the other end of the tunnel. The device in theory was able to transmit the superluminal beam to a predetermined target. Preliminary tests had been successful, but as yet, no human had made the trip. It was risky. But hadn't he spent years assisting Rosenthal in the design? Yes, and all it needed now was a test drive. Carefully he packed a few pieces of equipment into his satchel. Grabbing a cloak, and the walking staff he had received upon initiation into the 19th Order of the Holy Keepers of the Electric Grove, he set off for Rosenthal's lab.

 

The application was swift and painless, with only a strange fluttering sensation as his molecules converted into faster-then-light tachyons and sped through time. He landed with a thump, and found himself sprawled in the cool morning dew of lush grass. Nearby as fate would have it, a young Guineach lad named Caileadair had been sitting, miserably pondering his fate. For several years, extraordinary events had been occurring, and with alarming frequency. Trees caught on fire before they were hit by lightening. A warrior fell in battle before the death-dealing blow was struck. On one occasion, a hut had even risen from a pile of lumber and constructed itself! Clearly evil spirits were at work. For weeks now, he had been coming to this sacred grove near the stone circle calling to the gods for aid. In the midst of this gloom, he had suddenly felt a prickling sensation. A wind of supernatural origin blew through the clearing. He had the distinct impression that the wind had passed straight through him! A swoosh, a whoosh, and with a static crack and a pop, before his very eyes, sprawled face down in the grass was the answer to his prayers - a wizard!

 

Suddenly aware of his surroundings, and that a stupefied young man sat staring at him with his mouth agape in disbelief, Erik stood, straightened his cloak, and proceeded to conceal his return trip ticket, the tachyonic controls which had a non-local string connection to the wormhole generator in the lab. These he stored at the base of a large holed megalith. Turning, he stiffly approached Caileadair. "You may rise lad". The youth lost no time in introducing himself and explaining his dilemma.

 

Erik listened gravely. It was fortunate that he was well versed in the ancient tongue. Under normal circumstances, this would be an incredible scientific achievement, and yet there was little time to reflect on this aspect of his journey. From the sounds of it, something dangerous and unusual was occurring in Grianach, but he doubted it was of supernatural origin. Events were happening out of sequence, against the arrow of time. Somehow, a basic and long accepted tenet of the universe was broken. Causality had been negated, and the phenomena appeared to be spreading. Left unchecked, could this disastrous rip in time proceed into the future affecting his own civilization?

 

Together the new comrades set off for a great ring of stones that the Guineach was attempting to erect. Using hemp ropes and pullies, the stones were slipping in the mud.

The stone crew, weary and dirty, were struggling in vain, except for the bizarre moment when one of the stones appeared to raise itself. Immediately, Erik knew what to do. Reaching for his satchel, he fumbled around for the GWM. The first Gravitronic Wave Modulator had been constructed in 2027, some years after the great gravitational wave detector LIGO XII had made the initial discovery of a 100 Hz frequency signal coming from a binary neutron star merger. The device enabled the direct negation of the gravitational waves generated by any particular mass, by effectively placing the object into a state equivalent to a local frame free-fall. "So help me, Alfred" Erik muttered as he slapped the small circuit chip of the GWM onto the rough surface of a stone. Slowly, the stone became weightless and rose several inches off the ground, then drifted away in accordance with the Earths spin. Gasps escaped from the workers, but Caileadair quickly urged them to move the stone in place. Methodically, Erik and stone crew worked along the wall, alternately levitating and setting the large blocks, until the barricade was complete.

 

Several weeks passed, during which Erik noted even more bizarre occurrences. But he was no closer to solving the mystery. Having a moment to himself in the falling twilight, he sought a quiet moment to return to the sacred grove near the megalithic circle. Here he erected a small shrine and began a simple ritual in the hopes of communicating with the old gods. Perhaps he could gain insight into his venture. As he began speaking the ancient words "Tagann feasa lastigh", the grove around him flooded with a misty blue light, whose source seemed to be the Pole Star Thuban. He became lightheaded and felt as if he was rising. Around him, one by one in the blue glow, faces were appearing. "It's the dream!" he whispered to himself, "the Emergence!" A face appeared directly before him and spoke, the words slightly out of phase with the moving lips.

 

"Greeetiiiings Erik, we've beeen waiting for youuu." Erik's mind filled with a thousand questions. "Oh mighty gods, spirits of my ancestors, you have sent for me and I have come." Yet as his eyes adjusted, he began to see details in the faces. A poignant pause followed. The old gods were speaking English. A nose became more defined here, eyes there...and with a shudder of recognition, Erik screamed, "It can't be! It can't possibly be! ROSENTHAL!" "Well yes" said Rosenthal, whose voice was coming in clearer now. "I believe you know my assistants." "...but....but" Erik sputtered, "how could you...?" Rosenthal was clearly amused. "Allow me to explain. A few years ago you see, I developed the first Feynman Reflector. The experiment was intended to prove whether the universe was open or closed, by sending both advanced and retarded energy waves through time, into the past and future of the universe. If the universe was closed, there should be a singularity at each end that could have bounced the waves back towards my own time. But, only the advanced wave bounced off the initial singularity from the Big Bang. My calculations were somewhat faulty at any rate, and the wave did not return to the present time. My present time, at the time, as it were. However, I had the foresight to also conduct the first mass to energy transfer, by sending two small negative energy transmitters along with each wave. The transmitter from the advanced wave, landed there. Precisely where we are having our eh, discussion. The small device is quite remarkable. It has the capability of directing a neutrino beam towards an energy source such as Thuban, and the unique ability to actually absorb energy rather then requiring energy. Having reached Thuban, the beam effectively siphons enough energy from the star to bounce back into the future at superluminal speeds and return to a similar device here in my lab. Hence, our conversation is possible."

 

Erik suspiciously eyed the grove, looking for the device. Rosenthal continued. "All of this of course, was quite top secret. Based on the results, we've been able to improve the technology in order to develop the wormhole bridge, which you've so wonderfully assisted with over the last several years. We've arranged your little venture through time, the whole scenario. We needed a human guinea pig you see. The final test phase of the Einstein-Rosen bridge is in our contract this year with CSA. Sorry for the subterfuge old man, but congratulations are in order, it's been a success. By the way, we need you back in the lab on Thursday. We're giving a press release at the Academy. I assume you know the way?" With a small blip, the communication ended.

 

A grass stain appeared on Erik's robe before he dropped to the ground in exasperation. His mind was spinning, taking in all that had transpired. He had been tricked, and yet he would have come willingly. He realized Rosenthal was completely unaware of the side effects his Reflector experiment had caused. He realized now what had occurred. Rosenthal's beam had traveled back in time, some 16 billion years to the initial singularity that produced the universe. In a normal condition of the universe, it was not possible to violate causality, as reverse time travel was not thought to be possible. Yet, here he was himself. Of course, his trip had been possible because the state of the universe had already been changed in the past. He surmised that the beam had traveled back to the Plank Epoch of the early universe, at a time of 10-43 seconds, when the four known forces, gravity, electromagnetic, and the weak and strong nuclear forces were still united. The beam left an imprint, which was magnified and carried through to the inflationary period. During that incredible moment, the universe had exceeded superluminal speeds by expanding by a factor of 1043 in roughly 1034 seconds. In the standard scenario, this should not have created tachyons the imaginary particle thought not to exist. Such particles could travel faster then light, so fast they go could travel backwards in time. The inflationary period of the universe should have happened at the speed of inflation, but Rosenthal's interference had caused tachyons to be produced at superluminal speeds at the same time. "Of course" he mused, that is how the wormhole bridge had worked. The problem now was that the natural evolution of the universe was altered in his past. This cosmic anomaly had been traveling through time into the future affecting mass and causing events to violate causality. He had to stop this from going any further.

 

Erik bid a hasty farewell to the Guineach, which was a pointless gesture, as they had begged him to stay before he mentioned he was leaving. He made his way to the megalith where he had buried his tachyonic tools. "In principle, this should be simple" he tried to convince himself. His intention was to alter the device, so that he could return to Rosenthal's lab, roughly five years prior to when he left. With any luck, he could arrive in time to stop the Feynman Reflector experiment from happening. But as he reached for the controls, the final irony occurred. Erik was transported before activating the device.

 

 

SCIENCE EVALUATION

Surely a tale fit for telling by the local Druid on a cold winters night down at the pub. But how feasible is it from a scientific standpoint? The following section will review key points from the story:

 

· Tachyons and superluminal speeds

· Mass and energy relationship

· Gravity

· Interstellar communication

· Quantum entanglement

· Negative energy

· Omega: end of the universe

· Einstein-Rosen wormhole

· Time travel, causality and paradoxes

 

 

Tachyons and Superluminal Speeds

Could there be a tachyonic time travel device? Faster then light ("FTL") travel, and possibly even time travel, is what the theoretical particles called tachyons are all about. While many physicists today dismiss tachyons as science fiction, they are a part of theoretical particle physics in the realm of quantum mechanics.

 

According to Einstein, a normal particle of matter (often called a tardyon, or bradyon for "slow") would not be able to accelerate to the speed of light because as its velocity increased, so would its mass. This would in turn require an infinite amount of energy in order to accelerate the mass, which would be physically impossible. On the other hand, the theory does not state that superluminal speed is impossible, only that a normal particle of matter cannot achieve it. This feat would need to be accomplished by a special particle, the tachyon. Using the relativistic equation ec2 = mc2/((1-v/c)2)1/2, and applying it to a superluminal particle, the velocity would be greater then the speed of light, with the result that the denominator becomes an imaginary number [1]. According to the equation, this also means that the mass of the particle at rest would also have to be imaginary [2]. In turn, having an imaginary mass means that the particle would not interact with normal matter, and would be unobservable.

Another trait of the tachyon, is that unlike normal matter which cannot accelerate to the speed of light, a tachyon would have the reverse situation in which it would be impossible for it to slow down to the speed of light. To do so would require an infinite amount of energy, which again is implausible.

 

If a superluminal tachyon beam were possible, it would travel faster then the speed of light, which in theory would imply that it could be used to travel backwards in time. For this reason, tachyon particles and superluminal speeds in general not only violate the order of causality, but also could create a paradox [3] which many physicists find difficult to reconcile. The by-product of this is that tachyons are often regarded as philosophical curiosities and consigned to the realm of science fiction, rather then mainstream science.

 

In other words, even if Erik had been able to transform himself into a superluminal tachyon beam, it could not have interacted with matter and the young lad in our story could not have felt it pass through him. On the other hand, if Erik had been traveling past the boy at a right angle while he was emitting light during his slow down from a tachyon beam to a speed of light velocity, the boy could have detected a small order relativistic Doppler effect as shown by [4]:

 

Doppler effect seen by observer = frequency of the beam √ ((1+β)/(1-β))

Where β = v/c.

 

But surely, this could not have occurred since the beam would require an infinite amount of energy to slow down. Now let's assume that a tachyon anomaly was created in the Big Bang. This would not violate Einstein's rule as the particle is neither accelerating nor decelerating, but was created at a superluminal speed. Such an anomaly would not be able to travel forward through time from the past, as space is isotropic and homogenous. The basis of the Inflation theory states that distant regions of space are the same, so the anomaly would not be able to exist at one locale, and not in another part of space. In this instance, the storyline is completely false. If the initial Big Bang had produced tachyons and had negated the principle of causality which was then spread throughout the universe with during inflation, it would exist both in Erik's future time, and in the past.

 

 

Energy and Mass relationship

According to Einstein's famous equation e=mc2, mass and energy are equivalent. In a reference frame with a particle at rest, e = m + k -> m + 0. In other words, the energy at rest is equal to the mass, Erest = m. If Erik were a speeding beam of particles with mass, his particles would have momenergy which would be proportional to its mass. The momenergy is independent of any reference frames, and would cause a space-time displacement in all 4 dimensions. By measuring the energy and momentum of the particles, one could prove that they also have mass using the equation below [5]. This would be a direct violation of a tachyon particle, as they would have to have imaginary mass.

 

m2 = e2 - (px)2 - (py)2 - (pz)2

 

Also according to Einstein, mass is not absolute. The faster an object travels near the speed of light, the more its mass will increase by 1/√(1-f2) [6].

 

The conclusion then is if Erik's particles were a superluminal beam of tachyons, they would have been massless, and unable to slow down. On the other hand if they had mass, they would have continually gained more mass during their speedy journey, gaining an infinite amount of mass nearing the speed of light. Hence, both scenarios are implausible. 

 

 

Interstellar Communication

Could interstellar communication be possible? How feasible would it be that the characters in the story could conduct a conversation in real time? Not very. For a one way trip to Thuban1, which is 309.2 ly away, with a time delay of as much as 1 year the signal would need to be traveling at the phenomenal speed of 309.2 times the speed of light.

 

velocity = distance/time

v= 309.2 ly / 1 yr

 

Traveling at the speed of light and allowing for time dilation, the distance as measured in the beam frame would be less then 309.2 ly. This would appear to the characters in the story as time dilation because at the speed of light or higher, time and space appear to contract, based on the formula [7]:

 

(interval)2 = (time separation)2 - (space separation)2

 

But even if a one way trip took as long as 1500 years for the signal to travel 309 ly at nearly the sped of light, the space-time interval, or in other words, the trip according to an imaginary clock in the beam frame would be less, at 1,467 yrs. A shorter trip yes, but this contraction of time is still not enough to make a real-time conversation possible.

 

Another obvious problem in this scenario would be the relative motions of the Earth and Thuban. If a beam was transmitted from the Earth directly at Thuban's location as it appears in the sky, it would of course miss the target due to stellar aberration. Likewise a return beam from Thuban to the Earth could not be seen to come directly from the star, as the position of the two would have have changed in relation to one another over time. 

 

 

Gravity

In 1916 Albert Einstein published the theory of General Relativity. Although he was not the first scientist to study the field, he was the first to propose an explanation for the origin of gravity, and explain it in a way that could account for some aspects long unresolved by Newtonian mechanics. While Newton had surmised that gravity was instantaneous action at a distance, he had failed to derive a suitable explanation as to why. In contrast, Einstein predicted that gravitational waves would travel at the speed of light and how they affected mass. In his equations, he modeled gravity on a tensor wave equation, which included a wave amplitude similar to those in electro-magnetic radiation [8]. His model predicted a propagating wave which would be transverse to the prorogation direction, have independent polarization, and would be as large as it's source [9]. Such waves would cause the space-time to vary through expansion or contraction, which would change the distance between two points according to an observer [10]. With this equation, one can see the relationship between mass and energy on the space-time [11]:

 

Rμv - 1/2gμvR     = Tμv

gravitational field = mass and energy

 

Although technically all objects with mass that are in motion produce gravitational waves, most waves are too small to be detected. While astronomical events exist along the order of black hole mergers and supernovas that would generate large waves, as yet even the higher magnitude waves have not been detected. However, a number of serious attempts are currently being conducted across the world to do so. The story mentions LIGO XII, which is a spoof on the ongoing Laser Interferometer Gravitational Wave Observatory I which has yet to detect a wave.

 

In regards to the storyline, Erik uses a device to counteract the Earth's gravitational acceleration of 9.8 m/-s. This means that at a distance of 1 meter at the surface of the Earth, an object would be attracted towards the gravitational center of the Earth at a rate of 9.8 meters per second. Erik's device would need to counteract this action. Gravity is by its nature weak, and humans counteract the effects of gravity on a daily basis just by moving around on the planet. According to Einstein, both active (walking around) and passive (gravitational acceleration) gravity are equal forms of gravitational mass [12]. So in this case, Erik could use a device that causes an upwards acceleration of an energy wave that could counteract the downward gravitational acceleration of 9.8 m/s. The two would cancel each other out, placing the stone into a state of free fall. Once in free fall, it's weight would become effectively zero, while it's mass would remain the same. This is because weight is a force, stated by Newton's Second Law:

 

weight = mass x gravitational acceleration.

 

If gravitational acceleration could be rendered to zero, then the weight of the stone would drop accordingly. Once in such a state, free from the gravitational attraction of the planet, the stone would be seen to drift. This is because the Earth itself is moving through space. With no forces to act on it the stone would stay in place while the Earth moved away from it.

 

Could an anti-gravity device be constructed at some point in the future? There is nothing in the theory of General Relativity that stops it. One must also consider that the most expensive science project of all time, NASA's Gravity Probe B was developed to detect gravitational waves. At a projected cost of over $600 million, one must speculate that if it was not theoretically possible to manipulate them once you found them, then why exert the effort [13]. As astronaut Jean Loup Chretien recently remarked to me on a recent trip to the Kennedy Space Center, understanding gravity is a primary aspect of future space exploration.

 

 

Quantum Entanglement

In quantum mechanics, an intriguing particle condition exists known as quantum entanglement. Literally, two particles separated by space are able to have a non-local string connection, where the events that happen to one particle of the pair instantly affects the other. If two particles were entangled at rest and boosted to near speed of light velocity they would remain entangled. Likewise, boosting a particle to such a velocity may also produce another particle seemingly out of nowhere, which is entangled to the original particle [14]. The distance between the particles can be vast, even across the universe. Einstein and his students Podolsky and Rosen introduced the concept in the EPR paradox (named for Einstein-Podolsky-Rosen) in 1935 as a thought experiment [15]. While their intent was to prove that quantum theory was incomplete because quantum entanglement was not possible, it led to a greater controversy and came into direct conflict with relativistic physics [16]. Einstein in particular disliked the idea of a non-local connection, calling it "spooky action at a distance" [17]. According to the principle of relativistic causality, casual influences cannot propagate faster then the speed of light, meaning events that have an inherent sequence of cause and effect cannot happen out of order, such as effect then cause. This certainly appears to apply to large-scale objects such as planes, trains, and automobiles, but in the quantum world at the atomic and subatomic level, quantum entanglement treads dangerously close to violating this premise.

 

In Erik's case, he has used a wormhole to transport himself through time from Rosenthal's lab to a point in the distant past. His intent was to rely on the quantum entanglement of the return controls which he has taken with him, in order to act as a directional guideline to return to the lab. By triggering the device on his end, the particles in the lab would activate the wormhole creating a gateway at each location of the entangled pair. Could this sort of particle relationship be possible? In spite of Einstein,

a news release by NASA's Jet Propulsion Laboratory in April 2003 announced that not only has quantum entanglement been achieved in a lab setting, but quantum teleportation and communication has also been proven experimentally [18]. While such devices may be decades away from becoming incorporated into modern technology, the science is feasible. While debates between proponents of quantum theory and relativistic physics continue to this day, it is generally conceded that quantum entanglement does not actually violate the principle of causality. In a way not yet understood, it may be that the influence between two entangled particles does not travel at a superluminal speed between the pair, but may be traveling a geodesic path through space-time, a curved path that is the shortest path between two points.

 

 

Omega: the end of the universe

In 1945, John Wheeler and Richard Feynman [19] proposed an idea called the Absorber Theory, where an electromagnetic event could produce waves like ripples on a pond flowing backwards and forwards into time [20]. One wave would flow backwards in time, and would eventually meet a wall of density produced by the Big Band, which would act like an absorber or reflector, reversing the waves direction and sending it back into the future. If the universe were closed, a similar wall of density may also exist at the other end of the universe.

 

In the story, Rosenthal explains to Erik that several years prior, he had conducted an experiment to determine if the universe was open or closed based on this theory. While it is unlikely that Rosenthal could have produced a wave of the magnitude needed to travel 13-16 billion years backwards in time to the Big Bang, the theory itself does pose an interesting thought experiment. In Rosenthal's case, he says he has detected the 'bounce' from the wave at the singularity at the beginning of the universe, but did not receive the evidence of a similar 'bounce' coming from the future, which he would have expected if the universe was closed, and had a Big Crunch event at the other end. Of course, his assumptions could be wrong in that the bounce may have not occurred yet, as the Big Crunch event may have been much farther out then the 13-16 billion years for the present age of the universe, and his beam may not have made contact yet.

 

According to General Relativity, the curvature of the universe is directly related to the amount of mass in the universe (both normal matter and dark matter) and as a result, predicts its eventual fate. This ratio of observed density (mass) to the critical density is known as Omega, the cosmic density parameter.  

 

· If Ω < 1 then the universe has a negative curvature, which means it has a hyperbolic geometry and is open. The universe will continue forever.

 

· If Ω = 1 then the universe is flat, and has an Euclidean geometry, and the universe has a critical density. The universe will expand to its maximum and then stay there. 

 

· If Ω > 1 then the universe is positively curved, and has a spherical geometry and is closed. The universe will eventually collapse in upon itself. 

 

Current estimates of Ω place it at a range at approximately .5 [21] up to 1 [22]. This would mean that our universe is likely either hyperbolic (saddle shaped) or flat. In either case, the results of Rosenthal's experiment are in line with current expectations.

 

 

Negative energy

In 1948 Hendrik B. G. Casimir derived what has come to be known as the Casimir Effect, the production of negative energy [23]. He found that by placing two uncharged metal plates together at extremely close distances, he was able to artificially produce a region of space (between the plates) that had a lower then average density then surrounding space. This is due to the fact that in a normal state, space is filled with particle-antiparticle pairs that continually form seemingly out of nowhere and then vanish [24]. By use of the plates in this case, normal space is squeezed to produce a type of vacuum, where fewer particles can be generated. As the total energy of normal space is positive, the area between the plates become negative [25]. This is sometimes referred to as Zero Point Energy (ZPE), although even in a negative energy vacuum state, there is always some amount of energy left over, so that it is impossible to have a truly zero energy condition [26].

 

In our storyline, Rosenthal states he has invented a device by which a negative energy beam is being used for communication over vast distances. The negative energy condition of the beam absorbs energy from an outside source (Thuban) in order to achieve the superluminal speeds necessary to transmit the two-way conversation back and forth in time. While that is stretching the concept a bit, negative energy does hold a great deal of potential for future technology. In recent years, NASA has researched the

possibility of using negative energy for future spacecraft propulsion systems, in projects such as the NASA Breakthrough Propulsion Physics (BPP) Project [27]. The basis of the project is that negative energy systems could provide an efficient energy source without needing a fuel supply. Unfortunately in January 2003 the current U.S. administration stopped funding for this promising area of research, so it may be many years yet before this technology comes to fruition.

 

 

Einstein-Rosen wormhole

In 1935 Einstein and Rosen came to realize that the precepts of General Relativity allowed for the concept of a bridge which could connect two regions of space and time [28].Their intention was not to propose a futuristic method of space travel, but was intended to explain the appearance and disappearance of particles by suggesting they could tunnel through space-time and reappear at different points in space. This bridge model can conceptually be described as a tunnel connecting two wormholes, a black hole that serves as the entrance, and a white hole that acts as the exit point. A wormhole in the theoretical sense would be able to not only connect different regions of space-time, but possibility even points in different space-times making time travel possible. 

 

Many physicists found the concept to be unnerving, in that causality might be violated should someone find a way to send a particle stream representing information back in time. For this reason wormholes were believed to be an unnatural state of the universe and if they existed at all, they would be unstable so as not to allow even a single particle to pass through. On the other hand, if a wormhole was unstable, it may be just as possible that entry could be made at a superluminal speed in order to make it all the way through before the tunnel could collapse.

 

Another problem with wormholes is that any mass within the hole would trigger its immediate collapse due to the generation of gravitational waves produced by the rapid movement of the mass. For this reason, physicist Stephen Hawking believes that although feasible, a wormhole could never be used to transport anything due to the mass issue [29]. He has also speculated that to create a wormhole on demand, a process would be required that could effectively reverse Einstein's space-time curvature, by curving it the opposite way. This would require negative mass and density, in order to counteract the normal positive mass and density of the universe.

 

While the existence of wormholes cannot yet be confirmed, our storyline takes these issues into consideration. Our Druid Erik has designed the wormhole in Edinburgh so that mass can be converted into a superluminal tachyon beam. This solves both problems, as tachyons have an imaginary mass so cannot generate gravitational waves, and by traveling at a superluminal speed through the unstable wormhole, he can quickly pass through before it can collapse. By traveling backwards in time however, he would appear to be violating causality...or does he?

 

 

Time travel, causality and paradoxes

The subject of time travel and causality brings us to our final topic, a review of the plausibility of time travel and the conflict with causality. First, let us clarify what causality is. The basis of causality states that we live in a time sequenced universe, where the result of an action follows the action itself. In this viewpoint, the arrow of time only flows one way, into the future. Time travel into the past would not be possible, because this could allow events to happen out of sequence. For example in the well known 'grandfather paradox', suppose a man could travel into the past to kill his own grandfather. If he was successful, would be himself disappear? Because of the nature of this paradox, many mainstream scientists today believe that time travel into the past would not be possible because the nature of the universe would not permit such such paradoxes to exist.

 

However reasonable this may seem, it is not an end to the argument. There have been several scientific examples in recent years regarding superluminal speeds, which by their nature would travel faster then the speed of light, to the extreme that they appear to travel backwards in time. In 1995, German scientist Günter Nimtz conducted an experiment where a microwave was used to transmit Mozart's 40th Symphony at 4.7 times the speed of light [30]. In 2000, Nature Magazine published the results of the work of scientist Lijun Wang of the NEC Institute whose experiment involved shooting a laser light pulse at a glass enclosed gas [31]. The results showed the gas reacted to the pulse 62 seconds before the laser had even reached the surrounding glass. These are incredible results. Even so most mainstream physicists maintain that such experiments do not violate causality, or constitute the transmission of information, hence Einstein's Special Theory of Relativity continues to remain intact.

 

On the other hand, there is the idea that should time travel be possible and our fictional hero Erik could travel into the past and alter events in such a way that they would change the future, the future as he knew it would itself instantly change to reflect these new variables. Let us combine the story and the grandfather paradox. Suppose Erik had raised a megalith in the distance past using scientific means, and that this stone would not have been raised otherwise. Now perhaps some years afterwards, this stone falls and lands on a child, who would have been the ancestor of a man would rescue Erik's father from a fire, in which he would have otherwise died before he procreated and produced Erik. By taking one mundane action in the past, Erik may irrevocably alter his own future by ultimately causing himself not to be born. In this scenario, there is but one universe that constantly adjusts to reflect new parameters. If this were the case, as soon as Erik had raised the megalith in the story he would have zapped out of existence.

 

Another possibility may lie in what is known as the Multi-verse theory [32]. In our tale, suppose that Erik has indeed traveled back in time, but not to his own past. In the Multi-verse theory, the universe exists as a probability wave matrix. For every action, a number of possible outcomes may exist, and correspondingly, a universe would exist in which every possible outcome had occurred. In this respect, time travel would be possible, but causality would be maintained, as the ensuing results of actions would always occur in a different universe so that it would not be possible to affect one's own future by traveling into their past.

 

 

IN CONCLUSION

To conclude this project, we will recap the various scientific aspects of our tale:

 

· Tachyons are theoretical particles with imaginary mass that travel faster then light and have the ability to travel backwards in time. They are not taken seriously by most scientists.

· Experiments continue with superluminal speeds, and some have produced intriguing results. However even if such speeds were confirmed, they do not constitute a violation of causality as information cannot be transmitted.

· The universe is isotropic and homogenous due to inflation, so an anomaly created at the time of the Big Bang such as the existence of tachyons could not exist in one section of the universe and not another.

· According to Einstein, mass and energy are equivalent. Energy can be found in many forms, and mass is one of those forms.

· The existence of gravitational waves was predicted by Einstein in his theory of General Relativity. They are likely to be a reality. Serious research is currently underway to prove this.

· According to Einstein, there is no difference between acceleration and gravity. In either case, the effects as observed within the frame would be indistinguishable.

· When traveling at a velocity near the speed of light, an object would appear to be contracted to observers as measured in an inertial reference frame.

· Time depends on the observer's motion. The exception to this is the speed of light which is the same in all frames.

· Quantum entanglement has been experimentally proven.

· The value of Omega is approximately .5 - 1, meaning that the universe is likely to be flat or hyperbolic.

· Negative energy exists, but has yet to be incorporated into mainstream technology.

· Wormholes are theoretically possible in that they may exist, but may not be usable for time travel.

· Time travel is theoretically possible but is largely dependent upon the infrastructure of the universe itself.

 

REFERENCES

[1] Albert Einstein: Relativity The Special and The General Theory. Random House, pp. 45-47 (1961).

[2] Chasing Tachyons.

http://www.physics.gmu.edu/~e-physics/bob/c.htm

[3] Cern Courier.

http://www.cerncour ier.com/main/article/42/3/13

[4] Relativistic Doppler Shift.

http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/reldop2.html#c1

[5] E. Taylor and J. Wheeler: Space-time Physics. W. H. Freeman and Company, pp. 195-197 (1992).

[6] Charles Sheffield: Borderlands of Science. Baen Books, p. 29 (2000)

[7] E. Taylor and J. Wheeler: Space-time Physics. W. H. Freeman and Company, pp. 102 (1992).

[8] Time Travel and Computing.

http://www.frc.ri.cmu.edu/~hpm/project.archive/general.articles/1991/TempComp.html

[9] Marcia Bartusiak: Unfinished Symphony. Joseph Henry Press, pp. 161 (2000).

[10] Time Travel and Computing.

http://www.frc.ri.cmu.edu/~hpm/project.archive/general.articles/1991/TempComp.html

[11] Marcia Bartusiak: Unfinished Symphony. Joseph Henry Press, pp. 44 (2000).

[12] Swinburne Astronomy Online: 605 Module 10.

http://astronomy.swin.edu.au/sao/

[13] NASA Orders Make-or-Break Tests for Gravity probe: Science, Vol 300, No. 5621, (2003).

[14] Charles Sheffield: Borderlands of Science. Baen Books, p. 27 (2000)

[15] A. Einstein, B. Podolsky and N. Rosen (1935).

[16] Wikipedia: Quantum Entanglement. http://www.wikipedia.org/wiki/Quantum_entanglement

[17] Charles Seife: Relativity Goes Where Einstein Sneered to Tread. Science, Vol 299, p.185 (2003).

[18] NASA Researchers Put New Spin on Einstein's Relativity Theory. NASA Jet Propulsion Laboratory.

http://www.jpl.nasa.gov/releases/2003/47.cfm

[19] Time Travel and Computing.

http://www.frc.ri.cmu.edu/~hpm/project.archive/general.articles/1991/TempComp.html

[20] Stanford Encyclopedia.

http://plato.stanford.edu/entries/causation-backwards/

[21] Swinburne Astronomy Online: Module 22.

http://astronomy.swin.edu.au/sao/

[22] Geometry of the Universe.

http://zebu.uoregon.edu/~js/ast123/lectures/lec16.html

[23] Casimir, H.G.B.: On the attraction between two perfectly conducting plates. Proc. Kon. Ned. Akad. van Weten., Vol. 51, No. 7, pp. 793-796.

[24] Gravitational Physics and Astrophysics: Casimir Effect.

http://www.sa.infn.it/GravitationAstrophysics/Casimir/Introduction.html

[25] Negative Energy, Wormholes and Warp Drive: Scientific American. (2000).

http://www.physics.hku.hk/~tboyce/sf/topics/wormhole/wormhole.html

[26] NASA: Vacuum Fluctuations of Quantum Physics.

http://www.grc.nasa.gov/WWW/PAO/html/warp/possible.htm#vac

[27] NASA Breakthrough Propulsion Physics (BPP) Project.

http://www.grc.nasa.gov/WWW/bpp/

[28] The Einstein-Rosen Bridge.

http://www.krioma.net/Articles/Bridge%20Theory/Einstein%20Rosen%20Bridge.htm

[29] Professor Stephen Hawking.

http://www.hawking.org.uk

[30] Science News Online.

http://www.sciencenews.org/20000610/fob7.asp

[31] Science Now.

http://sciencenow.sciencemag.org

[32] David Deutsh: The Structure of the Multiverse. (2001)

http://arxiv.org/ftp/quant-ph/papers/0104/0104033.pdf


1 Due to precession, the star Thuban in the constellation Draco would have been the pole star in 3000 bce which is the timeframe of the story at Grianach.