Near-light Speed

and Length

According to the theory of relativity, rods in motion contract in the direction of travel. A rod is any object in motion that extends parallel to the direction in which it is travelling. Though in theory we could imagine an object such as a spaceship or a flying saucer as being a rod, thinking of a rod as simply being a horizontal pole avoids unnecessary complication. When we say that such a rod 'contracts', we mean that the rod is observed to be shorter than its actual physical length, as a result of the speed of its state of motion. However, take note, rod contraction is noticable only when the rod is travelling at near-light speeds. The specific near-light speed at which the rod happens to be travelling, in turn, determines the degree to which the rod is observed to contract. This relationship can be successfully described by stating that the closer the rod's speed gets to the speed of light, the more contracted the rod will appear to be. In fact, if the rod were to reach light-speed, it would be perceived to have become so short that it would have no length! That is a property that all light-speed rods will be found to possess. What, then, is responsible for the occurrence of rod contraction? What is known for certain, firstly, is that the contraction that the rod is observed to undergo is not a physical contraction. Physically, the rod's length throughout the entire contraction process is never altered. All that is actually altered is the observer's perception of the rod. Let this information give one a clear glimpse as to the nature of the mechanics involved in the contraction of rods in motion.

Why do rods in motion contract in the direction of travel? Answering this question involves addressing all details of the contraction process. As the first step in doing so, we must ask a vital question: what does it mean to perceive an object? When we claim to "see" an object, what is really happening? It may be to your surprise that it's not the object that we are seeing, but rather its light: every object we perceive, you see, is the result of light leaving the object, travelling the distance from the object to your eye, and then physically entering your eye. Given this reasoning, it can be concluded that it is only until the light from an object has reached you that you actually "see" the object. Understanding this concept is the key factor involved in understanding why rods in motion are observed to contract. In summary, then, "seeing" an object is not an instantaneous occurrence - rather, it means being willing to wait for the duration of the period of time it takes for the light from the object to cross the distance in between the object and your eye.

Picture in your mind a stationary rod - a horizontal pole - nothing more and nothing less. The rod is located on the right side of your mental field of vision, putting its front (leftmost) tip nearest you. Imagine your head to be turned to the side, not having yet perceived the rod. Now view the rod. Because the front tip of the rod is closest, its light reaches us first. To document this arrival of light, place a brightly colored 'dot' on the front tip of the rod, signifying that it is now visible. It is for this first instant in viewing the rod that only the front tip of the rod is visible. In order for the light from the remainder of the rod behind the front tip to become visible, the light from those regions must first reach us. This doesn't happen "all at once", however, as one might think - it occurs piece by piece. To understand this, we must first realize that it takes time for the light from the regions behind the front tip to reach us, because they are farther away. The amount of time it takes for the light of any given region to reach us, take note, is dependent upon how far beyond the front tip of the rod the region is from us: the greater the distance beyond the front tip, the more time it will take for that light to reach us. The smaller the distance beyond the front tip, in turn, the sooner that light will reach us. As a result, the regions behind the front tip become visible to us sequentially - from left to right. To envision this process, recall the brightly colored dot on the front tip of the rod that we encountered above. Imagine this dot to begin moving across the length of the rod to its right, leaving a 'bar' of its own color behind. This growing bar represents the precise manner in which the light from the rest of the rod behind the front tip reaches us. As the bar glides to the right at a constant rate, we imagine the light from the regions of the rod crossed by the bar to become visible. Once the bar reaches the back (rightmost) tip of the rod, the entire rod would have been painted the color of the dot - signifying that the entire rod is now visible to us, all of its light having reached us. Having been informed as to the precise manner in which a rod's light reaches us, take note that the content of the material just presented applies equally to rods in motion as it does to stationary rods.

When we envisioned the 'growing bar' representing the sequential arrival of light from the rod, we imagined the bar to grow at a rate convenient for our visualization purposes. Because what we were dealing with was a 'mental model', there was in essence no 'right' or 'wrong' speed at which to visualize the passage of the bar: in the mental model, the growing bar representing the light from the rod that has become visible can assume any speed we desire. So that the material can be properly understood, however, we must address the process that the growing bar represents as it occurs in reality. To understand what is to be addressed, we must become familiar with a concept that is the topic of that discussion: the speed of light. The speed of light is a rate of activity far beyond our everyday experience. The speed of light is so fast that it can't be grasped based upon the restrictions set down by what we can and can't experience. Our best understanding of the speed of light, you see, exists confined to mathematical figures and limited mental concepts. Having been introduced to the speed of light, let us now become aware of how the speed of light relates to light arriving from a rod being perceived. When you first view a rod and see its front tip before seeing the rest of the rod, nature has the obligation of immediately "filling in" the parts of the rod that you don't see. How quickly does this occur? When nature reveals the light from the rod in the familiar sequential, piece by piece fashion described earlier, nature goes about performing the task as fast as nature can: at light-speed.

Light, you see, is nature's fastest medium for conveying information. When nature "fills in" the parts of the rod we haven't seen, nature does it in the form of a light-speed scan from the front tip to the back tip of the rod. Given the rate at which light travels, how would one perceive an occurrence presented at such a speed? Or how would we imagine the growing bar in the 'mental model' performed earlier to take place at the speed of light? In real life, the whole process of the rod's light reaching us would occur within a period of time no greater than the tiniest fraction of a second imaginable, seeming to us to perhaps take no time at all. Though the light from the rod would be reaching us in a sequential, tip to tip manner, our senses would be unable to detect this property of the arriving light - and would assume that the entire length of the signal had simply occurred simultaneously. As we are aware, in real life feats of nature such as the contraction of rods in motion occur at near-light speeds. To actually witness the details of such an occurrence, however, would appear to be an impossible task. Though we can't experience this light-speed activity at the speed at which it actually occurs, we are in response to this situation to rely upon models - whether mental or physical - as the means of "slowing down" these processes to a more suitable pace. When acting upon such models, we are to do so in awareness that the process we are experiencing in model form is simply a "slowed down" version of a far faster occurrence that exists in reality. Let this present to us a clear picture of the nature of the speed and behavior of light.

Now that we've been made thoroughly familiar with the sequential, piece by piece manner in which a rod's light reaches us, we will become familiar with the specific terms related to the process. What we know as a fact, first of all, is that when an observer first views the front tip of a rod (whether brought about by means of the first instant one views a stationary rod before him, or as the result of a rod in motion entering into one's field of vision), the front tip of the rod is the only part of the rod that the observer sees. The observer's act of viewing the front tip of the rod is what we will now refer to as the trigger point. The observer's act of viewing the front tip of the rod is a 'trigger' in the sense that it dictates the beginning of the rod being revealed to the observer: the light begins to leave the rod in the sequential, piece by piece manner that we have been made familiar with. This process is not new to us. For the sake of convenience, however, we will as of now refer to the process as the rod scan. The 'rod scan', you see, is the unavoidable outcome of the occurrence of the trigger point. As you may recall, we envisioned the rod scan in the form of a colored, growing "bar" that travelled from one tip of the rod to the other. This bar - the element that makes the rod scan possible - will as of now be referred to as the scan bar. We will now address the final term. The period of time in between the trigger point and the completion of the rod scan is called the contraction period. What the rod does during the 'contraction period' determines what contraction-related effects the observer will perceive the rod to undergo. We are now ready to take the next step in understanding the process of rod contraction.

As the means of moving on to the contraction-related concepts to come, we must address the mechanism by which rod contraction works. We will do this by approaching the material from as basic a level as possible: we will familiarize ourselves with the interface we will be working with - the interface that makes understanding the contraction process possible. We are to picture in our minds a rod - a horizontal pole - nothing more and nothing less. We will now perform an experiment upon what is given. Imagine a dot to lie in the very center of the rod. This dot represents a clock attached to the rod. The clock is set to tick once per second. This being our first experiment, we will imagine the bar to be stationary. Next, we allow the clock to tick 3 times (1 tick per second). When each tick occurs, imagine a short vertical line to be laid down on top of the clock so that the line is horizontally aligned with the clock. The result is 3 vertical lines - 'marks' - all laid down at the same spatial location. Because the rod was not moving, no influence existed that could alter the clock's location in space since the previous mark. For the next experiment, imagine the rod to engage in motion to the left for a duration of 3 clock ticks (3 seconds). As the clock in the center of the rod moves along with the rod, imagine, as before, a 'mark' to be laid down by the clock on its location at the moment each tick occurs. What happens now? The marks are observed to exist in spatially separate locations. It's not difficult to see why: because the rod was moving, the clock was carried to a spatial location separate from the previous mark during the delay in between ticks. As part of the next experiment, 'reset' the rod's position, and move the rod along to the left as before, placing marks where the ticks occur. This time, however, imagine the rod's rate of motion to the left to be twice as slow as in the original motion-related experiment. The result of the rod moving twice as slow: the marks, quite clearly, are twice as close. This occurs because less of a distance is travelled in between ticks. 'Reset' the rod's position, and this time imagine the rod's rate of motion to the left to be twice as fast as in the original motion-related experiment. After giving twice the speed to the rod, we find that twice the distance exists in between marks. This is the result of more distance being travelled in between ticks. Let the material we have just encountered dictate to us the nature of the interface we will be working with.

Our present goal is to combine the 'ticking clock' knowledge we just obtained, with all knowledge we have encountered on the topic of rod contraction up to that point. Upon reviewing the material, 2 concepts stand out above the rest. The first concept states that upon being viewed, a rod's light is not immediately visible: the rod's light reaches the observer in a sequential, piece by piece manner by means of a linear scan from the tip of the rod nearest to the observer to the tip of the rod farthest from the observer. The second concept, equally as vital, states that the linear scan just described occurs at the speed of light. Having emphasized this knowledge, how shall we apply it? We are once again to picture a stationary horizontal rod - nothing more and nothing less. Next imagine 3 dots to lie along the length of the rod: one on the rod's left tip, one in the center, and one on the rod's right tip. These dots represent clocks attached to the rod. These clocks are set to tick sequentially from left to right, with a one second delay in between ticks: the first second brings about the tick that the leftmost clock gives, the second second brings about the tick that the center clock gives, and the third second brings about the tick that the rightmost clock gives. The total process lasts a duration of 3 seconds. What, then, does this 3-clock device represent?

This 3-clock device is a condensed, automated portrayal of the process of rod contraction. The sequential ticking of the clocks from the leftmost to the rightmost clock is the means of simulating the sequential, piece by piece manner in which a rod's light reaches an observer. The linear progression in which the clock ticks advance across the rod, to further describe the process, is meant to represent an extending scan bar: each new tick the device performs, you see, is to be considered the equivalent of a scan bar moving forth into a new region of the rod. Though this device may in some ways seem to be a limited, lesser version of the process it portrays, it has yet, as you will see, to make known how effectively it can simulate the contraction process. Since the scan bar, in real life, does what it does at light-speed, we are to consider the sequential ticking occurring across the length of the rod to be what we understand to be light-speed. As the means of putting what we have been discussing into practice, we will now bring our understanding of the process of rod contraction up a notch as we are presented with models of 3 contraction-related situations: a stationary rod, a rod passing by at half the speed of light, and a rod passing by at light-speed. The speeds of these rods, as you can see, being near-light speeds, suit the nature of the process of rod contraction - a process that itself occurs at near-light speed.

How does a stationary rod relate to the contraction process? In order to be properly introduced to how our contraction-simulating 3-clock device operates, we must first make as simple a use of it as possible - we will bring into the situation a stationary rod. We are to picture in our minds our 3-clock device (a horizontal rod, as you may recall, with a clock attached to the rod's left tip, the rod's center, and the rod's right tip). As the next step in understanding our contraction device, we will demonstrate the basic concept behind how it works by performing a light-speed trip from the leftmost to the rightmost clock of the device, all performed within the mind. The light-speed trip being discussed, as you may recall, is the process that we have referred to as the rod scan. The act of the rod scan occurring, take note, is as described a sequential passage performed across the contraction device at a rate of one clock tick per second. One clock tick per second can also be considered what we understand the speed of light to be, because in reality a rod scan is a light-speed process. By thinking of the speed of light in the way just presented, we are thinking of the speed of light as being defined by events (clock ticks). Given that we can view the speed of light in this way, what if we had the intention of thinking of the speed of light not as being defined by events (clock ticks) but rather by means of spatial distance (the distance that light can travel within one clock tick)? We would bring into being a term created out of its own necessity. Clocks mark distance - but are not the distance itself. The distance that light travels in one clock tick will be referred to from now onward as a section. A section is a measurable, definable, documentable distance that we will relate to in material to come. On the topic of clocks ticking, it is vital that we are introduced to an aspect of using a contraction device without which the contraction device could not perform: points of light. When we perform our passage across the length of the contraction device we are working with, we are to imagine each clock to emit a point of light when it ticks - a point of light that comes into being at the location of the tick, and remains there lit up for the duration of the contraction-related process. Points of light, in being left behind, allow us to mark where certain parts of the contraction device were during specific instants in time.

Let us now approach the issue before us. The trigger point occurs when the leftmost clock ticks, emitting a point of light. After one second the clock in the center ticks, also emitting a point of light. One second later the rightmost clock ticks, leaving behind the final point of light. What can be concluded from the points of light left behind by the clocks? The locations of the points of light tell us where certain parts of the contraction device were when the light from that part of the contraction device left the contraction device. When we compare the distances between the points of light left behind by the clocks to the distances between the clocks on the actual physical contraction device, we find that the points of light are in perfect alignment with the clocks. It's not difficult to see why: the contraction device was not in motion during the period of time in which the points of light were emitted. As a result, no influence existed that could possibly carry a point of light away from its original position as designated by its position on the contraction device. The device, put simply, was stationary. The points of light brought into being, take note, represent our basic conception of how the light of the rod we've been studying has reached us. Studying the distances in between points of light, you see, is our means of understanding the contraction process. What the locations of the points of light just set down tell us, take note, is that the version of the rod that we experienced - our perception of the rod - was of a rod equal in length to the actual physical length of the rod being perceived.

We will now visualize a rod passing by at half the speed of light. Now that we have been given a proper introduction to the contraction-simulating device we are now familiar with, we can consider ourselves to have arrived at the very point at which we will learn how and why rods in motion contract in the direction of travel. Once again, we are to picture in our mind the familiar 3-clock contraction-simulating device. The experiment that lies before us is different from the previous experiment involving a stationary rod in the sense that in the current experiment, forward motion of the rod will occur. We are to picture the contraction device to lie on the right side of our mental field of vision, and to imagine the device to begin to engage in forward motion to the left, toward the central region of our mental field of vision - at a speed that we understand to be half the speed of light. This speed can be of as little or as much of a speed as visualization purposes require. During the device's engagement in motion to the left, the rod scan occurs: the clocks tick in sequence from left to right, leaving behind points of light, while at the same time the contraction device continues in the straight line that its direction of travel leads it. As before, there is a one second delay in between ticks. The result: a row of 3 evenly spaced points of light separated by distances half the length of the distances observed to occur in between clocks on the contraction device. That is, contraction has occurred - the perceived version of the rod (the points of light) is shorter than the length of the actual physical rod. To better understand how and why this happened, we will repeat the experiment just performed. This second time, however, we will describe the process in greater detail, addressing aspects of what took place that perhaps were overlooked.

We are once again to picture the contraction device to lie on the right side of our mental field of vision, and to picture the contraction device to engage in forward motion to the left at a speed that we understand to be half the speed of light. The trigger point occurs when the leftmost clock ticks, placing down a point of light at the leftmost clock's current location, and bringing about the sequential, clock to clock passage across the length of the contraction device. This point of light represents where the left end of the contraction device was when its light left the contraction device. We, being observers of the contraction that is occurring, are to document this placement of the point of light. Given that the leftmost clock has just ticked, we are to consider the contraction device to be one second away from its next tick. The point of light just described (that had previously been the leftmost clock) is now one section (the distance light travels in one clock tick) ahead of the central clock of the contraction device. It is during the present one second delay that the central clock is carried toward the point of light ahead of it. How close the central clock gets to the point of light is determined by how far the central clock travels during the one second delay given it. The faster the central clock's speed, you see, the closer the central clock will lie in comparison to the point of light ahead of it upon the arrival of the end of the one second delay. Based on the understanding that the contraction device is travelling at half the speed of light, the central clock would advance half a section toward the point of light ahead of it, given the reasoning that an entity's speed and how far it goes are directly related. After one second of time has passed since the last tick, the central clock itself ticks, placing down a point of light at the central clock's current location. This point of light represents where the central region of the contraction device was when its light left the contraction device.

Given that the central clock has just ticked, we are to consider the contraction device to be one second away from its next tick. The point of light just encountered (that had previously been the central clock) is now one section ahead of the rightmost clock of the contraction device. It is during the present one second delay that the rightmost clock is carried toward the point of light ahead of it. How close the rightmost clock gets to the point of light is determined by how far the rightmost clock travels during the one second delay given it. The faster the rightmost clock's speed, you see, the closer the rightmost clock will lie in comparison to the point of light ahead of it at the arrival of the end of the one second delay. Based on the understanding that the contraction device is travelling at half the speed of light, the rightmost clock would advance half a section toward the point of light ahead of it, given the reasoning that an entity's speed and how far it goes are directly related. After one second of time has passed since the last tick, the rightmost clock itself ticks, placing down a point of light at the rightmost clock's current location. This point of light represents where the right end of the contraction device was when its light left the contraction device. The point of light left by the rightmost clock, in further description, designates the back tip of the contraction device, completing all contraction-related activity. The locations of the points of light resulting from the procedure described above tell us that the version of the rod that we experienced - our perception of the rod - was of a rod equal to half the length of the actual physical length of the rod being perceived.

We will now visualize a rod passing by at light-speed. We are to picture in our mind the familiar 3-clock contraction-simulating device. We are once again to picture the contraction device to lie on the right side of our mental field of vision, and to imagine the device to begin to engage in forward motion to the left, toward the central region of our mental field of vision - at a speed that we understand to be light-speed. This speed can be of as little or of as much a speed as visualization purposes require. During the device's engagement in motion to the left, the rod scan occurs: the clocks tick in sequence from left to right, leaving behind points of light, while at the same time the contraction device continues in the straight line that its direction of travel leads it. As before, there is a one second delay in between ticks. As you may recall from earlier in the material, light-speed rods possess a property that sets them apart from rods travelling at lower speeds: rods travelling at the speed of light are perceived by observers to possess no length whatsoever! The result of the rod passing by at light-speed, then, is 3 points of light all occupying the same location. How can this be explained? The explanation as to why light-speed rods are perceived to possess no length does not require of us to go beyond anything we've already covered. To better understand the situation, we will repeat the above occurrence of a rod passing by at light-speed. The process will be described in greater detail, and aspects of what took place that were perhaps overlooked will be addressed.

We are once again to picture the contraction device to lie on the right side of our mental field of vision, and to picture the contraction device to engage in forward motion to the left at a speed that we understand to be light-speed. The trigger point occurs when the leftmost clock ticks, placing down a point of light at the leftmost clock's current location, and bringing about the sequential, clock to clock passage across the length of the contraction device. This point of light represents where the left end of the contraction device was when its light left the contraction device. We, being observers of the contraction that is occurring, are to document this placement of the point of light. Given that the leftmost clock has just ticked, we are to consider the contraction device to be one second away from its next tick. The point of light just described (that had previously been the leftmost clock) is now one section ahead of the central clock of the contraction device. It is during the present one second delay that the central clock is carried toward the point of light ahead of it. How close the central clock gets to this point of light is determined by how far the central clock travels during the one second delay given it. The faster the central clock's speed, you see, the closer the central clock will lie in comparison to the point of light ahead of it upon the arrival of the end of the one second delay. Based on the understanding that the contraction device is travelling at light-speed, the central clock would advance one full section toward the point of light ahead of it, given the reasoning that an entity's speed and how far it goes are directly related. After one second of time has passed since the last tick, the central clock itself ticks, placing down a point of light at the central clock's current location. This point of light represents where the central region of the contraction device was when its light left the contraction device. Take note that because the central clock advanced one full section forward during the one second delay, the point of light emitted by the central clock occupies the same location as where the point of light emitted by the left clock lies.

Given that the central clock has just ticked, we are to consider the contraction device to be one second away from its next tick. The point of light just described (that had previously been the central clock) is now one section ahead of the rightmost clock of the contraction device. It is during the present one second delay that the rightmost clock is carried toward the point of light ahead of it. How close the rightmost clock gets to this point of light is determined by how far the rightmost clock travels during the one second of delay given it. The faster the rightmost clock's speed, you see, the closer the rightmost clock will lie in comparison to the point of light ahead of it when the end of the one second delay occurs. Based on the understanding that the contraction device is travelling at light-speed, the rightmost clock would advance one full section toward the point of light ahead of it as a result of the rightmost clock's travel at light-speed. After one second of time has passed since the last tick, the rightmost clock itself ticks, placing down a point of light at the rightmost clock's current location. This point of light represents where the right end of the contraction device was when its light left the contraction device. Take note that because the rightmost clock advanced one full section forward during the one second delay, the point of light emitted by the rightmost clock occupies the same location as the points of light emitted by both the leftmost clock and the central clock! As before, the point of light left by the rightmost clock designates the back tip of the contraction device, completing all contraction-related activity. The locations of the points of light resulting from the procedure described above tell us that the version of the rod that we experienced - our perception of the rod - was of a rod possessing no length whatsoever.

We have just been informed as to the details of how and why a rod in motion is perceived to contract. Let us take this knowledge a step further. According to the theory of relativity, all of space contracts as measured by those travelling through space at near-light speeds. When we say that all of space 'contracts', we mean that all distances parallel to the observer's direction of travel are perceived by the observer to be shorter than they actually are, as a result of the observer's speed. The specific near-light speed at which the observer happens to be travelling, in turn, determines the degree to which all of space is observed to contract. The relationship between speed and degree of contraction, furthermore, can be successfully described by stating that the closer the observer's speed gets to the speed of light, the more contracted all of space will appear to be. In fact, if the observer were to reach light-speed, all of space would be perceived by the observer to possess no length whatsoever! This is the inevitable result of travel at the speed of light. So, then, you may wonder, the motion of some tiny spaceship on some distant edge of the cosmos is responsible for the entire universe contracting? How can that be? What is known for certain, firstly, is that the contraction of all of space observed to occur here is not a physical contraction. The occurrence of all of space contracting, you see, is an alteration of the observer's perception of his surroundings - and does not involve the surroundings themselves. How, then, does one visualize something as inconceivable as all of one's space contracting?

It so happens that such a mental feat is not actually necessary. There exists, you see, a useful 'shortcut' to visualizing 'all of space' that offers one a simplified alternative to the typical conception one would be expected to take on. This 'shortcut' will allow us to more effectively address key concepts relating to all of space contracting, through the construction of a model of all of space that removes all unnecessary complication. The material has made us familiar with the concept of contraction: the perceived shortening of distances extending parallel to an understood direction of travel (that occurs in the presence of speeds near the speed of light). We have been made familiar with 2 instances of contraction: rod contraction and all of space contracting. Both instances, take note, can be observed to be made up of 2 main components: observer, and contracted entity being observed. Each instance of contraction, as we will see, addresses each of these 2 components in its own particular fashion. In the rod contraction example, firstly, the observer (understood as our role) is stationary, and the contracted entity (the rod) is in motion. In the example of all of space contracting, on the other hand, what is stationary and what is moving has been switched: the contracted entity (all of space) is now stationary, and the observer (a ship travelling through space) is in motion. In each case, the need for the motion required for contraction to occur is met in its own way.

Having been made familiar with the effects motion plays in the contraction process, consider the following notion: if a stationary observer perceives a rod passing by at near-light speed to contract, how would an observer passing by a stationary rod at near-light speeds perceive that rod? We can conclude given our current knowledge that the stationary rod being passed by would be perceived by the observer to contract as a result of the observer's near-light speed. The observer's motion would be assuming the role of provider of the motion necessary for contraction to occur - a role that up until now was a job understood to belong to the rod. Of what importance, you may ask, is a stationary rod to us? A stationary rod being passed alongside by a moving observer is our working model of the 'shortcut' mentioned earlier - the shortcut allowing us to think of the concept of all of space with as little effort as possible. A stationary rod is an ideal choice for providing a simplified model of all of space, you see, because in reality, the reasons that a ship travelling through outer space at near-light speed perceives all of space to contract are the same reasons that a stationary observer perceives a rod passing by at near-light speed to contract. What, in further thought, makes a stationary rod a suitable alternative to the attempt to visualize 'all of space' directly? Both a stationary rod and all of space are stationary - they represent stationary distances being moved across. Both a stationary rod and all of space provide the traversable distance required for contraction to occur - the distance that is perceived to shorten when passed through at near-light speed. The 2 properties just described show us clearly that thinking in terms of a stationary rod is a valid option when faced with the challenge of envisioning the contraction of all of space. Exactly how, then, is such a visualization performed?

Visualizing a model portraying the perception of all of space contracting involves making use, once again, of our 3-clock contraction-simulating device. The device is not limited to rod contraction in terms of what it can accomplish, you see - it is equally able to simulate all of space contracting. Simulating all of space contracting, as stated, involves first being aware of the similarity that exists between a stationary rod and what we understand to be all of space. Once this has been done, we take the next step in visualizing all of space contracting and assume the stationary rod to be a contraction device. We do this, in review, by attaching a clock to the rod's left tip, the rod's center, and the rod's right tip. It's that simple. In doing so we make the stationary rod suitable for our visualization purposes. This stationary contraction device, then, represents a designated length of traversable space - a length that those passing by at near-light speeds will perceive to be shortened. By what rules, you may ask, does the contraction process now operate by? As before, the rod scan - the familiar clock to clock light-speed scan - is the factor dictating to us what can and can't happen. What is different is simply the way in which the rod scan does what it does. In order to better understand what we've been discussing, we will be presented with models of 3 contraction-related situations, each involving a contraction device and a flying space vehicle. In each situation, the ship's perception of the contraction device is determined by the speed at which the ship is passing by. The situations involve a stationary ship, a ship passing by at half the speed of light, and a ship passing by at light-speed.

How does a stationary observer perceive a stationary contraction device? We are to picture on the right side of our mental field of vision a stationary 3-clock contraction device. Below the contraction device, under the leftmost clock, and facing the contraction device, is a flying space vehicle hovering in place. The leftmost clock ticks, bringing about the trigger point, and a vertical bar appears directly under the leftmost clock. This vertical bar represents the first step in the formation of what we are referring to as the perceived distance record: a record of the ship's current understanding of how distance separates the clocks of the contraction device. The vertical bar, in turn, represents the ship's conception of where the leftmost clock of the contraction device is located. Given that the leftmost clock has just ticked, we are to consider the contraction device to be one second away from its next tick. One second of time passes and the central clock ticks. In response to the tick, a vertical bar identical to the vertical bar underneath the leftmost clock is placed directly below the central clock. This vertical bar becomes part of the perceived distance record and represents the ship's conception of where the central clock of the contraction device is located. The central clock having ticked, one second remains until the next tick. After one second of delay, the rightmost clock ticks. This brings about the third and final vertical bar: a vertical bar is placed directly below the rightmost clock. This vertical bar becomes part of the perceived distance record and represents the ship's conception of where the rightmost clock of the contraction device is located. What can be concluded from the placement of the vertical bar positioned under the clocks? The distances in between the vertical bars are no different that the distances in between the clocks of the actual contraction device. This is the case, quite simply, because the ship was not in motion relative to the contraction device it was perceiving. No influence existed that could alter the ship's perception of distances in between clocks. By examining the perceived distance record, we can come to the conclusion that distances perceived by the ship were no different than the actual distances in between clocks.

How would an observer passing by at half the speed of light perceive a stationary contraction device? We are to picture on the right side of our mental field of vision another stationary 3-clock contraction device. Entering into our mental field of vision from the left and approaching the contraction device is a flying space vehicle. It is travelling at what we understand to be half the speed of light. At the moment the ship reaches the area directly below the leftmost clock of the contraction device, the leftmost clock ticks, bringing about the trigger point as a result of the ship's arrival. In response to the tick, a vertical bar is placed directly under the leftmost clock and in being placed there attaches itself to the front tip of the ship. The vertical bar, in turn, represents the ship's conception of where the leftmost clock of the contraction device is located. This vertical bar, as before, represents the first step in the formation of the perceived distance record: the record, once again, of the ship's current understanding of how distance separates the clocks of the contraction device. The main influence capable of affecting the perceived distance record is, as we will see, motion relative to the contraction device being perceived. As the ship passes by the leftmost clock, the vertical bar, being part of the perceived distance record, is carried forward along with the ship. As the bar is carried along with the ship, we are to be aware that in the ship's mind, the perceived distance record is not in motion, but is rather an unmoving mental concept. Let this be made clear. Given that the leftmost clock has just ticked, we are to consider the contraction device to be one second away from its next tick. As time passes, the vertical bar, with the ship behind it, travels toward the central clock of the contraction device at half the speed of light. The central clock ticks. Given the vertical bar's speed, and given that the central clock just ticked, we can conclude that the vertical bar has advanced half a section beyond the leftmost clock - which it has.

In response to the tick that has just occurred, a vertical bar is placed directly under the central clock (half a section ahead of the vertical bar from the leftmost clock) and becomes part of the perceived distance record. This vertical bar represents the ship's conception of where the central clock of the contraction device is located. As the ship continues to engage in forward motion, both bars, being part of the perceived distance record, are carried forward together along with the ship. Given that the central clock has just ticked, we are to consider the contraction device to be one second away from its next tick. As time passes, the perceived distance record travels toward the rightmost clock of the contraction device at half the speed of light. The rightmost clock ticks. Given the perceived distance record's speed, and given that the rightmost clock has just ticked, we can conclude that the rightmost bar of the two bars making up the perceived distance record has advanced half a section beyond the central clock - which it has. In response to the tick that has occurred, a vertical bar is placed directly under the rightmost clock (half a section ahead of the vertical bar from the central clock) and becomes the final addition to the perceived distance record. This vertical bar represents the ship's conception of where the rightmost clock of the contraction device is located. By examining the perceived distance record as it exists in its current state, we can come to the conclusion that distances perceived by the ship passing by were half the length of the actual distances in between clocks.

How would an observer passing by at light-speed perceive a stationary contraction device? We are to picture once again on the right side of our mental field of vision a stationary 3-clock contraction device. Entering into our mental field of vision from the left and approaching the contraction device is a flying space vehicle. It is travelling at what we understand to be light-speed. At the moment the ship first reaches the area below the leftmost clock of the contraction device, the leftmost clock ticks, bringing about the trigger point as a result of the ship's arrival. In response to the tick, a vertical bar is placed directly under the leftmost clock and in being placed there attaches itself to the front tip of the ship. The vertical bar, in turn, in beginning the formation of what we understand to be the perceived distance record, represents the ship's conception of where the leftmost clock of the contraction device is located. As the ship passes by the leftmost clock, the vertical bar, being part of the perceived distance record, is carried forward along with the ship. Given that the leftmost clock has just ticked, we are to consider the contraction device to be one second away from its next tick. As time passes, the vertical bar, with the ship behind it, travels toward the central clock at light-speed. The central clock ticks. Given the vertical bar's speed, and given that the central clock has just ticked, we can conclude that the vertical bar has advanced one full section beyond the leftmost clock - which it has.

In response to the tick that has just occurred, a vertical bar is placed directly under the central clock (where the vertical bar from the leftmost clock is). This vertical bar represents the ship's conception of where the central clock of the contraction device is located. According to the perceived distance record, the leftmost and the central clock occupy the same location - no distance exists in between them. As the ship continues to engage in forward motion, both bars, as part of their being part of the perceived distance record, are carried forward together along with the ship. Given that the central clock has just ticked, we are to consider the contraction device to be one second away from its next tick. As time passes, the perceived distance record travels toward the rightmost clock at light-speed. The rightmost clock ticks. Given the perceived distance record's speed, and given that the rightmost clock has just ticked, we can conclude that the two bars of the perceived distance record that share the same location have both advanced one full section beyond the central clock - which they have. In response to the tick that has just occurred, a vertical bar is placed directly under the rightmost clock (where the bars sharing locations lie) and becomes the final addition to the perceived distance record. This vertical bar represents the ship's conception of where the rightmost clock of the contraction device is located. According to the perceived distance record, all three of the bars representing the locations of the clocks of the contraction device now share the same location! This is the inevitable result of travel at the speed of light: contraction of all of space to zero length.