In the first stage in the life of the universe, in the first dimension of the universe, there is only time. The '1'st is '1', and '1' is Yang, and Yang is infinite. Time is infinite, and has no beginning or end. Space is finite, and has both a beginning and an end. The first dimension is before the beginning of space, and space does not exist in the first dimension.

In the second dimension of the universe, time gives rise to space. The '2'nd is '2', and '2' is Yin, and Yin is finite. Space is finite. Time gives rise to exactly as much space as can pass through this time. As space is finite, it will pass through a finite amount of time, and so time is also now finite.

Although both time and space exist in the second dimension, they cannot interact. Time is in motion, and time can only be in motion. Space is still, and space can only be still. All of space occupies a single point at the center of the universe.

In the third dimension, there exists light. The word 'light' is used herein to refer not only to visible light, but to all electro-magnetic radiation. Light enables time to interact with space, and light enables space to interact with time. The initial interaction of time with space due to light is known as the Big Bang, which began the third dimension of the universe, the universe in which mankind now lives. The Big Bang, the first light, perpetuated itself, causing all light. When light hits a unit of space-time, the light perpetuates itself, and that space-time reacts by emitting identical light. The first light wave continues to travel in its one direction, outward. Now, however, a 'child' wave is born. Each of these waves travels throughout the universe, perpetuating itself at each encounter with space-time, until the end of time and space. Once ignited, the cycle of absorbing and emitting light will never end until the end of the universe.

A fundamental difference between time and space is that time (Yang) flows in '1' (Yang) direction, whereas space (Yin) flows in '2' (Yin) directions. Therefore, whereas the Big Bang expands space outward (Yang) in all directions, away from the center of the universe, space will eventually flow in the opposite direction, inward (Yin), back to the center of the universe. Time, however, can only flow forward.

Light is the only force in the universe. Light is the only force that can enable time and space to interact with each other. The property of light that enables time and space to interact is known by a different name, 'gravity'. The gravity of light enables time (Yang), which is in motion (Yang), to be still (Yin), and enables space (Yin), which is still (Yin), to be in motion (Yang). Light enables motion in space, and light enables stillness in time. Light enables time to move through space, and enables space to move through time. The more time in space, the more space in time; the more motion in space, the more stillness in time. Light enables space-time.

What is space-time? Human beings and all other things in nature are, at and below the atomic level, composed of 'particles'. Each particle is a unit of space-time. These particles contain 'space', or mass, or matter. Space is that part of space-time that is still, and that has form.

And yet, such particles are always in motion. For example, electrons are in orbit around the nuclei of atoms, in the same pattern as the planets are in orbit around the sun. As well, electrons and nuclei are constantly in motion in the form of rotation, just as are the sun and all planets in the solar system. Particles of space-time therefore always contain time, or energy, or motion. Time is that part of space-time that is motion, and that is formless.

In the third and fourth dimensions of the universe, the dimensions in which light exists, there can exist no space without time, and there can exist no time without space. There can exist no energy that is entirely without mass, and there can exist no mass that is entirely without motion. The equation e = mc2 demonstrates that energy and mass are the Yang and Yin subdivisions of a single Yin existence, as each can evolve into the other.

Light is what enables space to interact with time. Light is what enables space to pass through time. As light cannot exist by itself, light is Yin. As with all subdivisions of Yin, light contain subdivisions that are both Yang and Yin. Light is Yang because it causes motion (in space in the third dimension and in time in the fourth dimension) and light is Yin because it causes stillness (in time in the third dimension and in space in the fourth dimension).

Light follows the same five stage cycle of evolution as mankind and the rest of the universe. Light is born, it increases, it decreases, it dies, and it perpetuates.

Each unit of space-time in the universe is constantly absorbing the continuous waves of light that are being emitted by all other space-time in the universe. In reaction to absorbing light, units of space-time emit light, and so light is emitted by a particle of space-time as a series of waves, each of which contains a finite amount of space-time.

At the moment of its birth, each wave of light is at the maximum rate of motion through space, and is at the minimum rate of motion through time. The speed of light, the rate of motion of light, is constant throughout space-time during the entire life of the light. However, the speed of light is not constant through either time or space.

A wave of light passes through zero time, and so does not age at all, until the wave expands outward and makes contact with the first unit of space-time. Only then can there be motion through time for the light that was only in motion through space, as the light interacts with the unit of space-time.

Light is born as motion in space, without motion in time. Each wave of light will travel throughout all of the remaining time in the universe, and will interact with all of the space in the universe. Once all light has traveled through all of space, and through all of time, light will die. As light encounters each unit of space-time, light ages, and moves forward through time, slowing by a corresponding amount its rate of motion through space. When light hits space-time, light decreases motion through space, by imparting a finite amount of motion through space to each unit of space-time that it encounters. Each unit of space-time that is hit by the light increases slightly in motion through space, and has a corresponding decrease in motion through time. This is transferred to the wave of light, causing a corresponding increase in the motion of the light through time. As light ages in time, it slows in space. As light ages, it imparts progressively less motion through space, and progressively more motion through time, to each unit of space-time that it encounters.

This cycle of emitting light and absorbing light symbolizes the Yang and Yin nature of light, as all aspects of light can be subdivided into Yang and Yin. Each new wave of light is '1'st (Yang) emitted, and is '2'nd (Yin) absorbed. Emission is Yang, and absorption is Yin. Light is emitted in the form of 'waves', and is absorbed in the form of 'particles'. Waves are Yang, and particles are Yin. Light that has been emitted by a particle of space-time travels in motion through space in one direction, 'away' or 'outward', and light that has been absorbed by a particle of space-time causes motion through space in the other direction, 'toward' or 'inward'. One direction is Yang (and 'away' and 'outward' are Yang), and the other direction is Yin (and 'toward' and 'inward' are Yin). Light is emitted as time (motion in time, stillness in space), but is absorbed as space (motion in space and stillness in time).

All space-time in the universe is constantly absorbing and emitting light. As a particle of space-time emits light, the light is in motion through space, and it is not in motion through time. As a particle of space-time absorbs light, it causes motion of the particle in space, and stillness of the particle in time. In other words, as light is in motion between two particles of space-time, it is only in motion in space. Time is still, and there is no motion in time. Only when the light is absorbed by another particle of space-time is the motion of the light through space stilled, and the stillness in space is accompanied by motion of the light through time; the light ages.

How does light travel through space-time? It is 'natural' to think of light as a particle (the word 'light' is a noun in English) that travels in a straight line (as a uni-directional ray) like a bullet, which hits or misses particles of space-time in its path. However, light does not travel through space-time in the form of particles, as particles are space, and space is Yin. Light travels in the form of waves, as waves are time, and time is Yang. The three dimensional line (or the two dimensional ray) is inadequate to symbolize the flow of waves of light.

What is the nature of light 'waves'? Imagine the surface of a pond as a finite four dimensional area of space-time. A rock that is dropped into the pond will radiate a wave of water over the surface that will eventually touch all points on the area. Light is emitted as a constant and continuous series of five dimensional waves in space-time. Light waves flow away from the source in one direction, outward, and will eventually make contact with all other space-time in the entire finite volume of the universe.

What is the nature of light 'particles'? All space-time in the universe is eventually 'hit' by all light. Therefore, the more space (mass) that a body of space-time contains, the more light that will be absorbed from each wave of light. All bodies of space-time, from atoms or smaller to solar systems or larger, absorb time (energy) in exact proportion to their space (mass). Each wave of light therefore affects each particle of space-time, regardless of its size, in exactly the same proportion, as though it had absorbed a 'particle' of light of constant mass and energy.

How do particles of space-time react when they absorb light? In the third dimension of the universe, light moves quickly (Yang) through space (Yin) and moves slowly (Yin) through time (Yang). When a unit of space-time absorbs light, there is an increase (Yang) in its rate of motion through space (Yin), and a decrease (Yin) in its rate of motion through time (Yang). In which direction does the motion in space flow? As light is in motion through space in one (Yang) direction, the light causes all space-time that it encounters to go in motion in the opposite (Yin) direction. The path through space of the light that hits a particle of space-time becomes a part of the particle's 'past'. Time flows in '1' (Yang) direction, forward (Yang), into the past (Yang). Forward in space is forward in time. Therefore, when a particle is hit by light, it moves toward the source of the light, just as animals move toward a source of light. The particle moves in the direction of the source of the light, as that is the direction from which the light came, that is the direction of the past, and time always moves forward, into the past. This is the source of 'gravity'. The more waves of light that hit a body from any one direction, the greater the 'pull' of gravity on the body to go in motion through space in that direction.

As each wave of light from a source travels outward, it continuously encounters space-time. Each unit of space-time that it encounters will convert more of its motion through space into motion through time. In other words, the light will age (greater motion) in time, and will slow down (lesser motion) in space. Light ages as it makes its way throughout the universe.

In the third dimension of the universe, space-time is expanding from the Big Bang. Light is in its growth stage. Light decreases in motion through space as it increases in motion through time. Therefore, while the speed of light is constant through space-time, the rate of motion through space slows as the light ages, as it moves farther from the source in space, and farther from the source in time. However, in the third dimension, light is still increasing the motion through space of the space-time that it encounters. Each wave of light that hits a unit of space-time will increase the motion of that space-time through space, and the universe will continue to expand.

In the fourth dimension of the universe, space-time ceases to expand from the Big Bang, and begins to contract. Light is in its declining stage. Light no longer increases the motion through space of the objects in space-time that it encounters. The rate of motion through time of light is now greater than the rate of motion through space, and so light now increases motion through time, and decreases motion through space, of the space-time that it encounters. When light reaches the end of the universe, and everything in the universe is at the same relative time, light will have used up all of its motion in space and will only be in motion through time. Light will die, space will die, and time will die.

The center of the universe has the greatest concentration of space-time, and so is the greatest source of light. Therefore, as all light in the universe ages, the momentum of the Big Bang will gradually slow, and the universe will gravitate back to the center.

As the third dimension is a Yang dimension, it begins (beginning is Yang) with a bang, with the maximum possible rate of motion through space, and the minimum possible rate of motion through time. As the fourth dimension is a Yin dimension, it ends (ending is Yin) at a crawl, with the minimum possible rate of motion through space, and the maximum possible rate of motion through time.

Waves of light can also be measured in terms of another subdivision into Yang and Yin, frequency and wavelength. The product of the frequency and the wavelength of the continuous waves of light that are emitted by a source is constant, and always equals the speed of light through space-time. Therefore, the greater the frequency of light, the shorter its wavelength, and vice versa. The frequency of light refers to the number of waves of light per unit time. The wavelength of light refers to the corresponding interval between successive waves of light.

The frequency of light is Yang, and the wavelength of light is Yin. Due to various factors, such as the size of a body in space-time, the amount of mass in its vicinity and the relative motion of this mass, etc., different units of space-time emit waves of light at various initial frequencies. As the waves of light from each source age, the light decreases its rate of motion in space and increases its rate of motion in time, and so the frequency of the light decreases and the wavelength increases. At the moment of the end of the universe, the frequency of that light will have decreased to close to zero, and the wavelength will have increased to close to infinity.

Therefore, the greater the distance in space between two objects in space-time, the greater the interval between successive waves of light from each that hits the other. The greater the interval between waves, the lower the frequency, and the longer the wavelength of the light from each source. Therefore, the greater the distance between two bodies in space-time, the less will be the attraction between them due to gravity.

The more distant in space-time a source of light, such as a distant galaxy, the more that the light that hits space-time on the earth has aged, and so the greater the increase in the wavelength of the light and the greater the decrease in the frequency of the light. This is known as 'red shift', as visible light shifts toward the longer wavelength 'red' light. The more distant a source of light in space, the more distant is the source of light in time, the more that its light will have aged, and the greater the red shift. Naturally, as the entire universe is still in a stage of expansion in the third dimension of the universe, the greater the distance between two points in space-time, the greater the cumulative expansion between them, and so the greater the relative motion, and the greater the rate at which each is receding from the other.

Light travels at one speed through space-time, the 'speed of light'. It is not possible to move faster or slower than the speed of light, as the speed of light is determined by the finite nature of the universe.

Why does an apple fall to the ground? Waves of light from the earth move outward in all directions, and eventually hit the apple in a tree. If the apple were freed from the tree, it would gravitate in the direction of the greatest light, which is toward the earth. As it approaches the earth, the frequency of the light that hits the apple increases. The closer to the source of light, the greater the frequency of light that hits the apple, the more that the motion of the apple through time is converted to motion through space, and so the rate of fall increases.

It has long been recognized that the rate of acceleration due to gravity is constant, and that the rate of increase in motion of objects through space does not depend on the mass of each object. The earth contains a large amount of space-time, and therefore emits a large amount of light. The earth is a large 'gravitational field'. Why do all objects accelerate equally due to gravity? The more space (mass) that an object contains, the more light that the object will absorb. The resulting change in motion through space is the same, and so gravity is the same for all objects.

Just as the speed of gravity is constant for all bodies in space-time, gravity is light, and so the speed of light is constant for all bodies in space-time. Thus, while subatomic particles vary greatly in size, each particle absorbs light in proportion to its mass, and so each particle accelerates at a constant speed, regardless of its mass. Each wave of light imparts to each of the particles of space-time in a body the same amount of change in motion through space-time. For example, whereas a proton is some 2,000 times as massive as an electron, it absorbs some 2,000 times as much light, which results in an identical change in motion through space-time, and so the speed of light, the speed of gravity, is constant, and both protons and electrons move at the speed of light.

Humans are aware of motion in time, humans are aware of time, by being aware of motion in space. The cycle of emission and absorption of light is the cycle of nature by which mankind is aware of and measures time. Between successive waves of light that a body absorbs, there is no change in motion through space of that body, there is no time, and so there is no stillness in time, and there is no awareness of time. It is the stillness of time, the motion in space, that enables mankind to be aware of time.

Humans are aware of motion in space, humans are aware of space, by being aware of motion in time. The cycle of emission and absorption of light is the cycle of nature by which mankind is aware of and measures space. Between successive waves of light that a body absorbs, there is no change in motion through time of that body, there is no motion in space, and there is no awareness of space.

Only as each body in the universe is hit by light can there be any motion through time or space, anywhere in the universe, and only in this way can there be awareness of motion through either time or space.

The fifth dimension symbolizes perpetuation, and light perpetuates itself each time that it hits a unit of space-time. The absorption and emission of light is how the space in each unit of space-time passes through time, how matter is converted to energy. When light is emitted, the remaining particle of space-time contains a little less energy (time), and a corresponding lesser amount of matter (space). Some space has passed through some time, and that time is now a part of that particle's past. The particle has aged, and the universe as a whole has aged.

All particles of space-time in the universe are constantly absorbing light from all other particles in the universe. Thus, the earth's gravity affects things on the earth. The moon's gravity affects the earth and all things on it. The sun's gravity affects all things in the solar system. The gravity from the center of the universe affects all things in the universe. All space-time affects all other space-time in the universe, and all of the time.

However, not all sources of gravity attract with the same strength. The more distant a source of light, the older the light, the more time through which it has passed, the lower its frequency, and the less the attraction of its gravity. All objects are constantly pulled in all directions, and the net effect of all gravity on an object is that the object is attracted toward the 'center' of gravity of all light that the object absorbs. The earth is locally the greatest source of light, and its proximity ensures the relatively extremely high frequency of its light, and so everything on earth is attracted toward the center of the earth, and all space-time on earth reacts in concert with the earth to more distant centers of gravity, such as the sun.

Each person, each thing in nature, is constantly bombarded by light from other people and from all other things in the universe. The more light that hits a person, the more he increases in motion through space and the more he decreases in motion through time. As a person moves through space-time, his relationship with light from the universe changes, and so his relationship with space and time changes relative to everyone and everything else. The body of each person interacts with all other space-time in the universe, but only from his unique personal position in the universe.

Although the speed of light is constant throughout space-time, the speed of time is not constant throughout space-time. In other words, people are not in motion through time, and so do not age, at a constant rate, and whatever a person's rate at any given moment, it is not identical with that of any other person or thing in the universe. The gravity in the universe is constantly evolving, the sources of gravity in each person's immediate environment are constantly changing, and so the rate of motion of each object through time is different from all other objects, and is constantly changing. Therefore, just as each person has a unique history and life experience, each person will have a unique and constantly changing 'body' time. The greater the mass and the motion through space of that mass in the vicinity of a person, the greater the gravity that affects the person, the greater the motion of the person in space, the less the motion through time, and the slower that the person ages. Thus, if one of twin brothers goes out for a jog, that brother will encounter a greater frequency of light during the jog than the brother at home, and the body of the brother in motion will age slightly less than the body of the still brother over the same period of 'society' time.

People sometimes feel that time seems to pass more slowly when they are relaxing than when they are busy and in a hurry. Time actually does pass at a different rate. More energy, more motion in space, means that less body time elapses relative to society time. It is important to understand that motion through space is not limited to motion 'from here to there'. The greater the consumption of energy, the more that the atoms in a body are in motion, although the body might not appear to be moving 'from here to there'. Breathing, digestion, stress, etc. are examples of energy consumption that is not accompanied by apparent motion through space.

People are not aware of increases or decreases in their own body time, but instead recognize differences as decreases or increases in society time. Body time passes more slowly when people are busy. This results in less body time per unit of society time, and it is society time that people learn to use to measure time. The slower the rate of a person's body time relative to society time, the more quickly society time will be perceived to pass. As well, people expend less energy at night than during the day, their bodies have less motion through space, and so people age more quickly at night.

When human eyes look upon any given object, a source of light, the closer the source is in space, the greater will be the frequency of light, the greater will be the gravity, from that object. Any increase in the motion of an object through space, relative to the motion through space of an observer, will be recognized by the observer as an increase in the space that the object contains, and so the larger the object will appear to the observer. As well, the more space-time that an object contains, the more light that will be emitted, the more that will be absorbed by particles in the eyes, and the larger that the source will appear to the observer.

If two objects on the earth are not in motion through space with respect to each other, they are in equilibrium, wherein each emits light in proportion to its mass. As the objects approach each other at an increasing rate of motion through space, the difference in relative motion of each object to the other object increases. The increase in relative motion is accompanied by an increase in the frequency at which light is absorbed. Therefore, the greater the relative speed of each object, the greater the gravity on the other object, the greater the other object will increase in motion through space, and the more slowly time will flow for the other object. As an object approaches another object at a speed close to the speed of light, time for each object decreases toward infinity, and the space (mass) of each object increases toward infinity. Naturally, infinity can never be reached in a finite universe. For example, the faster that Joe runs toward Bill, or that Bill runs toward Joe, or that Joe and Bill run toward each other, the more each will recognize time to slow for the other (the other will age more slowly) and the more each will recognize space (mass) to increase for the other. Neither will recognize that he is also slowing in time and increasing in space, as people are not aware of increases or decreases in their own body time.

If an object in space-time could be in motion through space at the speed of light, it would not age, as there would be no motion through time. All motion of the object would be motion in space, and all stillness of the object would be stillness in time. No motion in time means that there is no aging. However, as the object encounters light from all different directions, there is competing gravity that reduces its rate of motion through space in any one direction, making it impossible to move at the speed of light through space.

If there were twin brothers, and one went for a ride in a space ship that travels through space near the speed of light for awhile, he would return younger than the brother who stayed at home. That is because while in motion in space near the speed of light, his motion in time would be near zero. The brother back home had less motion through space, and therefore more motion through time.

As each group of mankind left Africa to go in motion through space across the earth, there was a corresponding stillness in motion through time. People in Africa have moved the least in space, and so are the oldest in time. People who migrated to Australia and to the Americas have traveled the farthest in space, and therefore will have the greatest corresponding decrease in motion through time.

Because time can only flow in one direction, forward, time travel into the past is not possible, although time travel into the future is possible. If one twin were to go out for a jog, he would move into the future more slowly than the other brother. He would move into his brother's future. If a space ship could move through space at the speed of light, it would be possible to take a controlled trip into a date in the future, although it would not be possible to return to the time of the society back home.

It is possible to look back in time, but it is not possible to travel there. For example, a person who looks at the sun is looking approximately eight minutes back in time, as that is when the light that is seen left the sun. In fact, no matter how close an object is, everything that the eyes see is in the past, as it took time for the light from the object to reach the eyes.