Einstein's Special Theory of Relativity

This entry will explain as best as possible Einstein's Special Theory of Relativity and how it came about, as told by Gary Zukav's "Wu Li Masters."

In the year 1905, the same year Albert Einstein had published his paper proving that light exhibits particle-like properties, he also presented a paper solving the problem of the constant speed of light. It was well-known at the time that light of any kind always travels at 186,000 miles per second. The Michelson-Morely experiment displayed a curious thing, though -- light was ALWAYS measured to be travelling at 186,000 miles per second, even when the observer was quickly moving towards or away from the light source. This was confusing because one expects the speed something appears to travel to take the motion of the observer into account. For instance, if you are driving in a car at 75 miles per hour and a car is coming towards you at 75 miles per hour, it would look like the car was approaching you at 150 miles per hour. So it was considered a great puzzle that light somehow appeared to move the same speed no matter what speed you were moving towards or away from it. Physicists were asking how it was that light could change its speed relative to each observer like that.

Einstein solved the problem by assuming what was being questioned: that light really did travel at 186,000 miles per second, and that it would always appear to travel at that speed regardless of the observer's motion. In this way, the puzzle of the constant speed of light became the Principle of the Constant Speed of Light. Those two things being assumed true, and assuming that observers were taking the measurements in the exact same way, there was nothing left that could vary but time itself. So Einstein decided that time, mass, and distance itself changes with velocity. This way, light would appear to be going the same speed as it always does regardless of the observer's motion, because the length of the ruler and the rate of time changes in proportion with the change in velocity. By assuming to be true what was being questioned, and completely throwing out what was assumed to be true, Einstein made his breakthrough. Light speed was made constant, and mass, length, and time were made relative to the motion of the observer. This assertion leads to fairly exotic results, like the fact that as an object approaches light speed its mass approaches infinity and time slows to a stop.

This however is impossible to do because as it nears the speed of light, and increasingly immense amount of energy is required to increase speed because it is also increasing mass, which requires more kinetic energy to move. The most popular equation related to this breakthrough is E=MC2. This relates to Einstein's assertion that mass and energy are not merely related, they are the same thing and can be converted back and forth. This is why mass increases as speed goes up: the kinetic energy of motion makes the moving material essentially gain mass because it is gaining energy, because mass and energy are one and the same. In this equation, E=energy, M=mass, and C2 is the speed of light squared, which is a very big number -- the point being that each bit of matter is composed of an enormous amount of energy. This discovery led scientists to figure out how to blow atoms up to convert mass into energy, hence leading to the invention of the fission and fusion atom bombs.