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Special Theory of Relativity
by : Lim Weng Khong

Special Relativity. What kind of theory is that? Guess it's just another of those theories that came from the genius Albert Einstein. So what is it anyway and why is it important? Well, for one thing, it's prediction of time dilation (that time slows down when the relative speed of the observer is increased) has resulted in GPS satelites compesating for time dilation to prevent huge errors in their positional calculations due to the fact that the satelites are travelling at enormous speeds relative to the Earth. Anyway, to illustrate things in a more simpler manner, let's say you have been put into a space ship travelling at speeds close to the speed of light. You would not realize that time has slowed down, but to an observer on Earth (let's say he's looking at the space ship with a powerful telescope), you would appear to be moving very slowly! Why is this so? One of the postulates of General Relativity is that time is relative. Now what's that? To simply put it, the measurement of time depends on where you are. So to say, there is no single reference of time, which is there is no single clock that can give out the accurate time of everywhere in the universe. This theory has been extensively tested. Two extremely accurate atomic clocks with the same initial time have been placed in a satelite and on the ground respectively. It has been repeatedly found that after a certain amount of time, the clock on the satelite would've been slower than the clock on the ground (even though by only small amounts of time, ie. in the order of microseconds).

Another thing that this theory determined was that matter and energy are equivalent. This relation is described by the all-famous equation (now popular in baby milk advertisements for some weird reason) : e=mc^2 or Energy is equal to Mass times the Speed of Light squared. This equation had a profound impact on civilization due to the fact that it is this discovery that led to the invention of the atomic bomb. Because the value of c^2 is extremely high (9*10^16m/s), it follows that even a tiny amount of matter (uranium in the case of the A-bomb) could unleash an unbelievably immense amount of energy.

Furthermore, another impact of Special Relativity is that NOTHING can travel faster than the speed of light. This is indicated by the relativistic equation for mass :

              Rest Mass  
         mass = -------------------------
                      ( 1 - ( V/c)^2 )^1/2
What this equation shows is the faster an object moves, the larger its mass becomes. It also follows that a larger amount of energy will be needed to propel the object. Now notice that if the velocity (denoted as V) were to be equal to c, the denominator will become 0. Thus the Rest Mass will become infinately large. When used together with the e=mc^2 equation, this means that if the mass becomes infinately large, it can be followed than an infinitesmal amount of energy will be required! This makes the prospect of attaining light speed impossible (at least within the context of relativity).

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