The distructive power of E=mc²

In the special theory of relativity, Einstein


stated that mass can be changed into energy, and energy to mass. Some people made use of this theory for distructive uses. Since the day when nuclear fission was discovered, people tried to create more powerful weapons using the mass-energy relation. For example, the atom bomb and hydrogen bomb. They uses the theory of nuclear fusion and fission to generate huge amount of energy.

So, does the E=mc² gives us only the power to destory?

That's a good question. The E=mc² gave us the power of distruction, but it also gave us the power to create. In nuclear power stations, nuclear fission is used. If einstein didn't gave us the mass-energy relation formula, nuclear power stations will not exist, and human will continue to depend on fossil fuel. Let's say that the mass-energy gives us both the power to destory and to build.

The mass-energy relation also helped explain the very begining of the universe. The first matter was created with energy. Everything in this world were once energy. Einstein learnt how god had created this world.

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The apple falls UP if the time is imaginary time

In the Newton laws, velocity is defined as (change in distance)/(change in time), and acceleration is defined as (change in velocity)/(change in time). Because velocity is a vector, it can change in two ways: a change in magnitude and/or a change in direction. According to Newton's Second law, 

where F is the resultant force acting on a body.


According to this definition, if we put (i)t into the formula, we get:

So, the force acted will be reversed. That means, in the world of imaginary time, an apple dropped will not fall DOWN, but UP.

Time Machines

In sci-fi movies or cartoons, the main characters can always travel back through time. We have discussed how time slows down before, however, we never know if time could be reversed. We can find the answer with the Time Dilation formula.

This time, instead of substituting v=c, we will substitute v=(√2)c. By doing that, we obtain:

Here iΔt is know as imaginary time. Imaginary time is different from regular time. If we imagine "regular time" as a horizontal line running between "past" in one direction and "future" in the other, then imaginary time would run perpendicular to this line as the imaginary numbers run perpendicular to the real numbers in the complex plane. However, imaginary time is not imaginary in the sense that it is unreal or made-up — it simply runs in a direction different from the type of time we experience. In essence, imaginary time is a way of looking at the time dimension as if it were a dimension of space: you can move forward and backward along imaginary time, just like you can move right and left in space.


To conclude, travelling back to past is not possible. There's no way something can travel faster than the speed of light. Even if a thing really did it, you still can't travel back to the past, as you will be travelling on a different "time line". So, we can just forget the dreams of reversing time.

Time Dilation

I discovered this clip in YouTube. The clip clearly explains how Time Dilation works. You should read my previous post again after watching this clip so as to understand the theory clearer.

E=mc²: Einstein explains his famous formula

This video should help you understand more easily about what the formula E=mc² predicts.

Why "c" is a Constant?

The special relativity stated that the speed of light will always be the same, no matter what. c=299792458 m/s when you are stationary, c=299792458 m/s when you are traveling at 99.5% the speed of light, c=299792458 m/s, no matter how fast you travel. But how did that happen?


It's the problem of velocity addition. For example, when you rune forward and throw a ball in the direction in which you are running, the ball moves faster than it would if you were standing still. If you can throw a ball 30 m/s when standing still, the same throw when you are running at 3 m/s gives the ball a speed of 33 m/s. You can summarize your ordinary experience in adding velocities as

where v is the velocity with respect to the ground, u' is the velocity of the ball with respect to you, and u is the velocity of the ball with respect to the ground. This is called the Galilean velocity addition formula. However, when it comes to Special Relativity, it doesn't work. The correct velocity addition formula, which was first given by Einstein, is

Now suppose one observer moves with velocity v relative to another observer. The first observer shines a light beam directly ahead of him at a velocity c measured in his frame. The speed of light as seen by the second observer can be found from the velocity addition formula given by Einstein.

That's why c is a constant.

Problem II

A free neutron is unstable and spontaneously decays into a proton and an electron. Th mass of the neutron is M_n=1.67495∙10^-27 kg, the mass of the proton is M_p=1.67265∙10^-27 kg, and the mass of the electron is M_e=9.1095∙10^-31 kg. How much energy is released when the neutron decays?


Click HERE for answer