Now imagine that you were going up in a rocket ship to begin flying out in space. First you would need to add rocket fuel to your tank so you have some energy to burn. Let’s suppose that you added rocket fuel and then you weighed your space ship on a big scale and found out that space ship and rocket fuel weighed together 10 tons, because your rocket was 5 tons and then you added 5 tons of rocket fuel..
You went up into space and flew around. You were burning rocket fuel and so as the fire came out of the back of your rocket, following Newton’s law, that states for every action there is an equal and exactly opposite reaction, the energy pushing out the back of your rocket was causing an equally opposite reaction in your rocket by pushing you ahead in space. You checked your fuel gauge and saw to your horror that you were getting near Empty, and so you rushed back to land on earth before your rocket fuel tank ran dry. You then weighed your rocket ship and found out that, yes, it was once again a rocket ship that was 5 tons, since you already burned up five tons of rocket fuel out in space, and it was turned into energy and gone, thus subtracting off that extra five tons in weight you had before you left space with a combined weight of ten tons.
Now according to Einstein, Energy, E, is equal to a mass of what we call ‘matter’ of some type multiplied by the speed of light squared. What this means is that there really isn’t a hard line separating matter from energy. You proved the general concept when you took what you would call ‘matter’, weighing 5 tons, and then by burning that mass to release the energy you needed, you flew around in space.
A table seems like ‘matter’ to you, quite solid, and not like energy at all, until someone lights a match and then suddenly your matter table turns into fire and its energy is released back into the EM energy field of the universe.
This was one of the revolutionary ideas of the early twentieth century, the revelation that the whole universe is made out of energy.
Now think about one of those greenish colored glow in the dark toys. You hold it in the sunlight, so it can soak up EM waves like a sponge and then you go into a dark closet and watch as it glows in the dark until every last EM wave breaks free and returns to the Universal Energy Field of the cosmos. One of the reasons why the energy busts out when that toy glows in the dark is that the glow in the dark toy, down at the atomic level, has an instability, such that when the atoms in that toy trap some EM energy, it cannot hold onto the energy and the energy winds up breaking free which is why you see light coming out of that toy when you take it into a dark closet. It is a random process which is why the toy glows for about five minutes and then fades away to a dim glow towards the end, as those last few trapped EM waves randomly find a way to break free and escape from atomic traps.
Let’s suppose that you were Einstein, and so being a real perfectionist, you wanted to know just how much ‘mass weight’ that glow in the dark toy had when it was full of extra EM wave energy. You also want to know just exactly precisely how much ‘mass weight’ it must have lost when, like the rocket ship that lost ‘mass weight’ when its energy escaped, the glow in the dark toy lost ‘mass weight’ when all those trapped EM waves got away from those atomic traps.
Well something as small as an EM wave, when it gets trapped in some atom, does not add much ‘mass weight’, so if Einstein tried weighing the glow in the dark toy, the scale was not sensitive enough to tell the difference, but where there is a will there is a way, and so he would have to go through all the measurements of everything under the sun made by scientists back in those days, especially those measurements no one understood at the time, and then like a jig saw puzzle, he would finally find out a way to get that done, for you see, Einstein was a perfectionist and a crude guess he did not want. He wanted the exact answer.
It is not my intention here to go into great detail about that famous equation, for all that is required is that people grasp certain basic concepts.
Let’s suppose that you invented a special rocket ship that burned fuel equally out of both ends.
A normal rocket fires fuel out the back and goes forward (an equal and opposite reaction). Below this a rocket fires fuel out both ends and because the force is equal in both directions, it goes nowhere, because it gains zero momentum.
Next consider the Doppler Effect by thinking about the sound a train makes when it goes by (a sound wave is a wave with a frequency, just like an EM wave).
The Doppler Effect. When a train is coming towards you the sound seems high pitched (weeeeeeeee) because the train is releasing sound waves while at the same time the train is moving towards you and therefore the waves are packed together (a higher frequency of sound waves reach your ears). When the train passes you suddenly the sound drops from a treble to a bass (wooooooooo) because you hear a lower frequency because the sound waves are spaced slight apart due to being released by a train moving away from you.
Now imagine that you are Albert Einstein, and you have been working on that problem of figuring out just how much energy is in a mass, right down to the last drop, and you have made progress, and you have all the latest data and observations, but you are stumped and seem to have hit a brick wall in those math calculations. You just cannot seem to come up with an equation that works, because something is missing.
Now imagine that you are Albert Einstein riding on a train, and you a pass a train station, and the train station is like that glow in the dark toy, because it is releasing light through its spot lights on the platform, and it is also like the rocket ship that has fire coming out of both ends, because the station has two lights, one on each side pointing in opposite directions. Well being Einstein, when you saw that it would start you thinking about that nagging problem and that really bad math equation that resisted all solutions, because you could not help wondering just how much ‘mass’ that train station would be losing by running those lights all night long. Then suddenly, you would find yourself wondering just how much would be lost on both sides of the building, and then you would start wondering how much momentum that station might have not gotten, because you see, there is some tiny momentum coming out of those two lights, that could push the station, just like when fire energy comes out of the back of the rocket and pushes the rocket. It wouldn’t be much, but it would be something.
Well one thing led to another, and it suddenly occurred to Einstein that the problem was that he was forgetting that when a ‘mass’ sends out energy in some form you have to consider that whole business about momentum. It just makes sense. Rocket sends energy out the back and goes forward. Train station sends energy out of two lights on both sides and goes nowhere, just like a rocket with two tail pipes on opposite sides. Now it is obvious that a train station is not getting some momentum, and so therefore it is equally obvious that it must be losing ‘mass’ through those two lights, because you don’t get something from nothing. That was the turning point for Einstein, as he began to work momentum into those equations, and then, to make a long story short, out came the right answer, E equals M C squared.