The amount of energy given out when matter is destroyed is equal to the mass of material destroyed multiplied by the speed of light squared. As light travels at nearly 300,000 kilometers per second you don’t need to destroy much matter to get a lot of energy. Destroying a single gram of plutonium gives out as much energy as burning 2 tonnes of oil.
What this equation says is that mass is just an incredibly compact form of energy. The mad thing is that Einstein came up with the idea just from thinking and doing maths before we had any real evidence for it. But now we know it’s true because we have nuclear power stations that work! We also know that the sun shines by converting mass into energy. It’s a useful little formula 🙂
Einstein discovered that matter and energy are really different forms of the same thing. The formula tells us how much energy a certain amount of matter is equivalent to.
Uranium is a radioactive element. Every second, many of the atoms in a chunk of uranium are falling apart because it is unstable. The pieces, which are now new elements with fewer protons, have a lower mass than the original uranium atoms. This mass disappears as energy according to E=mc^2. This is known as nuclear fission.
I am not going to add anything further to the great answers below but simply I can say … Once Einstein discovered the equation and its consequences the world we know has changed and now not only scientifically that we have great source of energy and powerful mechanism but politically and socially we have to watch out of the both sides to this equation and the ugly and the good one 🙂 However, it is an amazing discovery and one that I believe has a huge impact on our daily life from energy prospective.