E = mc^2

E = mc^2

BY : Rhiannon Nevinczenko

We've all heard of Einstein's famous equation E = mc^2. But how many of us actually know what that means?
The equation stands for "energy equals mass times the speed of light squared." (E being energy, m being mass, c being the speed of light, also known as universal constant, ^2 being the squaring.) This means that all matter is energy. But if that's true, how come we don't see them being interchanged? Why can't we, for instance, use the principle to teleport people and objects? If we are all just energy, why can't we walk through walls and fly and have super powers?
Consider the equation, and the role of the speed of light. Light speed is 186,000 miles per second. The numbers at this scale are so large that we have a difficult time visualizing them. To get an idea of how fast this is, consider that Earth is 92.96 million miles away from the Sun, and it only takes sunlight 8 minutes and 20 seconds to get to us. If you wanted to go 93 million miles in a car at 60 mph, it would take you about 177 years to do so.
So, back to c - the universal constant, the speed of light. C^2 = 34,596,000,000 miles per second. Basically, a very tiny amount of mass would be converted into an extraordinarily great amount of energy (and vice versa). That is why nuclear reactors and atomic bombs work the way they do - matter is converted into energy. For instance, taking an atom of a specific isotope of uranium (which is the largest atom found in nature), and throwing a neutron at it results in it splitting into two, far more stable atoms, which themselves release a neutron each that then react with other uranium atoms. In one example from WWII, half a dime's worth of mass was converted into energy that produced the same explosive force as would 15 thousand tons of TNT.
In other words, we do use E = mc^2, but it is only applicable in certain situations because of how much energy is actually contained in matter. And that's without even considering the electromagnetic forces keeping you from falling through your chair!
Photo credit: Ferdinand Schmutzer via Wikimedia Commons, public domain.

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