What is E=mc2

E=MC² is probably one of the best-known physics equations in the world, but few people really know what it means. The basic explanation of the equation is simple: E equals energy, M equals mass and C² is the speed of light in a vacuum [source:Stanford Encyclopedia of Philosophy]. The equation explains that energy and mass are intimately connected. In fact, they're so connected that mass can turn into energy given the right conditions. Even more surprising, though, is that the opposite also is true: If you compress energy enough, you can actually transform it into solid mass. For example, if you could shine two very strong sources of energy onto each other, the intense energy produced would actually cause small particles of matter to form.

The equation -- which Albert Einstein first demonstrated in 1905 -- might sound like it's straight out of a science fiction movie, but it has more practical applications than non-Einsteins might think. E=MC² is at the core of a number of scientific explanations. For example, the sun's existence can be explained using E=MC². Hydrogen and helium, the basic components of the sun, are elements of matter. As they fuse together, they cause a response similar to that of a fusion reactor that generates energy. A single kilogram of matter can produce 25 billion kilowatts of energy, which would explain why the sun is an intense ball of fire that keeps on burning [source: Science in Public].

E=MC² can't explain the big bang theory (the universe forming from nothing) completely, but it can explain how the universe expanded rapidly seconds after the initial explosion. At the time, mass and energy kept colliding and transforming back and forth, generating tremendous amounts of energy and creating more mass and expansion [source: PBS]. Breaking down Einstein's formula can help students trying to get through science, physics or astronomy classes see these concepts more clearly.

Many new technologies, such as carbon dating and positron emission tomography scans, make use of E=MC². And the formula explains how just a few ounces of uranium are enough to build a hydrogen bomb strong enough to destroy an entire city. Radium, another radioactive material, actually produces a luminous energy glow -- something that Marie Curie first realized at the end of the 19th century. The energy produced by radium is used today in radiology examinations as well as in everyday items such as luminous paints.