After some time from Big Bang our early universe is flooded with building block of matter. But how did pure energy turned into matter. It was a mystery until 1905 Einstein came with a famous equation E=MC2. This equation shows that energy and matter are different form of same thing. In nuclear explosion matter is converted into enormous energy. During the Big Bang the opposite event happens. Energy is converted into matter. As our universe expands and cools the pure energy is turned into matter that make our current universe.