Today, Einstein's goal of combining the physical laws of the universe in one theory that explains it all is the Holy Grail of modern physics.

In order to solve some of the deepest mysteries of the universe, the rules that govern large objects like galaxies must be combined with the rules that govern small objects like subatomic particles.

String theory is radically changing our ideas about the nature of space, opening up the possibility that extra dimensions, rips in the fabric of space, and parallel universes actually exist.