AP Photo

The Higgs Boson: you know the deal. It's the last undiscovered particle in our current picture of all the fundamental particles in the Universe.

If we can find it, we'll either have a big clue as to what the next step to take in physics will be, or we'll be forced to admit that physics works too well, and many of the great hypotheses (supersymmetry, large extra dimensions, etc.) are highly unlikely to be within our reach. It all depends -- if we find it -- on what its properties are.