Discovery: Bigger and Better

The smaller the thing looked at, the bigger the microscope needed, which is why the circular Large Hadron Collider at CERN, where they discovered the Higgs boson is 27kms long, and its detectors tens of metres across. However, to dig deeper still into the secrets of the Universe, they are already talking about another machine four times bigger to be built by the middle of the century. Roland Pease asks if it's worth it