Large Hadron Collider turned back on


Buttons glow in the control room of the Large Hadron Collider (LHC) at the European Organisation for Nuclear Research (CERN) near Geneva on April 5, 2012. At 0:38 CEST this morning, the LHC shift crew declared "stable beams" as two 4 TeV proton beams were brought into collision at the LHC's four interaction points. The collision energy of 8 TeV is a new world record, and increases the machine's potential to solve perplexing scientific questions. Top of the list: confirming the existence of the Higgs boson, a hypothetical particle posited to explain why matter has mass. Photo: REUTERS/Denis Balibouse