the world 's biggest and most powerful physics experiment is taking place as you read this year .
after problems that delayed the restart in march , scientists at the european organization for nuclear research -lrb- cern -rrb- completed final tests , enabling the first beams to start circulating sunday inside the lhc 's 17 mile .
operating accelerators for the benefit of the physics community is what cern 's here for , `` cern 's heart beats once more to the rhythm of the lhc .