...and they did it without creating those much-feared Earth-gobbling black holes!
From the BBC:
Engineers operating the Large Hadron Collider (LHC) have smashed together proton beams in the machine for the very first time.
The step was described as a "great achievement" for those working on the huge physics experiment.
The low-energy collisions came after researchers circulated two beams simultaneously in the LHC's 27km-long tunnel earlier on Monday.
The LHC will smash together beams of protons to shed light on the cosmos.
It's been a long road since the meltdown in 2008 just a few days after the LHC's initial start-up. Repairs continued until a few days ago to the fried superconducting magnets that are designed to guide two beams of protons as they circulate at near-light speed in opposite directions and then smash headlong into one another. These collisions are expected to reveal secrets of the laws of physics by recreating conditions that have not appeared in nature since a few trillionths of a second after the Big Bang.
Scientists will search for signs of the Higgs boson, a sub-atomic particle that is crucial to our current understanding of physics.
Although it is predicted to exist, scientists have not yet detected it.
The Higgs Boson is theorized to be the utimate source of all mass in the Universe, but because of it's anticipated large size, it has yet to be created experimentally. The discovery of the Higgs would be a one of those major milestones in the entire history of Science!
Will the LHC succeed? We'll probably only know for sure in about a decade as experimental conditions ramp up to full power and it becomes clearer how results should be interpreted.
The four main detectors at the LHC are: Atlas, the Compact Muon Solenoid (CMS), Alice and LHCb. Atlas and CMS are so-called multi-purpose detectors, while Alice and LHCb are designed with more specific scientific investigations in mind.
Cern's director of communications, Dr James Gillies, said the first collisions had taken place just as a news conference was underway on Monday to discuss progress following the machine's restart at the weekend.
"We didn't have time to analyse them then. We waited until all four of the (detectors) had seen good candidates (for collisions)," he told BBC News.
It's only Day 1, but the switch has once again been thrown. We are living in the "Golden Age of Cosmology". Hang on! It's gonna be an exciting ride!