The Large Hadron Collider fired its first beam around the machine's full track at 10:28 AM local time (1:36 AM Pacific time).
No actual atoms were smashed today -- that won't start for weeks -- and no results are expected for months, at the earliest. Still, like first light in a telescope, the first beam in the particle accelerator is a landmark moment for a program that has spanned more than 20 years and involved tens of thousands of scientists.
"What has been shown today is that technically it all works," said Jos Engelen, chief science officer for CERN, the European scientific research agency directing the efforts, in a live webcast from Geneva.
The proton beams that raced around the 17-mile mile track begin a scientific relay that is likely to last for more than a decade. Scientists hope the discoveries made possible by the LHC will open new frontiers in physics and provide a new fundamental understanding of the universe.
Next up for the collider is cranking up the energy of the proton beams to about 10 trillion electron volts, more powerful than other particle accelerators like Fermilab's Tevatron but still short of the proposed maximum collision energy of 14 trillion electron volts that the researchers hope to reach.
The next big moment will come when the first particle collisions occur. That had been tentatively scheduled for the official LHC unveiling on October 21, but the first beam firings could lead to an acceleration of that schedule.
"Based on today's evidence, things are going to move faster," said Mike Lamont, a member of CERN's beam operations team in the CERN webcast. "There's a remarkable number of systems working remarkably well -- the instrumentation, the magnets. There's still some hurdles to cross there, but we can anticipate collisions sooner than we planned."