The Large Hadron Collider (LHC) reached a much-anticipated milestone today when it began smashing subatomic particles together at half its maximum power.
Earlier this month the "big bang machine" had broken its own energy record when it sent two 3.5-trillion-electron-volt (TeV) proton beams racing in opposite directions around the collider's 17-mile-long (27-kilometer-long) underground tunnel.
Today, at 1:06 p.m. local time in Geneva, Switzerland, LHC operators smashed those beams of protons together to create a record-shattering 7-TeV collision.
Reaching this point has been "marvelous," said David Evans, a physicist at the University of Birmingham in the U.K. and head of the LHC's ALICE detector project.
"I've been involved in [the LHC] personally for over ten years. ... It's like waiting ten years for Christmas to come," said Evans, who watched the collisions from the ALICE control center at the European Organization for Nuclear Research (CERN), which operates the atom smasher.
Large Hadron Collider "Like a Child"
As the first data from the impacts were announced, physicists who had gathered at CERN applauded, jumped up and down, and clutched laptops displaying images of the collisions to their chests as if the computers were newborn babes.
A large part of the excitement at CERN—and around the world—was relief that the Large Hadron Collider's previous electrical problems have had no lasting effect on the machine's ability to perform as expected, said Ian Shipsey, a co-coordinator of the LHC Physics Center at Fermilab in Illinois.
"When the machine started to do its early testing last fall, everyone was on a knife's edge. Every time the machine had a little problem, everyone imagined that it might have a disastrous meltdown," said Shipsey, who watched the show from half a world a way.
"Now there's a sense of relief mixed with joy, and everybody's pinching themselves to make sure that it's real."
Despite today's smashing success, it's anything but smooth sailing from this point on, said Richard Cavanaugh, also a co-coordinator at Fermilab's LHC Physics Center.
After all, there's still much to be done to ready the machine for the types of experiments scientists have in mind.
"This is a fantastic machine, but it's also very complex. It's very much like a small child," Cavanaugh said. "The child has just been born and we're learning how to raise it, and during the process the child is going to go through teething and adolescence before finally reaching maturity."
LHC Still Just Half Power
The current plan is to run the Large Hadron Collider at 7 TeV continuously for 18 to 24 months. Then the LHC will shut down for up to a year to prepare the machine for 14-TeV collisions—the atom smasher's maximum operating energy.
The LHC's record-breaking smashups could uncover evidence of dark matter, discover new forces in physics, unveil new dimensions, and even find the Higgs boson, aka the God particle, a theoretical particle that physicists think is responsible for mass in the universe.
"Two years of continuous running is a tall order both for the LHC operators and the experiments, but it will be well worth the effort," CERN Director General Rolf Heuer said in a statement.
"By starting with a long run and concentrating preparations for 14-TeV collisions into a single shutdown, we're increasing the overall running time over the next three years, making up for lost time, and giving the experiments the chance to make their mark."