The Large Hadron Collider, the world's new and largest particle collider, passed its first major tests by firing two beams of protons in opposite directions around a 17-mile underground ring Wednesday.
Scientists hope it's the next great step to understanding the makeup of the universe.
After a few trial runs, two white dots flashed on a computer screen near Geneva, Switzerland, at 10:26 a.m. (4:26 a.m. EDT) indicating that the protons had traveled clockwise along the full length of the $3.8 billion collider — described as the biggest physics experiment in history.
"There it is," project leader Lyn Evans said when the beam completed its lap.
Champagne corks popped in labs as far away as Fermilab in Chicago, where contributing and competing scientists watched the proceedings by satellite.
Five hours later, scientists successfully fired a beam counterclockwise.
Physicists around the world now have much greater power to smash the components of atoms together in attempts to learn about their structure.
"Well done, everybody," said Robert Aymar, director-general of the European Organization for Nuclear Research, to cheers from the assembled scientists in the collider's control room at the Swiss-French border.
The organization, informally known by its former French acronym CERN, began firing the protons — a type of subatomic particle — around the tunnel in stages less than an hour earlier, with the first beam injection at 9:35 a.m. (3:35 a.m. EDT).
"The beam is the size of a human hair," said CERN spokeswoman Paola Catapano.
Eventually two beams will be fired at the same time in opposite directions with the aim of recreating conditions a split second after the big bang, which scientists theorize was the massive explosion that created the universe.
"My first thought was relief," said Evans, a Welshman who has been working on the project since its inception in 1984. "This is a machine of enormous complexity. Things can go wrong at any time. But this morning has been a great start."
He didn't want to set a date, but said that he expected scientists would be able to conduct collisions for their experiments "within a few months."
The collider is designed to push the proton beam close to the speed of light, whizzing 11,000 times a second around the tunnel.
Scientists hope to eventually send two beams of protons through two tubes about the width of fire hoses, speeding through a vacuum that is colder and emptier than outer space.
The paths of these beams will cross, and a few protons will collide.
The supercooled magnets that guide the proton beam heated slightly in the morning's first test, leading to a pause to recool them before trying the opposite direction.
The collider's two largest detectors — essentially huge digital cameras weighing thousands of tons — are capable of taking millions of snapshots a second.
The CERN experiments could reveal more about "dark matter," antimatter and possibly hidden dimensions of space and time.
It could also find evidence of the hypothetical particle — the Higgs boson — which is sometimes called the "God particle" because it is believed to give mass to all other particles, and thus to matter that makes up the universe.
Previously unknown particles are also expected to pop up, if only for a millionth of a second, from the high-energy collisions of protons and antiprotons.
A pair of Russian scientists even think the LHC would be the world's first time machine, and that we should expect visitors from the future to arrive soon after it goes into operation.
The start of the collider came over the objections of some who feared the collision of protons could eventually imperil the Earth by creating micro-black holes, subatomic versions of collapsed stars whose gravity is so strong they can suck in planets and other stars.
"It's nonsense," said James Gillies, chief spokesman for CERN.
CERN was backed by leading scientists like Britain's Stephen Hawking , who declared the experiments to be absolutely safe.
Brian Cox, a glamorous particle physicist at the University of Manchester in England who literally was once a rock star, told London's Daily Telegraph that he and his colleagues had been receiving death threats.
He bluntly characterized anyone who feared the LHC would destroy the world with an unprintable term for a female body part.
That hasn't stopped several people, including a former nuclear engineer from Hawaii and a German biochemist, from speaking out against the project.
"Someone will spot a light ray coming out of the Indian Ocean during the night and no one will be able to explain it, retired Professor Otto Roessler told London's Mail on Sunday. "Very soon the whole planet will be eaten in a magnificent scenario — if you could watch it from the moon. A Biblical Armageddon. Even cloud and fire will form, as it says in the Bible."
"[T]he compression of the two atoms colliding together at nearly light speed will cause an irreversible implosion, forming a miniature version of a giant black hole," reads a lawsuit filed in March in U.S. District Court in Honolulu by Walter L. Wagner and a Spanish colleague, Luis Sancho.
The case, in which Wagner and Sancho demand that the LHC stop operations until an independent safety review is conducted, is still pending.
Gillies told the AP that the most dangerous thing that could happen would be if a beam at full power were to go out of control, and that would only damage the accelerator itself and burrow into the rock around the tunnel.
Nothing of the sort occurred Wednesday, though the accelerator is still probably a year away from full power.
The project organized by the 20 European member nations of CERN has attracted researchers from 80 nations. Some 1,200 are from the United States, an observer country that contributed $531 million. Japan, another observer, also is a major contributor.
Some scientists have been waiting for 20 years to use the LHC.
The complexity of manufacturing it required groundbreaking advances in the use of supercooled, superconducting equipment.
The 2001 start and 2005 completion dates were pushed back by two years each, and the cost of the construction was 25 percent higher than originally budgeted in 1996, Luciano Maiani, who was CERN director-general at the time, told The Associated Press.
Maiani and the other three living former directors-general attended the launch Wednesday.
Smaller colliders have been used for decades to study the makeup of the atom.
Less than 100 years ago scientists thought protons and neutrons were the smallest components of an atom's nucleus, but in stages since then experiments have shown they were made of still smaller quarks and gluons and that there were other forces and particles.
FOXNews' Paul Wagenseil and The Associated Press contributed to this report.