The most powerful atom-smasher ever built could make some bizarre discoveries, such as invisible matter or extra dimensions in space, after it is switched on in August.
But some critics fear the Large Hadron Collider could exceed physicists wildest conjectures. Will it spawn a black hole that could swallow Earth? Or spit out particles that could turn the planet into a hot dead clump? Ridiculous, say scientists at the European Organization for Nuclear Research, known by its French initials CERN, some of whom have been working for a generation on the $5.8 billion collider, or LHC. " Obviously, the world will not end when the LHC switches on." said project leader Lyn Evans.
David Francis, a physicist on the collider's huge ATLAS particle detector, smiled when asked whether he worried about black holes and hypothetical killer particles known as strangelets. " If I thought that this was going to happen, I would be well away from here."
The collider basically consists of a ring of supercooled magnets 17 miles in circumference attached to huge barrel-shaped detectors. The ring, which straddles the French and Swiss border, is buried 330 feet underground. The machine, which has been called the largest scientific experiment in history, isn't expected to begin test runs until August, and ramping up to full power could take months. But once it is working, it is expected to produce some startling findings.
Scientists plan to hunt for signs of the invisible " dark matter " and " dark energy " that make up more than 96 percent of the universe, and hope to glimpse the elusive Higgs boson, a so-far undiscovered particle thought to give matter its mass. The collider could find evidence of extra dimensions, a boon for superstring theory, which holds that quarks, the particles that make up atoms, are infinitesimal vibrating strings.
The theory could resolve many of physics unanswered questions, but requires about 10 dimensions, far more than the three spatial dimensions our senses experience.
Critics of the LHC filed a lawsuit in a Hawaiian court in March seeking to block its start-up, alleging that there was " a significant risk that operation of the Collider may have unintended consequences which could ultimately result in the destruction of our planet." One of the plaintiffs, Walter Wagner, a physicist and lawyer, said CERN's safety report " has several major flaws." U.S. Justice Dept. lawyers representing the Dept. of Energy and the National Science Foundation filed a motion to dismiss the case.
In rebutting doomsday scenarios, CERN scientists point out that cosmic rays have been bombarding the earth, and triggering collisions similar to those planned for the collider, since the solar system was formed 4.5 billion years ago. The LHC is only going to reproduce what nature does every second, what it has been doing for billions of years. Doomsayers assume that the collider will create micro black holes, even if they appeared they would instantly evaporate, as predicted by the British physicist Stephen hawking.
When the LHC is finally at full power, two beams of protons will race around the huge ring 11,000 times a second in opposite directions. They will travel in two tubes about the width of fire hoses, speeding through a vacuum that is colder and emptier than outer space. Their trajectory will be curved by supercooled magnets, to guide the beams around the rings and prevent the packets of protons from cutting through the surrounding masgnets like a blowtorch.
The paths of these beams will cross, and a few of the protons in them will collide, at a series of cylindrical detectors along the ring. The two largest detectors are essentially huge digital cameras, each weighing thousands of tons, capable of taking millions of snapshots a second.
Each year the detectors will generate 15 petabytes of data, the equivalent of a stack of CD's 12 miles tall. The data will require a high speed global network of computers for analysis.
