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Journalism of Courage
A 27-km underground loop of magnets beneath a tranquil patch of farmland in Europe will soon go to work on the universe8217;s deepest mysteries.
For a research physicist, Sandra Ciocio knows all about the trials of the construction site. In recent years she8217;s seen 7,000 tons of sensitive equipment lowered down a 100-m shaft to prepare for a single grand experiment. The technology was groundbreaking and the schedule punishing. 8220;It8217;s been deadline, deadline, deadline,8221; she says. 8220;I haven8217;t had a holiday in five years.8221; But when the first real data begin to emerge this summer, the possible rewards should be worth the effort: a final explanation of one of the last puzzles of physics. 8220;I feel like crying,8221; says Ciocio. 8220;It8217;s like a dream come true.8221;
This particular mystery has a daunting history. More than 30 years ago scientists developed an elegant series of equations, called the Standard Model, that describes the make-up of the universe in terms of the relationship between a few fundamental particles and forces. But the model has gaps. One gap is the baffling issue of mass. Why are some particles heavy while others have no mass at all? According to the leading theory, the weight of a particle depends on how it interacts with a mysterious 8220;Higgs field8221; that permeates all space. So far scientists haven8217;t found any evidence that this field 8212; and its associated particle, the Higgs boson 8212; exists. They8217;ve been waiting for a particle collider big enough to perform the necessary experiments. The Large Hadron Collider was built to fit this bill.
The idea behind the collider is simple: get protons 8212; positively charged particles present in every atom 8212; going fast, crash them into each other and observe the fragments. The LHC will use superconducting magnets to guide the protons round and round the subterranean ring until they8217;re going almost as fast as light. The resulting collisions will release unprecedented amounts of energy equivalent to 100,000 times the temperature at the center of the sun. With luck, they8217;ll also produce, among a shower of lesser particles, the long-sought Higgs boson.
The collider may also throw up clues to puzzles that arise at the strange intersection of particle physics and astronomy. To understand the cosmos, scientists must understand how it developed from those first primordial particles. 8220;In effect, what we have is far and away the most capable microscope ever built, and the most powerful telescope ever built,8221; says theoretical physicist John Ellis. A central mystery is the supposed existence of invisible 8220;dark matter,8221; and its counterpart 8220;dark energy,8221; a strange force that seems to accelerate the expansion of the universe. Although together the dark pair make up for 96 percent of the universe, scientists know next to nothing about them 8212; only their gravitational effects. Those grand collisions may produce undiscovered particles that account for both. The collider might also reveal yet another set of particles, the 8220;superpartners,8221; needed to bolster the case for String Theory, a 8220;theory of everything8221; that proposes the existence of six extra dimensions and a universe constructed of tiny vibrating strings.
All this knowledge comes with a whopping price tag: the collider will cost about euro 3 billion. Its annual energy consumption will match the entire city of Geneva8217;s. The 1 billion collisions taking place every second, captured and filtered by underground detectors, will generate enough data to fill 100,000 CDs a year. But ultimate knowledge is worth it, says CERN boss Robert Aymar.
It8217;s entirely possible that after all this money and effort the collider8217;s detectors will find no trace of the Higgs boson. That would still make the project worthwhile, researchers say. It would indicate beyond doubt that the Standard Model, the basis of modern physics, requires a radical rethinking. 8220;Our theorist friends tell us to look this way or the other, but maybe Nature is telling us to look behind us,8221; says Tejinder Virdee, a physicist from Imperial College in London.
The Geneva experiments will keep scientists occupied for 20 years or more. 8220;This is truly a once-in-a-generation experiment,8221; says Virdee, 8220;but it will take a generation to do.8221; Setting up the world8217;s greatest experiment took more than a decade: fixing the nature of the cosmos will take a little longer.
-WILLIAM UNDERHILL Newsweek
