IN SEARCH OF THE 'GOD PARTICLE'

"LET THERE BE LIGHT" -- THEN WHAT? SCIENTISTS ARE ON THE VERGE OF UNLOCKING HOW THE UNIVERSE FORMED

If the hype is to be believed, scientists may be mere weeks away from answering one of the most mysterious questions of existence: Why is there anything at all?

The long search for the so-called "God particle" may soon be over. And if it is, there will be Nobel Prizes all round for everyone in on the discovery.

Until recently, it had been assumed that this elusive particle (assuming it exists at all) would be found by an international team of scientists working on the world's most expensive experiment, taking place in Europe at a huge complex built across the French and Swiss borders. But that experiment has run into problems, giving a much smaller American team based in Batavia, Ill., the chance to beat the Europeans to the punch.

But what is the God particle? And if we find it, will it have been worth the time and effort?


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We live - as Madonna reminds us - in a material world. What then, we might ask, is the material of the material world made out of?

As you no doubt learned in school, science has discovered that everything in the universe - whether a worm or a star - is made out of a modest number of different entities called elements. These 94 naturally occurring elements come in a smallest amount called an atom, which literally means something that cannot be divided. For a while, it seemed as if the atom were the smallest part of the fabric of the material world.

But further investigation of the world of small things revealed that atoms are not uncuttable after all, but made out of yet smaller particles. By 1932, it was known that all atoms are made up of three particles, the electron, proton and neutron. The material world was reduced from the 94 differences of the elements to just the three differences of these subatomic particles. To scientists, who are in search of the utter simplicity and symmetry of nature, this was a pleasing discovery.

It would, however, have been naive to suppose that the search would end here. Two-and-a-half millennia earlier, ancient thinkers had realized that there can be no end to the search for elementary particles. Even the smallest particles have to be made out of something else. If the search is to arrive at a destination, it is clear that there has to be something peculiar about the world of small things.

Indeed the world at these smallest sizes is so different from the world that we see around us that we need a different set of principles to describe it. This description is called quantum mechanics.

Quantum mechanics tells us that, rather than fade into nothingness, the world becomes more and more energetic as we look at ever-smaller parts of it. If we peer at a tiny region of space we see that it is not empty but boiling with particles that pop randomly into and out of existence for tiny parts of a second. This description of reality is certainly puzzling, but we can take comfort that even that great American physicist Richard Feynman, who said that no one really understands quantum physics.

By the 1950s, dozens of these "elementary" particles - those smaller than protons and electrons - had been discovered. The Italian physicist Enrico Fermi was heard to say to an inquisitive student: "Young man, if I could remember the names of these particles, I would have become a botanist." This was not a happy state of affairs, and yet still the particles proliferated. By the 1960s, it began to seem as if even the physicists themselves could not take them quite seriously. Feynman named one particle the parton, after Dolly Parton. American Nobel laureate Murray Gell-Mann named his discovery the quark, after the sound (according to the novelist James Joyce) that a seagull makes.

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Even the most powerful microscopes cannot see these elementary particles. Instead, we use devices called particle accelerators, machines that smash particles into each other. The idea is simple. Smash two particles of the same mass and energy together, and the resulting crash delivers twice as much energy at the point of impact; occasionally, another particle comes into brief existence from out of nothingness.

The story of the universe begins with a Big Bang - a very hot and dense spot of radiation of almost no size that expands rapidly. That patch of light has been expanding and evolving for about 14 billion years. It has evolved into all the structures of matter we find in the universe, including observers like ourselves who tell this story.

If our current scientific description of the universe is reduced to a single statement, it is that the universe is a patch of light that evolved.

Particle accelerators recreate the conditions of the universe as it was close to the Big Bang. But scientists are left with a mystery. How did the light at the beginning of the universe acquire mass and become things like quarks and then atoms and then gas and rocks and us? The God particle may hold the key to this mystery.

The God particle's real name is the Higgs boson, named for the English physicist Peter Higgs, who, in the 1960s, was one of the first to predict its existence. To date, scientists have not managed to bring this particle into the world of observable things. But it is thought that it first existed about a tenth of a billionth of a second after the Big Bang and created a field of energy. This field had the property of conferring mass onto some of the massless particles out of which the early universe was made. The Higgs boson changed a universe of radiation into a universe in which some particles have mass and some of them don't. The Higgs boson tells us how light became stuff.

It was a New Yorker and Nobel Prize winning physicist Leon M. Lederman who first called it the God particle. Later, given all the fuss about whether it exists or not, he said he wished he'd called it "the goddamn particle." Finding the God particle is in principle easy. Insert enough energy into a small enough region of space, and it should appear as a spike of energy in a suitable detector. The passing existence - it exists for about a trillionth of a second - of such a particle is a glimpse of the universe as it was almost at the moment of its origination. (I won't say creation, that would be teasing and suggestive.) Putting energy into space may be easy in principle, but in practice putting in enough energy to find a particle as evanescent as the Higgs boson is technically very challenging indeed. The difficulty is in getting particles to travel fast enough, and to hit each other head on. Here we reach the limits of our current technical abilities.

Not surprisingly, the search for the God particle has required the construction of the world's largest machines. Currently, the largest machine in the world is the Large Hadron Collider (LHC), located near Geneva on the border between France and Switzerland. It is in part a circular tunnel over 16 miles long and 30 yards underground encased by 9,300 magnets placed at intervals along its length. The magnets are cooled to minus 456.34 degrees Fahrenheit, within a few degrees of the coldest temperature possible in the universe.

The project - also the world's largest experiment - employs over 5,000 scientists, many of whom will attempt to interpret the data received at four detectors housed at opposite compass points around the tunnel. The LHC cost an estimated $10 billion to construct (in the days when $10 billion was a lot of money), paid for mostly by Europeans but with an American investment of more than half-a-billion dollars. An American plan to build what would have been the world's largest collider (the Superconducting Super Collider) in Texas, housed in a tunnel 54 miles long, was canceled by Congress in 1993 after the projected costs spiraled; $2 billion had already been spent and 14 miles of tunnel dug.

Like all particle accelerators, the function of the LHC is straightforward: to accelerate and smash protons into each other. Protons are whisked around the tunnel, making over 11,000 circuits a second, given little nudges by the magnets so that their speed gradually accelerates to within 99.99% of the speed of light. Two beams of protons circulate in opposite directions, eventually focused so that they collide with each other at the four detector points, which must then record the results of over 600 million collisions per second.

A billion people around the world watched on television on July 10, 2008, as the LHC was switched on for the first time. It was a surprisingly lighthearted affair given the daunting size of the venture, not to mention the rumors flying around the Internet that the machine was going to create a black hole that would annihilate the Earth. It's true that when the LHC is fully operational, it will create black holes, but no scientist is alarmed by this prospect. The blackholes will be minute - subatomic sized - and benign.

But only nine days after it launched, something went wrong. An electrical fault caused a rupture in one of the magnets, which led to an explosion. On Sept. 19, there was a mechanical failure, and the LHC had to be turned off again. The LHC is not expected to be switched on again until July at the earliest.

While the LHC is out of action, the world's largest operational collider is the Tevatron in Illinois. It was due to be put out of commission in 2010 because of the LHC's superior power. Ironically, it is currently running at the peak of its power and efficiency. The Tevatron team now believes it has a very good chance of detecting the Higgs boson within the next two years. In fact members say they may already be seeing evidence of it. Eight recent collisions could be evidence of the Higgs emerging from the void. But eight out of thousands of millions of collisions is not enough evidence to be conclusive.

If the Higgs does exist, it will take the stage slowly, and shyly. The Higgs will be a sensation, but hardly an overnight one.

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Will the search have been worth it? It's an appropriate question during a recession. It's true that we are unlikely to see any immediate and obvious technological benefits even if we discovered the Higgs boson tomorrow. But then what immediate technological benefits came out of the space race of the '60s and early '70s? Mankind didn't go to the moon for the incidental benefits of the non-stick frying pan and the invertible ballpoint pen. It went to expand humanity's potential.

Science insists on our commonality. DNA analysis shows us that everyone alive today shares a mother who lived in Africa some 150,000 years ago. Our DNA also shows us that we are descended not just from apes but from slime, a story that takes our descent back some 3 billion years. But the story does not stop there. We are, as poets often remind us, made of star dust. In turn, the stars themselves are clouds of hydrogen gas that condensed and ignited. And even further back in time, before there was any hydrogen gas, the universe was once - for the merest moment in time after the Big Bang - a curious landscape in which there was a field of energy made out of Higgs bosons.

The story of science as we understand it today can now trace our descent - and the descent of all things - back to the origins of the universe. Surely that makes science the greatest story ever told. In a world filled with divisiveness of all kinds, how wonderful to be reminded that we are all in this together.

Christopher Potter is the author of "You Are Here: A Portable History of the Universe" (Harper), out this week.



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