Commentary: In praise of the LHC

  • 10 September 2008
  • From New Scientist Print Edition. Subscribe and get 4 free issues.
  • Lawrence Krauss



AS THIS issue hits the news-stands, we will be opening a new window on the fundamental building blocks of matter. This is guaranteed to change our understanding of what makes the universe tick, and to shed real light on its origins.

It is the switching-on of the Large Hadron Collider at CERN near Geneva in Switzerland that is opening this window, and as spectacular as the LHC is to anyone who has seen it, you have to be a physicist working on elementary particles to really grasp what the excitement is about. For us, 20 years of anticipation will reach its climax when the LHC is switched on - at the time of writing scheduled for 10 September - and the first beams of protons collide into each other. This is truly a once-in-a-generation occasion.

During the late 1960s and early 1970s, theoretical physicists developed what we now call the standard model of elementary particle physics. We know of four forces in nature, but in 1965 we understood only one of them in terms of quantum theory. By 1975, following a frantic period of theorising, we had built a basic framework to help us understand three of the four forces.

These remarkable developments still left us without a central piece of the puzzle. We could produce predictions that turned out to accurately match every measurement made since the 1970s. But a key feature of understanding the weak force involves understanding why the quanta conveying this force are heavy, while the particles that convey the electromagnetic force are light. In other words, we needed to understand the mechanism behind the generation of mass.

What has been frustrating is that we have had every reason to believe this mechanism is close to the limits of where current and past generations of accelerators could probe. The disastrous decision by Congress in 1993 to cancel the Superconducting Super Collider meant that theorists and experimentalists have been left hanging for almost two decades. The Tevatron collider at Fermilab in Batavia, Illinois, might have got lucky, but it didn't.

What made this even more frustrating is that understanding mass fully could help us with big questions such as why gravity is so different from the other forces, why the universe is made of matter and not antimatter, whether our universe is unique, and if hidden dimensions exist. All this and more is on the line as the LHC powers up. Whether we see spectacular new matter or discover that our current ideas about what lurks beyond the limits of detection are wrong, physics will never be the same.

At this point, there are those who may counter: "Big deal. What does all this matter? We can function perfectly well, even in science, without addressing such esoteric and expensive questions."

To answer this, I continue to draw inspiration from a line from the late Austrian-American physicist Victor Weisskopf. Large accelerators, he said, are the Gothic cathedrals of the 20th and 21st centuries. He was right: they have pushed the limits of technology, embody the craftsmanship and skill of thousands of people, and have taken generations from conception to completion.

Cathedrals celebrate the glory of God: the LHC will celebrate the glory of the natural world, and our uncanny ability to uncover its hidden details. Moreover, as the largest, most complex machine ever built, created by thousands of scientists from scores of countries, speaking dozens of languages, it is testament to science and humanity at their best. The project shows not only that humans can work together, it reminds us that we share a fundamental humanity - in this case, the desire to understand our origins and our future.

Probing the deepest secrets of the natural world is a majestic undertaking. The LHC is the latest, boldest step in a noble tradition of asking why. The kind of science which will be done at the LHC can, like art, music and literature, compel us to reassess our place in the universe. Regardless of the outcome and independent of the grand technology it spawns, that is its ultimate justification.

The LHC is the latest, boldest step in a noble tradition of asking why

Read all of Lawrence Krauss's columns

The Large Hadron Collider - find out more about the world's biggest experiment in our cutting-edge special report.

From issue 2673 of New Scientist magazine, 10 September 2008, page 48