What We’ll Find Inside The Atom

The telescope that Galileo built in the late 1500s had the magnifying power of a pair of inexpensive binoculars available in any Wal-Mart, but it was enough to open up a new world. With this simple instrument, Galileo could see that Jupiter has four moons and that the sun has spots, which led him to the conclusion that the sun was rotating. Most spectacular, he found that the planet Venus had phases—powerful evidence that the Copernican view of our solar system, in which the sun, rather than the earth, is at the center, was correct. As people built better telescopes, knowledge of this complex, beautiful new world of the cosmos evolved. We became aware of a vast universe filled with bizarre objects—pulsars, quasars, black holes—and that we were inhabitants of an insignificant dot, part of a galaxy of billions of stars carrying their own solar systems.

With a few minor technical changes, the telescope was turned inward at the world of the small. The microscope revealed a vast, complex world of microbes so tiny that a thousand could fit comfortably on the period at the end of this sentence. This world eventually came to include genetics, microbiology, viruses and bizarre new worlds many hundreds of times smaller than microbes: atoms! To explain the behavior of atoms, scientists had to invent quantum theory, which led to semiconductors and other technologies that account for a huge portion of the 20th century's economic output.

Such is the power of a good instrument. Since much of nature involves things too small or too distant or too subtle to see, scientific advancement has always required the invention of better tools. Today, the scientific world is witnessing the completion of a new tool, the Large Hadron Collider (LHC). This is no pair of cheap binoculars. It is expected to advance the magnification of the properties of objects by the largest factor in the history of particle physics—by some reckoning, 500-fold beyond what can be achieved today. The LHC is a particle accelerator—a monster-size circular underground tunnel, 4.3 kilometers in radius, located at CERN, the European Organization for Nuclear Research, on the Swiss-French border near Geneva. In the tunnel, powerful superconducting magnets steer protons around a ring where huge voltages accelerate them until they pick up an amazing amount of energy—7 trillion electron volts at their peak. Over the next few months, as technicians bring the vast machinery online, high-energy protons will be made to collide with one another, causing them to break up into thousands of smaller particles, whose short, violent lives will be recorded by nearby detectors. Although the LHC isn't the first collider ever to be built, it attains the highest energy. What this means is that the collisions that take place inside it will be more violent, and that it has the ability to produce 100 times the number of collisions per second of any other collider.

Like Galileo's telescope, the LHC will give scientists new insight into a new world of the very small and, indirectly, of the very large. What will scientists see with the LHC? The machine's reach and sensitivity may well reveal a new world, a gift to the 21st century. What kind of world? Five centuries of hindsight make it possible to enumerate the implications of Galileo's telescope, but we have no such luxury with the LHC. How would a contemporary of Galileo's have been able to extrapolate from the telescope to the iPhone? In view of the understanding humans now have and the blending of the many worlds revealed by the many tools and instruments built since Galileo, will the LHC deliver surprises?

It had better. In this age of tight budgets, the LHC, a worldwide collaboration of thousands of scientists, engineers, students, has cost $8 billion, including significant pieces of national budgets. To appreciate what impact the LHC is likely to have in the coming decades, it's necessary to take a look at the fundamental questions it was built to answer. Only by venturing a few steps into the labyrinth of particle physics can we get a sense of how deeply this tool will look into the nature of the physical world.

At present, complexity is the bane of physicists. The closer we look, the more complicated and unwieldy the physical world seems to become. For the better part of a century, physicists have aspired to some theory of the universe that is simple and beautiful, but what we've found instead is a proliferation of particles and a morass of forces that don't seem to fit together in a coherent way. It's like having a separate remote for the television and another for the DVD player, and along comes the DVR with yet another. What you want is one simple universal remote—in physics, a theory of everything. Nobody believes that the LHC will magically provide one, but we are hoping that it will at least help us tidy things up a bit.