There’s a time machine on the Stanford University campus, and it runs day and night. It won’t hurl anyone into the past or future, but it does something almost as audacious: It reenacts events that occurred just after the Big Bang, when some of the pure energy that filled the cosmos became all the matter that now exists. Inside an 18-foot-high, 1,200-ton particle detector, matter and antimatter moving at nearly the speed of light smash into each other billions of times a second, shattering into subatomic debris that hasn’t existed for about 14 billion years. “We have the gall to believe that we can prepare a situation that is very analogous to what you had at the beginning of time,” says physicist Jonathan Dorfan, director of the Stanford Linear Accelerator Center. “We’re trying to understand what happened during an extraordinarily energetic part of the birth of the universe—and we do a pretty good job.”
Courtesy of Lawrence Berkeley National Laboratory
The BaBar particle detector at the Stanford Linear Accelerator Center is a marvel of electrical engineering. Beneath a massive iron door, opened for maintenance, lies a superconducting magnet and an elaborate array of electronic sensors that track billions of explosive collisions between matter and antimatter particles every second.
For four years, Dorfan and a small army of 600 physicists from three continents have been using two of the world’s biggest and most complex machines—the two-mile-long Stanford Linear Accelerator and the BaBar particle detector—to solve one of the ultimate cosmic mysteries: Why is there any matter in the universe at all?
