Thought Experiments


The Particle at the End of the Universe: Why We Care

I was once interviewed by a local radio station about particle physics, gravitation, cosmology, things like that. It was 2005, the centenary of Albert Einstein’s “miraculous year” of 1905, in which he published a handful of papers that turned the world of physics on its head. I did my best to explain some of these abstract concepts, waving my hands up and down, which I can’t help but do even when I know I’m on the radio.

The interviewer seemed happy, but after we finished and he was packing up his recording gear, a lightbulb went off in his head. He asked if I would answer one more question. I said sure, and he once again deployed his microphone and headphones. The question was simple: “Why should anybody care?” None of this research is going to lead to a cure for cancer or a cheaper smartphone, after all.

The answer I came up with still makes sense to me: “When you’re six years old, everyone asks these questions. Why is the sky blue? Why do things fall down? Why are some things hot and others cold? How does it all work?” We don’t have to learn how to become interested in science—children are natural scientists. That innate curiosity is beaten out of us by years of schooling and the pressures of real life. We start caring about how to get a job, meet someone special, raise our own kids. We stop asking how the world works, and start asking how we can make it work for us. Later I found actual studies showing that kids love science up until the ages of ten to fourteen years old.

These days, after pursuing science seriously for more than four hundred years, we actually have quite a few answers to offer the six-year-old inside each of us. We know so much about the physical world that the unanswered questions are to be found in remote places and extreme environments. That’s physics, anyway; in fields like biology or neuroscience, we have no difficulty at all asking questions to which the answers are still elusive. But physics—at least the subfield of “elementary” physics, which looks for the basic building blocks of reality—has pushed the boundaries of understanding so far that we need to build giant accelerators and telescopes just to gather new data that won’t fit into our current theories.

Over and over again in the history of science, basic research—pursued just for the sake of curiosity, not for any immediate tangible benefit—has proven, almost despite itself, to lead to enormous tangible benefits. Way back in 1831, Michael Faraday, one of the founders of our modern understanding of electromagnetism, was asked by an inquiring politician about the usefulness of this newfangled “electricity” stuff. His apocryphal reply: “I know not, but I wager that one day your government will tax it.” (Evidence for this exchange is sketchy, but it’s a sufficiently good story that people keep repeating it.) A century later, some of the greatest minds in science were struggling with the new field of quantum mechanics, driven by a few puzzling experimental results that ended up overthrowing the basic foundations of all of physics. It was fairly abstract at the time, but subsequently led to transistors, lasers, superconductivity, light-emitting diodes, and everything we know about nuclear power (and nuclear weapons). Without this basic research, our world today would look like a completely different place.

Even general relativity, Einstein’s brilliant theory of space and time, turns out to have down-to-earth applications. If you’ve ever used a global positioning system (GPS) device to find directions somewhere, you’ve made use of general relativity. A GPS unit, which you might find in your cell phone or car navigation system, takes signals from a series of orbiting satellites and uses the precise timing of those signals to triangulate its way to a location here on the ground. But according to Einstein, clocks in orbit (and therefore in a weaker gravitational field) tick just a bit faster than those at sea level. A small effect, to be sure, but it builds up. If relativity weren’t taken into account, GPS signals would gradually drift away from being useful—over the course of just one day, your location would be off by a few miles.

But technological applications, while important, are ultimately not the point for me or any of the experimentalists who spend long hours building equipment and sifting through data. They’re great when they happen, and we won’t turn up our nose if someone uses the Higgs boson to find a cure for aging. But it’s not why we are looking for it. We’re looking because we are curious. The Higgs is the final piece to a puzzle we’ve been working on solving for an awful long time. Finding it is its own reward.

Excerpt from THE PARTICLE AT THE END OF THE UNIVERSE © 2012 by Sean Carroll. Published by Dutton, A Member of Penguin Group (USA) Inc. Excerpted with permission from the publisher. All Rights Reserved.