Physics on the Brink

But such a radically shocking result as a completely unexpected particle, while possible, is not the likeliest scenario. A much more plausible outcome, and one that is really stirring up the physics community, is that the LHC will finally shed some light on one of the great modern cosmological mysteries: dark matter.

Only four percent of the universe is made up of the matter we know and love, the stuff of the earth, the sun and the stars. A whopping seventy percent is comprised of mysterious dark energy, which is causing the universe to expand. And the remaining twenty-six percent is dark matter—we can’t see it, but gravity tells us it is there. Without dark matter, galaxies would fly apart, spinning to pieces under their own inertia. Dark matter is massive, it’s all around us, but we haven’t figured out how to interact with it so we have no idea what it actually is.

Physicists are optimistic that the LHC will change that, however. When particles in the LHC collide, they will reach the temperature of the very early universe (about ten thousand trillion degrees centigrade—a billion times hotter than the center of the sun), when many cosmologists think dark matter was probably created. They hope that recreating the conditions that existed only a trillionth of a millisecond after the big bang will allow them to glimpse dark matter for the first time.

“That would be huge because dark matter is the second biggest component of the stuff of the universe. We would start knowing what the universe is made out of,” says Weiner. “There’s a great shot that it can be made and when it is, we’re going to have a lot of fun trying to understand it.”

Our Coliseum

Physicists like to tell a joke about a man who has lost his keys, and is searching for them on the ground under a streetlight. A kind stranger notes his plight and offers to help, and after thoroughly scouring the area to no avail, asks, “Are you sure you lost them here?”

“No,” says the first man, “I lost them over there.” He points somewhere off in the darkness.

“Then why on earth are you looking for them here?” asks the exasperated stranger.

“Because this is where the light is!”

The universe is a very dark place. Physicists often do not even have the luxury of knowing what they are looking for. Keys are easy—we know what they look like, feel like, how big they are and how much they weigh. The answers physicists hope to find, however, can come in bizarre, unpredictable packages. Their only hope is to look in the light—use whatever tools and technology are available to thoroughly scour any illuminated patches of ground.

Turning on the LHC will be like suddenly shining a floodlight on a hitherto dark corner of the landscape. Physicists don’t know what they will find, but they’re sure it will be exciting. And they’re also sure it will bring science closer to answering that most fundamental question: Why are we here?

“When I think about what civilization has accomplished, I really think that this knowledge is sort of like our coliseum, our pyramids. But instead of structures, our big achievement will be to understand our universe,” says Weiner.

Mincer agrees. “I can’t imagine a greater intellectual achievement than to think we have finally figured out something we have been asking for thousands of years. If we can do this, I can’t imagine how something could possibly beat it.”