The Large Hadron Collider Is Back in Business!

Over the weekend, the huge Large Hadron Collider—the world’s most powerful particle accelerator and collider—became even more powerful. After a two-year hiatus in research to perform upgrades, the LHC is once again up and running and is now able to accelerate subatomic particles to even higher velocities than before.

In 2012, scientists using the LHC announced the discovery of the Higgs boson, a subatomic particle that is indirectly responsible for other particles having mass. This was a huge achievement; the particle had been predicted for decades, but no collider had been powerful enough to so cleanly detect it.

The LHC works by creating two beams of protons moving in opposite directions around the 27-kilometer-long ring under the ground in Geneva. Using a string of superconducting magnets, the protons are accelerated to just a hair under the speed of light and then directed to smash into each other. The head-on collision is so energetic that new subatomic particles are created (mass in the form of particles can be created by the huge energies involved because, as Einstein pointed out, energy and mass are two sides of the same coin, in many ways interchangeable).

In a sense, they are recreating the conditions that existed when the Universe was just the merest sliver of a fraction of a second old, a mind-numbingly energetic soup of exotic particles. By colliding protons together, the LHC is letting us peer back in time and see how the Universe itself created the reality around us.^*

And now it has twice as much energy. The upgrade should allow scientists to further investigate the Higgs boson (the discovery was amazing, but now it’s time to poke at it harder and see what makes it tick), as well as investigate other phenomena like dark matter, why gravity appears to be so weak, why there’s so much matter and so little antimatter in the Universe, and more.

CERN—the European Organization for Nuclear Research (the acronym is a leftover from an older name)—has a great page about all this with tons of links if you want to find out more.

A few years ago I was thrilled to be invited by my friend Brian Cox to visit the LHC and had a fantastic time poking around in it. What’s hard to grasp is the scale of it; the ring itself is big, of course, but the detectors are unbelievable. Massive. You need a lot of layers and magnets and cables to catch and record every bit of shrapnel ejected from the proton collisions, and that means the detectors are as big as buildings.

My friend and photographer Christoph Malin, along with a team of others, put together a time-lapse animation showing the work done to upgrade the LHC and the ATLAS detector, and it gives you a sense of the scale of the proceedings.

Even this is just a taste of what it’s like. The LHC is the most complicated machine ever built by humans, which is fitting: It’s designed to investigate the underpinnings of the Universe itself and help us understand how all this magnificence came to be. This is perhaps the most noble and wonderful thing we do, and it’s fantastic to see it begin its exploration anew.

^*And yes, it’s safe.

Correction, April 6, 2015, at 13:30 UTC: I originally misspelled Brian Cox's name. Although he has a very useful one, it's not Brain Cox.