The Large Hadron Collider is all about understanding the forces of nature, and it’s on this understanding that our modern technological world rest. You can trace a direct line through the history of physics, from Newton’s gravity, Faraday and Maxwell’s electronmagnetism, Rutherford’s discovery of the atomic nucleus, Eddington’s understanding of the power source of the Sun, and on to the LHC. Everything we take for granted today, from modern medical technology to mobile phones, is possible because we understand how the forces of nature work.
The LHC has been built because our understanding of these forces has shuddered to a halt. The problem lies in understanding the origin of mass in the Universe, which sounds esoteric, but without this understanding we cannot progress. Our current best theory, called the Standard Model of Particle Physics, includes a mechanism for generating the masses of all the particles in the Universe called the Higgs mechanism. This theory predicts the existence of a particle called the Higgs Boson. If the Higgs exists then the LHC will find it, opening a door to a new and deeper understanding of the forces of nature.
What’s happened in Geneva over the last few days has genuinely surprised me, and I suspect many of my colleagues. The LHC is an incredibly complicated machine, and it is very challenging to wake the machine up again after last years’ accident and begin to circulate particles around it, never mind to collide them. I heard an engineer last year say that circulating particles around the LHC was like threading a 27km piece of wet cotton through the eye of a needle with one hand behind your back.
Given that they only switched the machine back on last week, the results we have seen so far have been amazing. I really wouldn’t have expected progress like this until after Christmas - I worked at a particle accelerator in Hamburg in the 1990s and that machine took two or three years to really start behaving itself. So to get particles colliding after a couple of days is breath taking. For once it’s not hype.
Admittedly, we are right at the start of the journey. Energy levels in the collider at the moment are about 0.5 TeV – still a huge way off the machine’s maximum operating level of 7 TeV. CERN are now aiming for 1.2 TeV before Christmas, which will already make LHC the world’s most powerful collider overtaking the Tevatron at Fermilab near Chicago. It’s then a case of gradually increasing the energy to levels around 3.5 TeV, which is the probably the level we’d like for ground-breaking discoveries. I’d expect the machine to hit that sometime in the New Year.
As all this is happening, there will be lots of interesting data for the particle physicists and engineers, allowing them to calibrate their detectors and better understand this wonderful machine. In engineering terms, the LHC is as difficult as going to the moon. The technology is right on the edge, which is exactly where we need to be as a civilization. As just one example, the superconducting magnet technology being pioneered and understood in the LHC today is what you need to build nuclear fusion power stations, which may well be the key to solving our long-term energy crisis.
I would guess that it will be three years at least before the big headline discoveries, like Higgs Bosons or the nature of Dark Matter start emerging. This is the start of a long and exciting road that will last decades. But as JFK said when he launched America on a path to the Moon, we do these things “not because they are easy but because they are hard".
Brian Cox is professor of particle physics and Royal Society university research fellow at the University of Manchester