KS3 / KS4 Physics: How CERN helps us understand the Big Bang

Brian Cox:

Here at CERN, the European Organization for Nuclear Research, can be found perhaps the best example of Britain’s scientific legacy.

Below the ground here, around hundred metres below the ground, is the Large Hadron Collider. It's 27 kilometres in circumference. Its job is to accelerate protons to 99.9999 percent the speed of light, at which speed they circumnavigate these 27 kilometres 11,000 times a second. The protons are collided together, at each one of those collisions the conditions that were present less than a billionth of a second after the universe began, are recreated.

By making particles collide and studying the products of the collisions, scientists can glean a new understanding of the structure of the subatomic world and the laws of nature that rule it. The collider was designed to explore some of the biggest mysteries in the universe, including what happened immediately after the Big Bang.

The sheer audacity of it, that human beings might be able to reach back 13.7 billion years to discover how the universe evolved, is breath-taking. And yet, that's what's being done here on an epic scale.

The Large Hadron Collider is the most complicated scientific experiment ever built, but it's still just an experiment like any other.

At its heart there is repeatable process. Teams of people dedicated to making detailed measurements, and comparing those measurements with theoretical predictions. These are simple principles, yet they hold great power.

Half of the world's particle physicists, 10,000 of them, are gathered here because of the tantalising prospects of what they might discover.

Scientist 1:
CERN is now the place to be because everything is happening here.
Scientist 2:
New physics, new stuff, supersymmetry, dark matter.
Scientist 3:
So we're solving problems which are fundamental to all, all people, everywhere.
Scientist 4:
You don't really care where anyone comes from, it's w-, we all want the same thing.
Scientist 5:
And being part of this is just, is just brilliant (laughs).
Scientist 6:
What do I do. I'm going to have to think about that for a second (laughs).

Brian:
But while one or two of them can't remember what they're supposed to be doing individually, as a group the scientists here have made one of the most important discoveries in physics.

In July 2012 it was confirmed that a new particle, the Higgs Boson, had been detected. This elusive piece of the subatomic jigsaw is responsible for the masses of the building blocks of the universe. The particle is named after British physicist Peter Higgs, who worked on the theory some 50 years earlier.

The discovery is a vindication of the ideas behind CERN, but the reason that we can be confident in the discovery is the painstaking effort that has gone into the design of the experiments.

Even to the point of funding two separate teams of researchers analysing exactly the same things, a cross-check so vital that the teams are not allowed to discuss their work even with each other.

My institute in Manchester is part of an experiment about a few hundred metres in that direction called Atlas, it's a collaboration of over 160 institutes from 38 countries, and together we designed, we built and we operate that experiment. Now, if you go several miles actually in that direction over to the other side of the LHC there's another collaboration, it's called CMS and it's run by different physicists.

It was designed, built, and it is operated completely independently from Atlas. But they're both designed essentially to do the same thing, which is to search for new physics like the Higgs Boson. And because these two groups found exactly the same thing everyone could be confident that the Higgs really had been discovered.

All the basic principles of science are put in to action here at CERN. And it is this, the scientific method that gives CERN and all of scientific investigation its power and validity.

Science is one of this country's success stories, many of its important characters are British, and Britain has always been a place where crucial discoveries are made.

Newton's theory of gravity, the form of the DNA molecule, all courtesy of a few small islands in the North Atlantic.But these great discoveries haven't happened by accident. The existence of organisations like the Royal Institution demonstrates that here is a place where inquiring minds are valued, and the apparently unknowable is thought worthy of investigation.

This is also a nation that celebrates curiosity – and combining this curiosity with a powerful method to investigate nature, it has always ensured that British science is amongst the world's best.