What happened when the Universe was created? Scientists working on the biggest experiment in the world are hoping to find out soon, after the relaunch of the Large Hadron Collider (LHC), a giant instrument built deep underground at the European Organisation for Nuclear Research (CERN) in Switzerland. The idea is that it will recreate the clash of particles that happened during the big bang, so that scientists can learn more about how the Universe began.

The CERN scientists are trying to answer a big question, so they need some very big equipment. The LHC is set in a freezing, 27km circular tunnel, as large as the Circle Line on the London Underground. To recreate the big bang, the LHC will shoot beams of protons around the ring, almost as fast as the speed of light. The beams will then collide head-on and break, demonstrating what conditions were like a fraction of a second after the big bang occurred.

There was a big fanfare last year when the LHC was first turned on. But unfortunately, there was a problem — it overheated and broke down during a test run, so the launch had to be postponed.

Now that the LHC has been switched on again, there is a lot at stake. The multimillion-pound experiment will generate temperatures of more than a trillion centigrade: critics say that it could create a black hole and tear the Earth apart! Let’s hope it goes according to plan.

Find out more about science at direct.gov.uk/sciencesowhat

What is the big bang?

The big bang is an idea about how the Universe was formed, and the majority of scientists consider it to be true. They say that 13.7 billion years ago, the Universe exploded out of a very, very, small, dense and hot place. In the first trillionth of a second of its creation, the Universe was ten billion trillion trillion degrees celsius! The bang left behind huge clouds of gases and particles, which, after a billion years, formed the first stars and mini-galaxies. Then, after nine billion years, our planet Earth was formed. But the Universe hasn’t stopped growing — it is still expanding by 43 miles every second.
Olivia de Ferrer

Fact: The LHC contains the world’s biggest freezer. It could hold 140,000 fridges full of sausages

Fact: CERN has its own fire brigade with Bulgarian, British, Czech, Finnish, French, German, Spanish and Italian firemen

Fact: If the LHC works, for the first time in an experiment protons will travel at the speed of light, going around its ring 11, 245 times a second

Bill Bryson meets the CERN scientists in Eureka, in The Times, this Thursday

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