Saturday, 23 February 2008

Large Hadron Collider

The Large Hadron Collider (LHC), currently under construction on the Franco-Swiss border, will be the largest and most powerful particle accelerator ever built. More than 80 countries are involved in this mammoth project. It will usher particle physics into the terascale era, reaching energies above 1 TeV or a trillion electron volts. It is hoped the LHC will shed some light on some of the biggest mysteries in particle physics.

The LHC is a 27km circular tunnel located 100 metres under ground. Protons will be sent hurtling down this tunnel at almost the speed of light. The beams of protons will then smash together, 30 million times a second, spewing out thousands of exotic particles. Among those, physicists hope to find the elusive Higgs boson. This hypothetical particle is believed to give other particles mass. According to theory, the universe is filled with something called the Higgs field, disturbances in this field as particles move through it cause objects to have mass. It is the only Standard Model particle not yet observed. The discovery of the Higgs boson may help explain the the gravitational force is so weak compared to the other forces and it would also be a significant step in the search for a Grand Unified Theory.

Other important areas of research include:

One of the most interesting sections of the wikipedia article on the LHS is about the safety concerns. One of those concerns is about micro black holes, some extensions of the Standard Model predict that the LHC will be able to create micro black holes. Now, according to the Standard Model these black holes should decay away very rapidly due to Hawking radiation, however Hawking radiation is still debated among physicist and it is not yet experimentally verified. So it is possible that these tiny black holes accumulate and eventually devour the earth. The other concern is strangelets. These are hypothetical form of matter that is more stable than normal matter. If strangelet come into contact with the earth (or any other matter) it can convert that normal matter into strange matter.

I would not lose any sleep over these concerns if I were you. We already know that cosmic rays can have energies greater than 1020 eV, far larger than anything the LHC can produce, and we have yet to detect any strangelets or black holes appearing from nowhere. There is a far greater probability of you dying from putting your pants on than any strangelet.

The LHC is expected to start operation in May 2008.



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