The Large Hadron Collider (LHC) is a particle accelerator under development by CERN, the world's largest organization devoted to particle physics. A particle accelerator, sometimes called an "atom smasher" by lay people, is a device that propels subatomic particles called hadrons at high speeds. Machines such as the LHC make it possible to split particles into smaller and smaller components in the quest for the identification of so-called elementary particles, from which all matter and energy might derive.
The LHC, located at CERN headquarters, is scheduled to begin operation in 2008. In operation, the LHC is expected to replicate, on a miniature scale, the conditions existing in the universe a tiny fraction after the Big Bang. Thus, it may be possible to discern what happened in the early evolutional stages of the universe. Among other things, the LHC may yield evidence of further dimensions beyond our familiar four (three spatial dimensions, plus time).
The LHC is expected to help physicists, astronomers and cosmologists answer questions about the nature and origins of matter, energy and the universe. For example:
- Is antimatter simply a "mirror image" of matter or is the relationship more complex?
- Why does matter seem to predominate over antimatter in the universe?
- Why didn't all the matter and antimatter combine long ago, converting the whole universe into energy?
- What is the nature of dark matter?
- Why do only some particles have mass?
The LHC will use intense magnetic fields generated by superconductivity to accelerate hadrons in a circular path 27 kilometers (about 17 miles) in circumference. The particles will interact with the magnetic fields to gain energy with each revolution. The LHC will be capable of accelerating protons to energy levels of about 14 TeV (trillion electronvolts, where a trillion is equal to 10 12 ) or 2.2 x 10 -6 joule. Nuclei of lead atoms will be accelerated to speeds sufficient to cause collisions having energy levels near 1150 TeV or 1.8 x 10 -4 joule. The electronvolt (eV) is the amount of kinetic energy gained by an electron passing through an electrostatic field producing a potential difference of one volt. The joule is the standard unit of energy, equivalent to a watt - second.