What is the LHC Trying to Accomplish?

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The Large Hadron Collider (LHC) is the most complex physics experiment ever constructed. Located underground, straddling the French-Swiss border, the 27 km-long ring of electromagnets is designed to accelerate protons and heavier charged particles to speeds close to that of the speed of light. The LHC is located at, and managed by, the European Organization for Nuclear Research (CERN).

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As of March 30, 2010, the LHC began high energy collisions, attaining collision energies of 7 TeV, three times higher than ever before.

What will it do?

At strategic points around the accelerator ring, counter-rotating “beams” of accelerated particles are steered to collide head-on by the most precise electromagnet technology on Earth. At these collision points, huge particle detectors are located to track and measure the resulting high-speed smash-up.

When the LHC runs at full capacity, the energy conditions shortly after the Big Bang will be recreated for a very short period of time. This is the reason why the LHC is often dubbed the “Big Bang machine.”

Making these highly controlled mini-Big Bangs allow physicists to have a glimpse at what our universe is made of, creating particles that the universe hasn’t seen since its birth, 13.75 billion years ago.

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What will it discover?

The LHC will probe the limits of physics theory, possibly turning up evidence for the elusive Higgs boson or uncovering the nature of mysterious “dark matter” that is thought to dominate the cosmos. It is, however, the Higgs boson that is the prime focus of the particle accelerator’s mission.

The Higgs boson is the “exchange particle” that is theorized to give stuff mass.

Without the Higgs particle, the universe cannot exist, but if the Higgs particle isn’t discovered by the LHC, it means our understanding of how the universe works is wrong. The non-discovery of the Higgs would be as profound as its discovery, potentially revolutionizing physics.

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What’s the plan?

By the end of March 2010, LHC scientists hope to push accelerated protons to record-breaking speeds, topping an energy of 7 trillion electron volts (an electron volt — or eV — is a unit of energy used by physicists when describing the kinetic energy of subatomic particles).

The LHC initially broke the world record in November 2009 when accelerating protons to an energy of 1.18TeV. 7TeV will be 3.5 times more powerful than its nearest competitor, Fermilab’s Tevatron in Batavia, Ill.

As this experiment is very complex, long periods of “down time” are required for CERN scientists and engineers to upgrade and repair the “Big Bang machine.” Although a recent BBC article alluded to some kind of unexpected shutdown at the end of 2011 for a year, this is actually standard operating procedure.

According to a March 10, 2010, CERN press release:

Traditionally, CERN has operated its accelerators on an annual cycle, running for seven to eight months with a four- to five-month shutdown each year. With the LHC, things are different. Being a cryogenic machine operating at very low temperature, the LHC takes about a month to bring up to room temperature and another month to cool down. A four-month shutdown as part of an annual cycle no longer makes sense for such a machine. That’s why CERN decided at the end of January 2010 to move to a longer cycle with longer periods of operation accompanied by longer shutdown periods when needed.

So, the LHC is scheduled to run at half power until the end of 2011 when it will be upgraded to operate at full capacity.