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Large Hadron Collider fires first beam.
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The Large Hadron Collider (LHC) passed its first real operational test today by successfully herding a beam of protons all the way around the 27 kilometer ring lying 175 meters below the border between France and Switzerland. In fact, the first test was so successful that they fired another beam around the other way - proving the capacity to generate two counter-circulating beams of protons, which will ultimately be guided into collision with each other inside of one or another of the various detectors located around the ring.
Diagram of the LHC showing temperature of the components - here the whole ring is down to 1.9K
The two beams were not accelerated anywhere near to the speeds the device is capable of attaining - this was primarily a test of the ability simply to guide the beam all the way around the track via an array of supercooled superconducting magnets distributed around the ring. The whole system has been cooled over the last several months to a temperature within 2 degrees of absolute zero to bring the magnets into the superconducting regime - where electrical resistance drops to zero and much higher strength magnetic fields can be generated with much less power than with conventional electromagnets.
Image of the first proton beam from the ATLAS detector
In the coming months, scientists will carefully bring the LHC up to full capacity. The next crucial test will be their ability to "grab" the photons magnetically and concentrate them in small, tight packets. Next, they will accelerate these packets around the ring multiple times, ultimately reaching speeds of approximately 0.999999 times the speed of light.
Finally, by colliding together two such highly accelerated, counter-rotating packets, the LHC will yield particle collisions of unprecedented energies, opening up a whole new world of high-energy physics experiments (and not, by the way, destroying the Earth in the process - see the bad astronomer's rant on this topic here)
The results expected within the first year include definitive experimental answers to such questions as the existence of the Higgs boson (the particle hypothesized to be responsible for mass), the reason for the imbalance of matter and antimatter, and the nature of so called "dark matter," thought to compose approximately 22% of the mass of the universe (with ordinary matter making up about 4%, and the mysterious "dark energy" making up the remaining 74%). Also, the LHC may help clarify the number of dimensions that the universe is actually made up of, making some of the predictions of string theory accessible to experimental test.
The physics world is in a state of high excitement about the imminent answers to long posed fundamental questions. Of course, with new data will come new questions, and the need to build even larger and more powerful accelerators. For now, however, physics has a grand new knowledge generating tool that will generate showers of surprises and particles of insight for decades to come.
A couple of great introductory videos to the LHC:
Conventional tutorial
Rap tutorial (text here)
For more information:
LHC Home Page
BBC Introductiion
CERN LHC site
(Note: this is the first of two posts on the LHC - I'll post the second one Thursday morning, after I hear string theorist Brian Greene's lecture tonight at the San Francisco Jewish Community Center.)
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