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  • If you have even the slightest interest in science, by now you've probably heard of an

  • exciting new scientific facility called the Large Hadron Collider or LHC. But what do

  • you know about it?

  • Well first, the LHC is a particle accelerator. It is located at the CERN laboratory in Europe,

  • just west of Geneva, Switzerland.

  • This accelerator takes two beams, each containing about 300 trillion protons, and shoots them

  • at one another. Even though there are lots of protons in the beams, individual collisions

  • are only between two protons, one travelling in one direction and one travelling in the

  • opposite direction.

  • For the subatomic world, these protons have an enormous amount of energy, although from

  • a human perspective, it's really very small... about as much energy as a mosquito flying

  • at full speed. However this energy is concentrated into an incredibly small volume. The result

  • is that when the protons collide, they experience temperatures of tens of trillions of degrees

  • centigrade, which is over a hundred thousand times hotter than the center of the Sun.

  • In order to get a feel for what those conditions are like, we could ask if we wanted to make

  • a ball the size of a basketball with that energy density, how much energy are we talking

  • about? The answer is simple. A lot.

  • And I'm not kidding. It would take the energy of the Sun itself. And I'm not talking about

  • the energy of the Sun hitting the Earth, I'm talking about all of the energy of the Sun.

  • And not just for a second, a minute, a day or a year. If you could take the entire energy

  • output of the entire Sun for over 20 million years, and concentrate that energy into the

  • size of a basketball, that's what it's like in the center of an LHC collision.

  • Studying matter under these incredible conditions allows us to learn what the universe was like

  • a tenth of a trillionth of a second after the Big Bang and to work out some of the most

  • fundamental rules that govern the universe. And we've already had a huge triumph. In July

  • of 2012, we announced the discovery of the Higgs Boson, which was the last missing piece

  • of our current best theory of the laws that govern the universe. When the 2013 Nobel Prize

  • in Physics was awarded to Peter Higgs and Francois Englert for the prediction of the

  • Higgs Boson, the entire scientific world basked in their glory.

  • Of course, even with such a momentous discovery, we're not done. I mean, if you're in a mine

  • and you find a huge nugget of goal, you don't stop. You keep digging. And LHC scientists

  • are doing just that. After taking data from 2010 to late 2012, the LHC was temporarily

  • shut down for refurbishments, retrofits and upgrades. The Spring of 2015 is the beginning

  • of a new period of data taking that is expected to run for several years.

  • Even better, the new and improved LHC really is that- new and improved. It will collide

  • particles at over 150% the energy it did before and with far more collisions per second. With

  • these enhanced capabilities, scientists will look for all sorts of things, hoping for a

  • discovery.

  • You might ask "what are we going to find?," but that's really a very silly question. After

  • all, the LHC is a machine of discovery. To paraphrase a famous scientist, if we knew

  • what we were going to find, it wouldn't be called research.

  • But we do know what we're going to look for. We're going to look for supersymmetry, extra

  • dimensions, precision tests of our existing theories and deeper investigations into the

  • properties of the Higgs boson, and maybe even make the dark matter that astronomers say

  • is five times more prevalent than ordinary matter.

  • And, of course, we'll be scouring the data looking for something entirely unexpected.

  • That would be the coolest outcome we could hope for.

  • There's another interesting aspect of the LHC. For those of you who might not have a

  • scientific interest but are fascinated by engineering, the LHC is an outrageous accomplishment.

  • The LHC is a ring about 17 miles in circumference: 27 km. The beam travels around the ring about

  • ten thousand times a second. To guide the beam in a circular path takes 9600 magnets,

  • of which 1232 are especially strong. These magnets, called dipoles, use about 11,000

  • amperes of current to make a magnetic field 160,000 times stronger than the Earth's magnetic

  • field. The energy stored in the magnets is 11 billion joules. That's enough energy to

  • melt fifteen tons of copper.

  • When the beam is put in the accelerator, it circulates for a long time, say about 10 hours

  • or so. During that time, the beam travels far enough to go to Pluto and back.

  • In order to have a beam travel that far, the beam is kept inside a pipe that is under high

  • vacuum. The vacuum is ten times better than the surface of the Moon. And the total volume

  • in the beam pipe is about the same as one of Europe's majestic cathedrals.

  • And if all those numbers weren't enough to blow your mind, the center of the magnets

  • are cooled to incredible temperatures, to 1.9 Kelvin or 456 degrees below zero Fahrenheit.

  • By any definition, the LHC is a spectacular scientific achievement. And the thing that

  • makes the whole endeavor so incredibly exciting is that the experiments we do might discover

  • something entirely new and change our entire understanding of the universe. We'd have to

  • rewrite the textbooks. But you know, I am totally up for that. How about you?

If you have even the slightest interest in science, by now you've probably heard of an


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LHC: 大型ハドロン衝突型加速器 (LHC: The Large Hadron Collider)

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    richardwang に公開 2021 年 01 月 14 日