So for some years I've been dimly aware that Science [TM] has been building a particle accelerator the size of a city.
Whatever. Those wacky scientists!
Excitement has been building around the world over the last few months, because they've spent more than twenty years building the thing, and they finally get to switch it on this week. Ok, that's understandable. But when people I know are calling it things like this generation's man-on-the-moon, some part of me wonders if perhaps I should be paying more attention.
So little by little, I start paying attention. And every time I do so - every time
- I learn something that floors me.
As you probably know, it's called the Large Hadron Collider, or LHC, and for a start, the project is of a scale normally reserved for science-fiction. It reminds me of that gigantic structure from the movie Contact:
but really, the LHC is even more massive and more impressive, and seemingly abounds with vistas and structures like this:
Now, that's a pretty big thing to be focusing on something as small as sub-atomic particles. So what does it do?Check out the Large Hadron Rap
on Youtube - it's fun and catchy, and explains a lot. (And I'm secretly wondering if I could convince a DJ to play it at one of the nightclubs here)
So take twenty-seven tonnes
of electro-magnet. Now multiply that by over a thousand
- there are ~1600 such magnets in the LHC.
But that's not enough. To get field strengths of the magnitude needed, all of those magnets need to be turned into superconductors. As you probably know, superconductors need to be so cold that liquid nitrogen is often used to cool them, because its temperature is lower than negative 351 degrees F.
But that's still not enough. Liquid Nitrogen would still be over a hundred degrees too hot. They need to cool these things to less than two degrees above absolute zero!
If there is a fault in any sector of the LHC, then it has to be shut down for maintenance. But it takes over a month to warm up the section to the point where maintenance can be performed. And another month after that to get it cold again afterwards. So when things go wrong, the facility is down for at least two months.
This facility draws enough energy to power up to 180,000 US homes.
Of that, enough energy to power twenty two thousand homes
goes into the experiment (and that's not counting the cryogenic refrigeration keeping everything cold, the power consumption of that A-C unit could run another 27,000 homes).
So what happens when you focus that much energy into an atomically-tiny area?
No doubt you've heard the fears and lawsuits that this is enough energy to create miniature black-holes that could destroy the earth. (Studies were conducted to evaluate this risk, concluding that the project will not destroy the world, but that it even needed to be studied has resulted in a lot of attention - and fun - check out the on-site web-cams
The amount of energy a particle has is measure in electron-volts, ie "eV". (So, 1eV is how much energy an electron would gain if you accelerated it with an electrostatic potential difference of one volt. It can be used various ways, but think of it like kinetic energy - more eV in means a particle moves faster, and a particle with a large mass moving fast will have more eV than a lighter particle moving the same speed)
And if you are reading this on a CRT monitor, you are staring at a particle accelerator - the image on a television or monitor is created by phosphor on the inside of the glass being struck by high-speed electrons. The electrons impart some of their energy, which the phosphor turns into light.
Your television might impart 25,000eV to particles, and that is enough that your television will light up your room at night. But LHC is bigger than your TV, so we have to go higher.
Radioactive materials can emit Gamma radiation, which can have a wide range of energy. Certainly enough to mess with your DNA. At 50,000eV, cancer can be a concern, or in higher doses, burns, all the way through.
Radioactive materials can also emit alpha particles. These are big and energetic enough to make a puree of your DNA that is visible under a microscope. These guys often have about 10,000,000eV.
The linear particle accelerator of the LHC gets protons up to 50,000,000eV.
Cataclysmic astronomical events can create particles above 100,000,000eV, where you start to get Muons forming when they hit something (such as our atmosphere). I have built a muon-telescope. A muon telescope is not optical, but I guess it's called a telescope because you use it to look at space - cosmic radiation. Cosmic radiation is pretty much all you can see with it because earth-sources like radioactive materials here on earth just can't impart that much energy to particles. Nuclear reactors can't do it. Not even nuclear bombs can impart that much energy
. Thermo-nuclear (fusion) bombs can't produce muons either, though they're getting up there.
The LHC takes those 50,000,000eV protons, and feeds them into its Proton Synchrotron Booster, which gets them up to 1,400,000,000eV. Orders of magnitude greater than nuclear fusion.
Then they are boosted to 26,000,000,000eV
Then they are boosted to 405,000,000,000eV
Then they are boosted to 7,000,000,000,000eV
(This is as much kinetic energy as small things in motion that we can touch and see - and feel if they hit us - but it's all concentrated into a sub-atomic particle, with millions upon millions of times less mass. And all particles in the beam have that kind of energy.
And peak collision energy for some of the ion experiments is...
That number just doesn't mean anything to me. That's the kind of number that you can't hold in your head - the kind of number that if it ever actually existed, you'd expect it to unravel the very fabric of the universe.
And that, of course, is the point.
As you can tell from how I have written this, to me, the results and progress that this facility will bring to my life are only half the story. That a project so ambitious is being undertaken at all, that is something in itself. In a world of wars by choice, corruption, cruelty and indifference, it's so refreshing to see humanity united, and reaching boldly for tomorrow.
--- ---I can (more or less) explain how a computer works at the software level, and I can explain how the software works at the hardware level, and I can explain how the hardware works at the circuitry level, and I can explain how the circuitry works at the semiconductor/component level, and I can explain how components and semiconductors work at the atomic level, and I can explain how the atoms work at the sub-atomic level, but beyond this I get fuzzy, and if you drill down too much at any stage, things quickly get very complicated. However I think in this particlar post, if I've made any mistakes or over-generalisations, probably only pfcblogshere will notice. I don't think Cafe reads my LJ :-)
"OMG!" gasped a proton, "I've lost an electron!"
"Are you sure?!" asked the neutron.