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Writings on technology and society from Wellington, New Zealand

Thursday, September 11, 2008

Some of the tech in the Large Hadron Collider

Today on Radio New Zealand National I talked about the difference between technology and the kind of hard science that the Large Hadron Collider is doing, and about some of the ways technology is supporting that project.

Read on for my speaking notes, or listen to the audio download as ogg or mp3.


Q: What is that?

A: It’s a rap about the Large Hadron Collider. It’s much better on YouTube, where you can see the visuals…

Q: Who made it?

A: A woman called Kate McAlpine. She’s a scientist at CERN where the Large Hadron Collider – the latest and greatest particle accelerator – is about to be switched on. She’s done a four minute YouTube rap, and the science in it seems to be spot on…

Q: And the music?

A: I think that’s in the ear of the beholder, don’t you? But the video is worth a few minutes of your time. Linked today, of course.

Q: You want to talk about the Large Hadron Collider this week. That’s more hard science than you usually talk about?

A: Yes. I’m quite clear about the difference. Technology is the way we do things, its recipes.

Q: recipes? Really?

A: Well, actually, yes. Recipes – in the usual sense of cooking recipes – are technology in my book. You know, you assemble these ingredients and do this to them and out pops something new that you might want to eat. Just like building or using gadgets.

Q: So there’s a recipe to build a mobile phone?

A: There certainly is, or rather, there are hundreds of recipes depending on the type of phone. And there are recipes for how to use them as well. And, like cooking recipes, people change the recipes and come up with new ones, and suddenly instead of prawn cocktail starters and bakelite rotary telephones we have sushi and iPhones.

Q: Sushi has been around for a long time…

A: It doesn’t pay to pick at the analogy too hard or it will bleed. But my point is, that technology is an aspect of culture, it’s the way we do stuff.

Q: And how would you define science?

A: Science literally means knowledge, as anyone who can remember their high school Latin knows. Science is more basic research. Sure, there’s a recipe to build a cell phone, but that recipe only exists because scientific research has built our understanding of physics and metallurgy to the extent that engineers can make a recipe.

Q: So we need the science before we can have the technology.

A: Absolutely we do.

Q: Is that how you justify the money that gets spent on science? What about things that will never be useful?

A: Two things to say about that: first of all, it’s pretty hard to predict what’s going to be useful up front. Pure mathematical research is an often-cited example of something that has no applications; but pure maths underlies the codes we use on the Internet to protect banking transactions. And it helped the British crack the German Enigma codes during the Second World War, which may well have turned the tide of the war. Same argument with the Americans in the Pacific war.

But the other thing as to why we do science – we do it because its fun, for some clever people anyway, to find out more about how our universe, our world, and our bodies are put together. Let’s celebrate the fact the some people are gifted with the intelligence and determination to find things out and make it as easy as possible for them. It just makes the word a better place.

Q: Like Leonardo da Vinci?

A: Absolutely classic example of man whose genius spanned several spheres of endeavour. And, back then, we didn’t separate science from other fields of enquiry, so no-one got onto Leonardo’s case and said – look, you’re paid to invent helicopters or something and can you please stop wasting time with a paintbox?

Q: But modern science is very specialized.

A: It’s sad, but it probably has to be. There is so much scientific knowledge now available that even to hold it all in one head is impossible. To do original work requires a sharp focus. But there’s still serendipity going on where you bring a lot of clever, scientifically-trained people together and let them follow their interests. The World Wide Web, for instance, came out of a computer project at CERN, the giant particle accelerator on the Swiss border. A cynic – someone who didn’t appreciate science – might say that CERN had wasted all the billions thrown at it over the years, but I’d have to point at the World Wide Web and say that paid for all of it many times over!

Q: Pity for them that they didn’t patent the Web

A: Damn good thing they didn’t! Otherwise it would have been monopolized by some large company and never would have taken off the way it has.

Q: Back to CERN, the particle accelerator. What does that do?

A: CERN is an institution which does fundamental research into what the universe is made of. The latest experiment is the large hadron collider – hadrons are a class of elementary particles. Many of the particles we are familiar with are hadrons – protons and neutrons, for instance. They are the type of subatomic particle which have mass. And the collider accelerates streams of these to velocities incredibly close to the speed of light and smacks them into each other to see what happens.

Q: They can’t get faster than the speed of light, can they?

A: No, Einstein said that, and we’ve not proved him wrong yet. Instead, as you put more and more energy into things to make them go faster they just get microscopically closer to the speed of light, but they still have the energy, and it’s the collision energy that interests researchers – they are on the track of a really big particle that some theories predict, called the Higgs Boson. They hope that if they set up a collision with sufficient energy they’ll get a Higgs Boson out of it.

Q: And what is a Higgs Boson?

A: According to a really attractive particle physics theory, called the Standard Model, the Higgs Boson is the one particle that gives everything else mass. If that theory is right, the Higgs explains how gravity links to the other forces we see in nature.

Q: Has it been found yet?

A: Not by the biggest particle accelerator that’s currently running – that’s at Fermilab in Chicago, but the LHC is capable of far more energy. The machine’s first proper run will be in the next few weeks. And, no-one really knows, even if the Higgs exists, just how much energy it’s going to take to make one. And that’s because we don’t know how much one would weigh – you’ve heard of Einstein’s most famous equation – E = mc2 ? That says that energy and mass are the same thing, but that a huge amount of energy is equivalent to a very small amount of mass. That’s how stars like the sun work – they literally burn their mass through nuclear reactions to give out energy. And the LHC is trying to do the opposite – put enough energy into one place and see what can get created.

Q: How do they get these particles moving so fast?

A: Magnets, basically. Not just your little horseshoe ones, either, but ones like you get in an MRI scanner. For those listeners who’ve never been near an MRI scanner in a hospital – they are amazingly magnetic. The staff won’t let anything metallic in the room. There’s all kinds of videos on YouTube of loose oxygen bottles or even hospital gurneys being sucked toward the machine and thrown into it with incredible force. You wouldn’t want anyone to be inside the machine if that happened, which is why they are so careful.

Now, these magnets are superconducting electromagnets. A regular electromagnet works by forcing an electric current around a circular path with creates a magnetic field – it just does, that’s a law of physics – but to get a really strong magnet like we are talking here, you need a huge current which would cook the magnet and anybody near it. A superconducting magnet works the same way with a big electric current flowing in a circle, but the material its flowing through is superconducting – it offers no resistance at all to the electric current. That’s important, because it lets you put a really big current through. The thing about superconductors is that they only work at around ten degrees above absolute zero – that’s spectacularly cold, liquid helium temperatures. So, you have to keep these things very cold. And if a part of the magnet ever gets too warm, the whole magnet suddenly warms with a big bang as all the energy in its electric current is suddenly converted into heat.

Building these magnets – and the whole of the rest of the Large Hadron Collider – is a great example of technology. And they are necessary for the fundamental scientific research which will ultimately lead to more technology. Science and technology are joined at the hip, but they are different things.

There’s an enormous amount more to the technology of the collider. The collider is all underground, in a 27 km ring that spans France and Switzerland. The machines that detect the product of collisions are very high tech, and there are of course computers to die for to analyse the vast amount of information it generates.

Links

As always, you can discuss this broadcast at it.gen.nz.

The Large Hadron Rap on YouTube – go on, you know you want to!

Another YouTube – a superconducting magnet quenching.

The Large Hadron Collider’s home page, and an article about it in the Herald.

Cartoonist XKCD‘s take.

posted by colin at 11:14 am  

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