Starts With A Bang!

Why build an accelerator?

I was at home earlier this week, and I got a surprising question from Jamie (my wife):

If Fermilab scoops the LHC and finds the Higgs, and then the LHC doesn’t find anything will it be a total waste, and why should anyone ever build another huge accelerator again?

From a scientific point of view, Jamie is absolutely right. Our model of what the fundamental particles are in the Universe is pretty complete: we know how to make up all the normal matter in the Universe and we know all the particles that govern their interactions.

The only standard model particle left to be confirmed is the Higgs; we’ve already discovered everything else. Yes, there are other mysteries out there that the LHC might shed light on, including what dark matter is, why neutrinos have mass, whether there may be supersymmetry or extra dimensions, whether any of the standard model particles are made up of smaller, more fundamental ones, or whether there’s an alternative to the Higgs.

But let’s put all the physics (which I’m, of course, partial to) and all the possible scientific discoveries aside for a minute. These accelerators are really, really expensive. To build and operate the LHC, the total cost of all the experiments will top out at somewhere between 5 and 10 billion dollars. That even makes this guy look like he’s asking for peanuts:

There is a lot of good in my country and in the world that can be done with that kind of money. Some outstanding charitable domestic and international organizations include:

• KIVA: which provides loans to entrepreneurs in the developing world.
• WFP: the United Nation’s World Food Program designed to eradicate world hunger.
• Pathfinder International: providing reproductive health education worldwide.
• The Conservation Fund: The number one environmental conservation organization in America according to the American Institute of Philanthropy.
• Big Brothers Big Sisters of America: The number one youth services organization in America.

So how do I justify spending all of this money on building a particle accelerator when so much good could be accomplished by spending this money in other ways?

Even if the LHC never finds a thing, the research and development that has gone into data management will lead to computing and computational advances that have been unheard of. This has happened historically; back in December of 1990 the world wide web was invented at CERN for the sharing of computational information for scientists working at particle accelerators. (Note: you can get knighted for developing stuff like this!) Let’s talk about some of the computing advances that are already happening because of the LHC.

The Worldwide LHC Computing Grid links over 100,000 processors, 7,000 scientists and 33 countries to the LHC for analyzing data. There will be massive amounts of data pouring out of the LHC, as it needs to track and write the full detector data for over 100 collisions every second. That doesn’t sound like much, until you realize that each collision sets off 7,000,000 bytes of data. Since the LHC will be taking data continuously for about a decade, that’s enough data that if you burned it to CD-ROM and stacked it, it would reach 180 km in height, or almost high enough to collide with the International Space Station. That’s a lot of data to sift through and meticulously analyze, looking for a tiny, complex signature of new physics.

So the analysis of this data, looking for literally millions of possible signatures and configurations for each collision, is a fairly mind-boggling computational task. But the LHC had an even bigger one to face. You see, the LHC doesn’t have around 100 collisions per second. It has 600,000,000. So what do you do to filter the 600,000,000 collisions down to the 100 or so good ones that contain important data?

You build the two biggest detectors ever assembled with the most sophisticated electronic triggering system ever imagined. This hardware looks for important signatures that indicate new physics, and makes decisions in stages, every 25 nanoseconds. 600,000,000 collisions are pared down to about 100,000 before the data ever sees software, as hard-coded electronics just reject over 99.9% of the events that don’t set off the right triggers. Some of those systems are found inside of these detectors, and the individual parts look something like this:

Want to know how much faster and better the LHC computing technologies are in terms of speed and volume? Check out what they’ve managed to accomplish on this graph:

So even if you don’t find anything, the LHC has already succeeded in creating the most advanced computing and data-taking processes in history in many different regards. In the past, computational technologies developed at particle accelerators have lead to such scientific advances as lasers, cellphones, magnetic resonance imaging, nuclear power, and the computer, in addition to the world-wide web. The director of CERN has a lot to say about this, if you don’t want to just listen to me ramble. So I’m all for physics and scientific discovery on the wonder of its own merit, but don’t forget that lots of practical uses come out of these, also! What new technologies will come decades down the road from the LHC? Perhaps… teleportation?

I’m sure if it’s possible, we’ll work the bugs out! Oh right, and don’t forget to check out this week’s Carnival of Space, where we’ve got a great entry comparing humans to galaxies, and look at what they’re both made up of.