Third in a series.
TORINO, Italy — The thing about Italy is that it teaches you to go with the flow. Those who cannot are naturally selected out of the population by early heart attacks, emigration or some other process of elimination. Italians who are left are the only ones who can survive their own system. You always hear them saying things like “No problem” and “No worries.” Today is an example of why that Zen-Italian attitude is important.
The Porto Nuovo train station is a grand dame located near the center of Torino. We walk there from our hotel, about 20 blocks through winding streets with flagstone sidewalks. We arrive at the station in plenty of time and look up to see that our train to Milan — where we were to make our connection to Venice — has been cancelled. There is a strike in Milan and the train station there is closed.
We wait in line for the customer service window, where the attendant says my prepaid ticket is worthless. I need to go to a ticket window and get a refund. But this being Friday, the busiest travel day in Italy, they are all closed. The only alternative is to use self-service machines to purchase another ticket going through Bologna. Then, when I get to Venice, I can go to a ticket window and ask for a refund.
I go to the ticket machine lines, and when I get to the front there are not enough tickets left on the train for our party. I book the next available train, which will take us through two other cities and get us in about 8:40 in the evening. Not ideal, but hey, it’s Italy. I go ahead and make the reservation, which, being rush hour, is more than double the price.
But then, just to be sure, I check again. This time the same parameters yield a one-stop route that costs only one and a half times as much. Back to customer service. I have time. Eventually I get the second set of tickets marked cancelled. I will have to get a refund on those later as well. At the machines I buy the third set at the lower price and more advantageous route.
So here I sit, next to a man who has never heard of deodorant, waiting for six hours to pass and writing the post I promised about the Large Hadron Collider at the European Organization for Nuclear Research (CERN) near Geneva.
Dominique Bertola is the bouncing, gregarious head of public information at CERN, and he is a natural born teacher. He has the rare ability among scientists to take the complicated and make it simple and interesting.
This talent is often looked down upon in the scientific community in a sort of naive snobbery. Astronomer Carl Sagan, perhaps the greatest science communicator ever, had a show called “Cosmos” that was seen by an estimated 600 million people around the world. But Sagan was rejected by his peers for admission to the National Academy of Sciences. This division is part of what I am trying to overcome as I globe trot promoting science debates.
Dominique brims with enthusiasm as he shows me the massive equipment.
The Large Hadron Collider is CERN’s new machine for trying to make some discoveries about the underlying nature of the universe. It is located in a donut-shaped tunnel 100 meters or roughly 35 stories below ground. The donut is huge — a whopping 27 kilometers (16.8 miles) in circumference, running under Switzerland and France. It’s filled not with cream, but with vacuum tubes, superconducting busbars, and electromagnets that make up the core of the particle accelerator.
Racing at the proton track
The way the collider works is kind of like a big slot car race track, except instead of slot cars, the physicists use packets of protons that they shoot into a pair of tubes, each about three inches in diameter. The tubes have the air sucked out of them, to a much higher vacuum than on the surface of the moon. They run side by side around the big 27 km circle, and the beams of proton packets race in opposite directions in each tube, until physicists guide them into collisions in the center of four huge detectors — each about 40 meters long by 30 meters high and about 10,000 metric tons (22 million pounds).
The detectors measure the speed and trajectory and energy of the particles produced by the smash-ups.
As you have probably figured out, there’s a bit of a problem. Protons, like any particle, like to fly in a straight line. If you tie a rock to the end of a string, spin it around your head and let it go, it won’t keep going in a circle. It will fly off in a straight line.
To get the protons to fly in a circle, particle physicists at the collider use a very strong magnetic field. They create it with wafers of electromagnetic metal plates stacked one next to the other like radiator fins along the entire length of the tubes. This magnetic field needs to be really strong because the protons are circling the 27km donut at almost the speed of light – so fast that they make about 11,000 revolutions per second.
Cooling down to powering up
To get the magnetic field strong enough to keep them in the perfect center of the tube takes incredible power — CERN uses about the same amount of power as the entire city of Geneva, over 100 megawatts.
The problem is that getting that much power down there creates a lot of heat and resistance in the electric wires. The engineers working at CERN figured out a novel solution. They use a combination of metals that, when cooled to near absolute zero, become superconductors. And all electrical resistance suddenly disappears. The 10,000 amps of electricity that once required cables the size of a linebacker’s thigh can now flow over a busbar the size of a butter knife blade with no power loss or heat.
This “cryogenic” cooling is achieved by circulating liquid helium through pipes that run along next to the electromagnetic plates. Like liquid nitrogen that your doctor uses to freeze a wart, liquid helium is just a few degrees above absolute zero, or minus 271 degrees Celsius (about 456 degrees below zero farenheit).
The I-35W bridge problem
Cooling the collider introduces another problem, though, and this is what led to the famous failure a few days after the collider’s start-up.
Things contract when they get cold. You see this on bridges — for example, the I-35W bridge that collapsed on us in Minnesota: bridges have joints that slide to allow for movement as their metal structures expand and contract with temperature changes. The same goes for the metal that makes up the collider — but at this incredible scale the effect is enormous. As the collider’s 27 km circumference is cooled, it shrinks by a whopping 80 meters (262 feet).
To allow for this movement without breakage, the collider’s engineers built in about 1,800 flex joints every 15 meters or so — tight enough to retain the near perfect vacuum in the pipes but flexible enough to absorb the shrinkage.
At these joints the multiple superconducting busbars are bolted to one another. But one of those thousands of joints was bad. Heat built up and began to melt the busbar. This caused the liquid helium to heat up as well. It turned back to gas, the superconducting effect was lost, all the magnets in several sections suddenly had electrical resistance, they heated up too, the helium blew and the collider crashed.
It’s easy to see in retrospect how this happened. Each system is relatively simple in its parts. But taken all together the collider is the most complex instrument ever built. When something blows it can set off a chain reaction.
After a year of studying the problem, rebuilding, and installing new safeguards, the collider has run continuously. The packets of protons are accelerated by the magnets in opposing directions.
Then the physicists steer the two beams into a head-on collision and whammo!
The protons explode into their constituent subatomic particles, some known, and some unknown.
That is what physicists want to study. They are like two-year-olds smashing matchbox cars into each other at higher and higher speeds to see what parts fly off – but here the knowledge gained can change the world. Discoveries from particle physics have led, for example, to the information age.
But can they get the Italian trains to run on time? Wait — no worries.
Shawn Lawrence Otto is co-founder and CEO of sciencedebate.org. He wrote the screenplay for the Oscar-nominated movie “House of Sand and Fog” and won the Alfred P. Sloan Foundation’s award for best science screenplay for “Hubble.” He also wrote the screenplay for the upcoming film “Dreams of a Dying Heart.” He lives in Marine on St. Croix.