Showing posts with label LHC. Show all posts
Showing posts with label LHC. Show all posts

Thursday, 4 September 2008

Science Goes Boom: The Large Hadron Collider

Update 10 September 2008: Well, the world is still with us. The LHC has powered up and run a successful one-way test collision. We live to collide another day. The real experiments are due to begin on October 21st so I expect we shall hear more from the panic mongers. But for now, every-day scientists, a funky-looking picture (the first data produced by the LHC).


Author's note 04 September 2008: Beaten to the punch! A geologist friend of mine suggested an article debunking the LHC panic a few weeks ago, but I thought it more appropriate this week. The Short Sharp Science blog (1st September) however, has pretty much pre-empted my own commentary, practically down to the last point. Here's my take anyway.

On the 10th of September, if Dr. Walter L. Wagner is correct, there’s a pretty good chance that the world is going to end. Or at least begin ending. On that day, the scientists at the Large Hadron Collider (LHC for short) will power it up and perform their first experiments. The LHC is a particle collider, a giant ring tube, 27 kilometres in circumference and buried beneath the Swiss countryside at a depth of about 50 to 100 meters. The point of this ring, as the name suggests, is to collide particles. Particles can be atoms, the building blocks of all matter, or even pieces or these. The particles are launched into the ring tube in opposite directions. Large electro magnets keep the particles traveling along the same line inside the ring and ensure that they follow the curve of the ring around to the far side. At the far side, the particles collide. When this happens, the particles effectively explode on a tiny scale, producing new and even smaller particles. This effectively replicates the sorts of collisions that occur between cosmic rays and the upper atmosphere of the Earth.

The collision is timed so that it happens just as the particles enter an enormous eight-storey-tall detector (pictured to the right). There are already many devices like the LHC in the world, and they’ve taught physicists a whole lot about the un
iverse, but the LHC is different. It’s the biggest particle collider to date, and it can throw the particles out with greater energy than any device previously built. In fact, the LHC will propel tiny particles about 1x1025th (that’s 1 with 25 zeros after it) the size of a grain of sugar, with the same energy as a high speed train. The goal of this €5 billion project is to test the current major hypothesis in physics, the Standard Model. This includes the search for a particle that has been predicted to exist by our current understanding of physics, but which has never been observed; the Higgs boson, the particle that is thought to give all matter its “weight” or more correctly, its mass.

If these collisions are so very common in the atmosphere of Earth, why bother with the LHC at all, you might ask? The answer is in that eight-storey tall detector. Not an easy thing to lug around, let alone fly into the atmosphere. And since we can never predict where a particle collision may naturally be about to occur, we would have no chance to move the detector to the correct spot, let alone line it up so that the collision happened exactly at the centre of the detector. The far more sensible option is to bring the particles to us, which is what the LHC is for. If the experiment fails or succeeds, it might well usher in a paradigm shift in physics.

Doomsday

The problem is that some hypotheses about the universe predict that we’ll find something much less pleasant than the Higgs boson in our detector. Amongst the suggested doomsday outcomes of the LHC experiments are the creation of stranglets, magnetic monopoles and, Dr. Wagner’s favourite, mini black holes. It’s unlikely that most people (including me) will know what those first two things are, but pretty much everyone has heard of black holes. And pretty much everyone knows that they are, to put it mildly, A Bad Thing. And it’s black holes that are what Dr. Wagner is warning the world about. If formed, Wagner predicts, such tiny black holes would not be detected at first. They would zoom right through the LHC (they’d be too small to interact with matter) and off into space, at least for a while. Caught in the gravity of Earth, a micro black hole would fall back and right through the planet before flying into space again. This might happen a number of times before the black hole starts to collect matter, and starts to slow down as it does so. Eventually, it would settle down in the core of the Earth. And there, it would literally swallow the planet in just over two years. We would probably figure out that something had gone wrong when the earthquake would start. Things would get very nasty very quickly after that, and it is unlikely that anyone would survive to see the actual imploding death of Earth itself.

Scary stuff, and with that kind of story making the rounds, it’s little wonder that some people are calling for the LHC to be stalled, shut down or destroyed. The tinfoil hat brigade on the internet (conspiracy theorists), are out in force and claiming that the LHC is in fact a weapon to destroy life on Earth. A story that has something to do with aliens seems the most popula
r motive for such an expensive way to do a job that could be more cheaply and easily performed with a few nuclear warheads.

But let’s take a step back from Crazyland for a moment and take a look at what the scientists who started the controversy are actually saying. They’re not actually claiming that the LHC will cause catastrophe, but rather that it might. Nor are they calling for the dismantling of the LHC, but rather for an injunction to stall experimentation while safety assessments are carried out. Further safety assessments, that is. A major independent safety review already concluded that the LHC was safe in 2003. Another review confirmed this in 2008, and that review was double checked by yet another independent scientific council. Two groups of physicists have also published peer-reviewed papers backing up these claims of safety. So the majority of the science brigade stand on the side that says everything is going to be okay. And the critics are not even sure that they’re right. The problem for those of us outside of physics (and The Biologista is very much unsure what a Higgs boson actually is), is that the portents of doom, and the defences against these, are delivered in very difficult physics-speak.

Look up


So how do we satisfy our scepticism and sooth our, let’s face it, fear? There is on easily palatable piece of scientific knowledge that can put our minds at ease. The collisions that will take place in the LHC in these coming years have already happened countless trillions of times all around us, or more specifically, above us. As I already stated, the upper atmosphere is constantly bombarded with particles from space. These particles are of all shapes and sizes and impact at energies that are higher than anything the LHC can produce. Indeed, even stronger impacts than these occur around neutron stars and white dwarf stars. And these bodies have such a huge gravity that any possible micro black holes formed would surely not escape to space but would come to rest within the stars, gobbling them up from within in a spectacular and frightening manner. Given how often such collisions take place that ought to mean we’d see loads of white dwarfs and neutron stars popping their celestial clogs left right and centre. But we don’t. In fact, we never have.

It could also be said that at a certain point we have to have, I hesitate to use the word, faith in the physicists. I can feel fairly certain that the very clever employees at CERN, which hosts the LHC, would rather not die. And despite media portrayals to the contrary, scientific experiment
ation has a great safety record. The Mad Scientist bringing doom due to his meddling with nature is a myth based more upon the failings of the products of science in the hands of others than on the actual practice of research itself. Three Mile Island and Chernobyl were built upon scientific knowledge, but they exploded in ignorance of science.

Whilst we might doubt the motives of military research and commercial research such as the big pharmaceuticals companies and the nuclear industry, the LHC is something quite unique. You see, there’s no direct commercial or military benefit to it at all. On the contrary, the LHC represents the rarest of things in modern science; billions of euros spent in the pursuit of... knowledge. Nothing more. In June, Wagner’s case in the US was dismissed, and a similar case brought in the EU was dismissed just last week.

Trillions of natural test runs in our atmosphere, numerous independent safety reviews, two peer reviewed defence papers, the survival instinct of scientists and above all, a noble goal. Perhaps I’m naieve
, but that’s good enough for me.