Cats and Theories
a blog by coticheque
a blog by coticheque

Visiting CERN in Geneva

If you want to get a feeling that the stuff you’re doing at work (or generally in life) is totally irrelevant, just visit the headquarters of CERN in Geneva. This is the place where people are preoccupied with real problems. Not some made-up issues in made-up spheres like law, marketing or finance. No, more serious problems – such as figuring out the origins of the Universe. Or, to put it more precisely – verifying the hypotheses of how the Universe could have happened – mainly the Big Bang hypothesis. Scientists have their own cosmogony.

Esplanade des particules

CERN headquarters are located on a street with a beautiful name – Esplanade des Particules (Geneva is situated in the French-speaking part of Switzerland).

As the street name suggests, CERN is preoccupied with particles. The organic stuff is made out of molecules, molecules – out of cells, cells – out of atoms, atoms – out of nuclei and electrons. Nuclei – out of protons and neutrons. Protons – out of quarks. And quarks? That’s how far we’ve gone yet. Any combinations of quarks are called hadrons. Protons and neutrons are the type of hadrons called baryons. And that’s exactly what the Large Hadron Collider is designed for. It accelerates protons and collides them.

But why to collide? Since we know that E = mc2, and that energy can be directly transformed into mass, colliding particles at enormous speeds is supposed to produce new particles with extremely high masses. Such massive particles include mysterious entities with enigmatic names such as muons, tau, quarks, W and Z bosons and others. Apparently that’s what the Universe was full of in the first seconds of its life. And in the past 10 years of operations, CERN has discovered more than 50 of such new particles.

And speaking of time, CERN is aiming to verify the Big Bang hypothesis, therefore it’s dealing with events happening on an unimaginably short timescale. Things that allegedly happened in the first microseconds after the Big Bang. Before chemical elements were formed, before subatomic particles formed into atoms, and before quarks bound together into hadrons (the ‘quark epoch’!). And all that happened fast. The quark epoch started at 10 at the power of -12 seconds, and ended at 10 at the power of -6. The most important fraction of a second in the history of the world. Only collisions at extreme speeds could potentially recreate the conditions that were allegedly observed during the first seconds of the Universe existence.

Quarks are held together by the force so strong that it’s literally called ‘the strong force’ or ‘strong interaction’. The only way to split them up and rearrange into new hadrons is collisions at enormous speeds. Collisions stronger than the strong force itself. Too bad that most of the new particles discovered by CERN are extremely unstable and decay within seconds.

On a speculative note, if nuclear power arises when protons detach from atom nuclei, what happens when we separate quarks from one another? Maybe one day the strong force will be conquered and ‘domesticated’ for human needs, same way as the nuclear fission was? I bet that’s how intergalactic spaceships are going to be powered 1,000 years from now.

Operations of LHC

In order to recreate conditions comparable to the beginning of the Universe, CERN built the Large Hadron Collider: a circular underground tunnel 27 kilometers long, situated on the border between Switzerland, and France and occupying territories of two countries.

The LHC consists not of one, but of a number of circular tunnels, or rings. First, protons go into LINAC – linear particle accelerator, then Proton Synchrotron, and then… Super Proton Synchrotron (don’t even ask), and only after that into the LHC itself. Fun fact: each system is also used for various side-experiments: for instance, PS is used for analysis of the impact of cosmic rays on… Earth’s cloud formation.

The process starts when hydrogen is supplied into the system, and its atoms are stripped out of electrons, leaving only protons. Why hydrogen? First, it’s the lightest and simplest element out of all, that consists only of one proton and one electron. Second, it was the first element ever formed in the Universe (during the so-called ‘Great Recombination’ epoch; the rest formed much later, many – during the star explosions). As Harlow Shapley allegedly said: Some piously claim that ‘in the beginning there was God’, but I say ‘in the beginning was hydrogen’. And before hydrogen, the Universe consisted only of hot dense plasma of photons and quarks. Protons themselves came a bit later (during the ‘hadron epoch’!), and what happened to primordial photons… Well, we’ll discuss it soon.

Anyway, the protons are then fed into the accelerator, and when the sufficient speed is achieved, they go into the collider. When the proton beam starts, it goes on for around 10 hours. During this time, protons make around 400 million revolutions around the collider ring, and travel the distance that almost reaches diameter of the solar system!

Due to the amount of information produced by CERN experiments (information measured in the smallest measurement units in the world), CERN is running on an impressive IT infrastructure. LHC is producing 90 petabytes (90 million gigabytes) of data per year – amount so enormous that it has to be stored and processed at numerous locations around the world (via the private cloud). Imagine: you record the movement of every particle moving at the speed of light for the distance of 300 billion kilometres, as well as billions of collisions registered by detectors every second (more about the detectors below).

Fun fact: in order to access all this data, in 1990 CERN scientists (in particular, Tim Berners-Lee) developed the World Wide Web. The current project of decentralized storing and processing of data is named Worldwide LHC Computing Grid (WLCG). Who knows – maybe soon it will find use among a broader audience, just like the WWW once did?

Detectors and collisions

LHC consists of two tubes working at once: in one pipe protons are moving in one direction, in the second tube – in the opposite. And at a few sites around the LHC perimeter they collide. These sites are called experiments, and they’re equipped with detectors of various particles that identify and record data on collisions. Currently there’re 4 collision points and 8 experiments built around them, such as:

– ATLAS (‘A Toroidal Large Hadron Collider Apparatus’) – a super massive particle detector that consists of magnets, pixel detectors, radiation trackers, calorimeters that absorb particles and measure their energy, spectrometers that measure momentum of muons, and other impressive things

– ALICE (‘A Large Ion Collider Experiment’) is used to study ion collisions and explore hot and dense quark-gluon plasma (the primordial form of matter!)

– LHCb (‘Large Hadron Collider beauty’) is dealing with a beauty quark and is targeted at investigating the matter-antimatter symmetry of the Universe

– CMS (‘Compact Muon Solenoid’) is a solenoid magnet designed to measure energy and momentum of photons, electrons, muons and other products of collisions. All to investigate the possibility of extra dimensions and dark matter

Yes, all this hardly-believable stuff is actually researched in a pretty casual way on a real-world site that’s uncomfortably close to the normal flow of life of an ordinary Swiss town. CERN is investigating dark matter and extra dimensions, while you’re working in Power Point or Excel to increase sales of another useless product or service. Is this really what quarks bound into hadrons for 14 billion years ago?

Anyway, detectors used by CERN these days are utilizing cutting-edge technology. However, there’s a long history of other sorts of detectors that were used in the past. For instance, the simplest one is a so-called Cloud Chamber – a particle detector showing ionised trails of cosmic ray particles. Cloud Chambers were then surpassed by Bubble Chambers. One of them, called Gargamelle, was used for discovery of Z and W bosons in 1973. It is now exhibited in the garden of CERN (looking rather retro-futuristic – you can see photos in my Instagram highlights).

Theories and experiments

Theoretical models are designed to explain the world around, and the more consistently they do it, the more explanatory power they have. When the models are also able to forecast things not yet discovered, they’re assumed to have a predictory power. And this is exactly the case of the so-called Standard Model of particle physics. Since its development in the 70s, more and more real-world experiments and discoveries reaffirmed theoretical predictions made by the model. These discoveries include: Higgs boson, tau neutrino, W and Z bosons, and a bunch of other stuff with mysterious names.

The leading cosmological model these days is the Big Bang theory, and its more specific parametrization version is called Lambda-CDM (Cold Dark Matter!). The Big Bang theory is so far supported by two main kinds of evidence. First, the red shift – an empirical observation that the stars are drifting apart – proving that the Universe is expanding (and since it’s expanding exponentially – there must have been a point in time, when all the mass and energy of the Universe was concentrated in just one dot).

The second proof of the Big Bang, the strongest so far, is the existence of the so-called Cosmic Microwave Background (CMB) – or primordial, relic cosmic rays. Remember the funny story about two scientists who detected some electromagnetic radiation, but first thought it’s coming from pigeon feces on the telescope surface? Anyway, the existence of relic radiation is now proven – it’s what remains of the enormous blast of photons released around 14 billion years ago (or more precisely – during the ‘photon decoupling’ epoch). Over time, this energy has been drifting farther and farther apart, its wavelength has been increasing (wavelength is negatively correlated with the amount of energy), so that now it’s manifested only as subtle microwaves with the temperature of 2.7° Kelvin (-268° Celsius, or -450° Fahrenheit). Yes, the space is hostile and cold, its regular temperature is around -270° Celsius.

So searching for more evidence of the Big Bang is a crucial task. Another problem is that the Standard Model of particle physics is currently not reconcilable with the Theory of Relativity. A model that’s able to combine these two (that’s not yet been developed) is supposed to lead to the new grand ‘Theory of Everything’. LHC is at the forefront of experiments that might help to formulate it. And even though the Theory of Everything sounds exciting, trust me, it’s not something you want to dig in – the terms used in that sphere of research feature such words as: Calabi-Yau manifold, Clifford algebras, AdS/CFT correspondence, orthogonal transformations, charge conjugation parity symmetry, and Maldacena duality. In other words, stuff that has surpassed the level of human cognitive capacity a long time ago.

Suppose that the Big Bang theory is proven – what will come next though? Big Freeze, Heat Death? Proton decay, black holes evaporation, positronium decay? Maybe the Big Rip – a hypothetical scenario that claims that since the Universe is expanding, one day distances between particles will become so large that no fundamental forces could hold them together. What will follow next is the desintegration of galaxies and unbounding of star systems, with planets flying away. And then even the space-time itself would be ripped apart.

Another idea is the Big Crunch – theory stating that there could potentially be a never-ending sequence of universes collapsing and expanding. Too bad that all cyclical models of the Universe, although fascinating and optimistic, don’t seem to be scientifically valid – they don’t account for entropy, steadily building up and ultimately leading to the Heat Death. The future is not bright. We’re more likely to freeze to death, and drift away into the spaceless and timeless nothingness, than to experience any sort of eternal recurrence.

Conclusion

CERN is located not far from the Swiss Alps – a mountain range formed over tens of millions of years, as the tectonic plates collided. The process took millions of geological years – compared to this, human life is just a second. But it seems to be an eternity, when the object of your research is an event lasting for one millionth of a second itself. The mere existence of such a sphere as particle physics brings certain optimism.

Not for long though. After visiting CERN, you realize that what you do for life has a 99% chance of being highly irrelevant. What you eat, how many times per week you exercise, what you do as a hobby – all of these are just worthless attributes of a petty life. I previously thought that only art and philosophy (with politics perhaps) can be considered the most noble areas that allow humans to realize their highest human capacities. I was wrong. There’s another sphere: deeper, more fundamental, the sphere that’s underlying everything that social sciences could ever strive to achieve. As Richard Dawkins once wrote:

After sleeping through a hundred million centuries we have finally opened our eyes on a sumptuous planet, sparkling with color, bountiful with life. Within decades we must close our eyes again. Isn’t it a noble, an enlightened way of spending our brief time in the sun, to work at understanding the universe and how we have come to wake up in it? This is how I answer when I am asked—as I am surprisingly often—why I bother to get up in the mornings.

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