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Big bangs and black holes

Between the borders of Switzerland and France you’ll find a hole that’s as deep as the length of one and a half football fields. If you think that’s deep, it would also take you about a day to walk all the way around this hole’s edge!

So, what’s so special about this big hole in the ground? Taking 12 years to build and at a cost of £5 billion, it’s the most expensive man-made hole ever built. Inside it you’ll find the biggest machine in the world running the biggest experiment in history. Not impressed yet? OK, how about this: over 10,000 scientists and engineers from over 100 countries, not to mention hundreds of universities and laboratories, thought that this experiment was so important they got together to make sure it happened.

The 27km tube at CERN

What’s in the hole?

The hole looks like a circular tube. It measures 27km around its circumference (like a huge circular tube as long as 17 miles) and it lies 100m below the surface. When it’s running it will contain the hottest, coldest and emptiest spots in the Galaxy.

How does it work?

Over 10,000 tonnes of liquid nitrogen and helium will keep its superconducting magnets at a chilly -271.3°C (-456.34°F). The tube inside the magnets is so empty it contains fewer molecules per cubic metre than interstellar space. Inside will be a tiny region that is heated to well over 1,000,000,000,000,000°C (1800000000000032°F), that’s hotter than the middle of the hottest stars.

ATLAS Detector

Why bother?

OK, enough of believe it or not and facts and figures, why bother? To answer that one we need a little lesson in physics. DON’T PANIC! The physics is reasonably easy to understand. The big machine is of course a particle accelerator. Sounds flash and complicated doesn’t it? In the detail it is, but what it does is very simple.

It takes small pieces of matter and accelerates them to huge speeds. You could use any machine you liked as long as it could get some ‘stuff’ up to a speed of about 99.99 per cent of the speed of light. By far the easiest way of accelerating stuff is to pick a charged particle and use electric fields to move it. Magnets can then be used to steer it. So make a big ring of magnets to keep pushing the charged particle around corners and a high voltage to push or pull it along. With enough volts very high speeds can be achieved.

The Large Hadron Collider (LHC) uses about 7,000,000,000,000 volts. In fact it requires rather a lot of power to run the big ring. It will only operate regularly during the summer months because the Swiss national grid doesn’t have enough juice to spare in the winter.

Inside the LHC

So we have a bit of stuff going very fast, what can you do with it?

Remember anything moving has energy, Kinetic energy to be precise. Now here comes the equation,
E = MC2. This is the most famous equation in the whole of science, and for very good reason.

All it says is energy and matter are just two ways of looking at the same thing. Matter is just energy in its frozen state. Because C2 (the speed of light squared – 9 x 1016) is such a big number a small amount of matter is made from a lot of energy. You can unfreeze some of that matter and turn it back into energy using an atomic bomb. What the big ring does is the same trick, but backwards. It takes kinetic energy and freezes it back into matter. The problem is you need an awful lot of energy crammed into a very small space.

Calorimeter and Muon Chamber in the LHC

To do this you use two beams of charged particles moving in opposite directions. When they collide the energy density is truly awesome, and some of this energy freezes into matter. It becomes many and more massive particles than those that entered the collision. This is what happened during the big bang. A huge amount of energy was crammed into a very small space, less than the size of an atom. As this primordial atom expanded and cooled all the particles that make up the universe around us were frozen out of the energy.

This is why physicists keep building bigger and more powerful particle accelerators, to cram more and more energy into smaller and smaller spaces. It is then possible to get closer to what conditions were like in the big bang. This in turn means we can make more massive and exotic particles.

LHC Magnets

A slightly alternative view or what it’s really all about

The above explanation is fine and is probably pretty close to what your physics teacher has told you. It still doesn’t quite grasp how profound the experiment really is. What the experiment is actually looking at is the vacuum in the tube and how it behaves. We are really looking at the nature of nothing at all, complete emptiness. What is it and how does it know to how produce matter when you give it a jolt with a lot of energy?

It must have some kind of a ‘plan’ built into it so it ‘knows’ how to do this. Einstein said that his work had been a quest to know the mind of God. This is getting as close to those thoughts as anyone has ever achieved, if you believe in God! Now there’s another interesting question……


Build a functioning particle accelerator out of an old washing machine, three carrier bags and ten metres of string. The first person to discover the Higgs boson wins a Nobel prize and week in Disneyland.

Any alternative universes created must not contain, homework, cellulite or warm beer. Any person creating a world consuming black hole will be immediately disqualified and then crushed out of existence.

The big questions:

Can it be justified to spend £5 billion on the answer to perhaps the biggest question ever asked?

What is a black hole?

Could there be other ways of explaining the gravitational effects of dark matter?

What is the multiverse?