Large Hadron Collider – a lay person’s explanatory view

Why the LHC does not pose a significant risk to the human race.

Ok so, as an interested amateur scientist, I’ve waited a good proportion of my life for this experiment to start. It is, perhaps, one of the greatest experiments carried out by mankind and may bring amazing insights in to the structure of everything, ourselves included.

Yet many seem to fear that the end of the world is nigh. I have found the scare mongering of the press & the resulting ignorant comments of those who know no better to be rather frustrating. Thus I shall attempt to explain, in layman’s language & without much maths, just how preposterous all these suggestions of doom are.

Please forgive me if I miss the odd zero or clarify things insufficiently but I’m not a professional mathematician or physicist, just an interested amateur who doesn’t wish to see lay people scared by an experiment that they could instead be fascinated by. After all it may answer some of the questions that mankind has pondered for thousands of years.

The fear appears to be that a black hole could be born within the Collider and that this would then rapidly expand to consume the earth – here is why this is not the case.

1. What is the LHC?

It is the largest particle accelerator produced by humans. Simply put, it is a long underground railway like tunnel through which 2 pulses of particles will travel & then collide. Particle accelerators have been used by physicists for many years, safely.

In fact there are 2 tubes surrounded by very powerful magnets that first acquire & focus then accelerate a packet of atomic particles. The packet is about 1 metre long and can be accelerated to almost the speed of light. At certain points these 2 packet streams can be made to crossover within a detector. When a collision occurs between atomic particles in the packets, then the detector can record an image of what happens.

2. Can it create black holes?

Probably not, but yes it may just about be feasible for a miniscule black hole to form but you need to understand a bit more about black holes …

a] Astronomers can calculate the relationship between the mass of a black hole and its size, or most importantly the size of its event horizon (the place where things get sucked in). A black hole with the mass of our entire solar system would only be several kilometres across.

b] Black holes can & do lose energy via ‘evaporation’ – this is called Hawking radiation as proposed by Stephen Hawking.

Read on to see why these are important facts…

3. So why isn’t this tiny black hole dangerous?

Briefly, due to its tiny size & the losses by Hawking radiation, it will cease to exist almost the moment it is created.

More detail :

According to Einstein’s most famous equation E=mc2, energy may be converted to matter & vice versa; it is this fact that the LHC relies upon for its experiments to work. At maximum energy, the LHC can accelerate 2 lead ions in to each other at almost the speed of light. Following the proven laws of physics the maximum mass it can create in such a collision is about 2e-21 kg, that’s 21 decimal places if you’re not in to scientific notation. It’s not much is it! If we use the known ratio of size to mass for black holes then its size will be in the order of 10-49 metres or 0.000000000000… no I’m not going to type 49 zeroes! You get the gist, this is one very small thing, many many times smaller than an atom. So in but an instance pff! and it’s gone. Nothing, zip, nada – it wouldn’t harm a flea – its gone, evaporated, is no more.

4. So what if the journalists know more than Stephen Hawking? What if it didn’t evaporate? What could this 0.0000000000000000000000000000000000000000000000001 of a metre black hole do?

Not much really, you see its just so small, a proton is about 1033 times bigger. It can hang around between atoms & sub atomic particles, do nothing, for millennia. It might take a million years before an atom fell within its event horizon. Even then so it swallows one atom, hardly a disaster. It’s many times denser than an atom so it won’t increase its mass or size much by swallowing one atom. So another million years go by and then it swallows a second atom – this is going to make watching paint dry, a fascinating sport. We are going to be long gone before this black hole can cause anything even noticeable. Our sun will long since have run out of energy, maybe our galaxy will have merged with Andromeda before this little black hole grows up!

In summary, it’s unlikely that the LHC will create a black hole, even if it does then it would evaporate in the merest instance of time. If the physicists were completely wrong and it didn’t evaporate, it still wouldn’t be an issue within any timescale that could possibly effect humans – there are much bigger problems for the world.

Part 2 Why do the LHC experiments?

There are many reasons but here are some of the ones that are personally important to me:

· To ask deep questions of our curiosity is one of the noblest traits of humans – to not do so would be a failure of humanity.

· Pure research usually spawns the most useful & positive advances, but we don’t know what they’ll be until many years after the research.

· The unification of gravity in to a theory of everything will bring a huge step forward in understanding.

· For this we need to confirm the existence or not of the Higgs field and its related boson.

· We also need an indication on extra dimensionality & M-theory (strings).

· If humans are going to survive the mess that they make on this planet then it’s likely that we’ll need to move on. Perhaps it’d be a good idea to understand more of what’s out there before we travel.

· Consequently we need to probe dark matter & dark energy; it’s probably over 90% of what’s out there.

· Too many people accept things “just because”, religion’s explanations would be a grand example; this causes untold problems and disasters. A truly thinking person asks for experimental evidence – the LHC is part of providing that.

I hope that you can find interest & enjoyment in the discoveries that will come over the next few years.


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  • Tuguldur

    September 16, 2008 at 4:17 am Reply

    you’re right anna. But many other scientists believe the current setup of LHC won’t yield any useful experimental data. Even Hawking put 100$ on bet for this point.

  • antamuk

    September 16, 2008 at 10:57 am Reply

    Hi Tuguldur

    Good to hear from you.

    As I understand it Hawking’s bet was that they won’t find the Higgs Boson, which in itself would be a useful result. It’s a win win situation on the Higgs. Anyway Hawking works that way remember his bet with Kip Thorne envolving a certain top shelf magazine 🙂

    On other topics he expects great breakthroughs from the LHC, as do most particle physicists. The surprises will be the best ones; though it may take some time to get them.

    Clear Skies to you.

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