Thursday, 12 July 2012

The incomprehensible Higgs!

For the last week, friends have been asking me about the seemingly incomprehensible Higgs revelation and what it means.  I've tried to admit to them that I really don't know enough to contemplate understanding the issues involved.  I have asked colleagues at work who are much better physicists than I ever aspire to be.  "What do you make of all this Higgs business?"  Most of them are in the same state as me, and feeling equally guilty about it.  Most agree that the scientists at CERN have been unusually unsuccessful at explaining why so much money has been spent on their project.

As it happens, I don't think £10 billion is a lot of money (on the grand scheme of things, compared with banks, oil rigs and the 'Nolymics') and I don't think it has been spent unwisely either.  So - I'll have a go at explaining the topic of the Higgs with my usual kitchen analogies.  They work very well when trying to explain fusion to non-technical people.  Wish me luck!  Its not that I'm superstitious, you understand!  It is just outside my normal area of experience to try to explain this topic.  Depending on how this goes, I might update it to incorporate other helpful analogies and metaphors that you, my dear readers, might provide.

Initially I'm going to cheat and plagiarise a little(Perhaps I should say 'quote' rather than 'plagiarise'?)  In 1993, the UK Science Minister, William Waldegrave, issued a challenge to physicists to answer the question 'What is the Higgs boson, and why do we want to find it?' on one side of a single sheet of paper. The winning entry starts like this . . .

"Imagine a cocktail party of political party workers who are uniformly distributed across the floor, all talking to their nearest neighbours. The ex-Prime Minister enters and crosses the room. All of the workers in her neighbourhood are strongly attracted to her and cluster round her. As she moves she attracts the people she comes close to, while the ones she has left return to their even spacing. Because of the knot of people always clustered around her she acquires a greater mass than normal, that is she has more momentum for the same speed of movement across the room. Once moving she is hard to stop, and once stopped she is harder to get moving again because the clustering process has to be restarted."

I think I need to take one step back.  What is mass?  Non-scientists find this difficult.  In terms of kitchen physics, mass is weight.**  In the analogy above, you can see that Mrs Thatcher effectively gains weight from the cluster of people around her.  Being 'heavier' it is harder to get her moving again if she stops, just as a wheel barrow full of gravel is harder to move than an empty barrow.  (Sorry for moving from the kitchen to the garden!)

Those clustering people do not represent the Higgs boson - the so-called 'God particle'.  We'll come to that later.  They represent something called the 'Higgs field'.  Now I need to explain what a field is.  In kitchen terms I can do that by asking what happens when you drop something.  It falls to the floor because of the Earth's gravitational field.  It is something intangible but undeniable.  Stop believing in this field at your peril.  Without the gravitational field that attracts you to the Earth you would float off into space.  If you ignore it you'll be surprised when you fall and hurt yourself.  The force of gravity comes from the interaction of mass with the gravitational field.  (Sorry - I have to use the word mass here instead of weight, but if you don't know the difference please ignore that.)

Since this is a difficult concept and I promised kitchen physics, cast your mind to fridge magnets.  Magnetism is the result of another field.  Magnets attract or repel each other because of a magnetic field.  No particles are involved.  The North pole of a magnet attracts South poles (and fridges) but repels other North poles.  We have all played with magnets and been amazed by the powerful effects of a magnetic field.  So without realising it, we intuitively know what a field feels like.

A few decades ago, Peter Higgs and a few others realised that mass (or 'weight') could actually be explained if there was another kind of field in the universe.  This field has been called the 'Higgs Field'.  Nobody knew whether it existed or not.  It was just a really good explanation of the observable facts.  The big question was whether it could be shown to exist.

The way that this can be demonstrated is by looking for a particle that is associated with the Higgs field.

Tomorrow - Why is the 'God particle' relevant to me?  I'll try to explain where the Higgs particle comes into the picture.

Meanwhile perhaps someone can tell me what this has to do with God?  The biggest mystery to me is the source and rationale for the ridiculous name "The God Particle".

**Actually, strictly speaking, what we think of as a weight of 1kg is really the force that the earth's gravitational field exerts on a mass of 1kg.  But that's just scientific pedantry to show to other semi-scientists like me that I know!

1 comment:

Rosa Rubicondior said...

'God Particle': That term is attributed to Richard Lederman from the title of his 1993 book "The God Particle: If the Universe Is the Answer, What Is the Question?". However, this may have been at the insistence of his publishers, Dell Publishing, who objected to his original title "The Goddamn Particle".