Cern special: The 9 billion dollar question

Today, mankind’s greatest experiment begins as the Large Hadron Collider powers up. The cost is huge, the scale is massive – and the discoveries could be enormous. But, asks Andy McSmith, what does it all add up to?

It was Oscar Wilde who declared that "all art is useless" – which was not a condemnation, but a proclamation. If you want to create something of beauty, he meant, do not be distracted by people who ask what it is for. On that basis, whatever emerges from the £4.4bn experiment that begins today in the vast complex built at the Cern – The European Organisation for Nuclear Research – laboratory near Geneva, where infinitesimally small particles travelling at mind-boggling speeds will crash together with so much force that they almost replicate the Big Bang, could be called the most expensive work of art in human history.

Mathematicians and physicists have a sense of the aesthetic, as surely as poets and dramatists. In Einstein's theory of relativity or Kepler's laws of planetary motion, they see works of great simplicity and beauty. What they long for now is a simple and beautiful "theory of everything" that will explain the whole of physics, from the movement of galaxies to the behaviour of subatomic particles, because there is a hole in theoretical physics which causes more distress to the 6,500 scientists working on Cern's Large Hadron Collider (LHC) than the scary speculation about the black hole that some people think will swallow up earth if their experiment goes wrong.

At present, anything big enough for us to see, from a star to a speck of dust, is known to obey one set of physical laws, but at the subatomic level, among those unimaginably tiny particles that are the building blocks of the universe, another set of laws apply. No one has definitively reconciled the two.

Cern scientists make final preparations

Moreover, the best explanation the human race has so far devised for explaining the behaviour of subatomic particles, the so-called Standard Model, is not a work of art, it is a monstrosity. Whereas Einstein's equation relating mass to energy is expressed in just characters, E=mc2, writing out the Standard Model goes on for page after ugly page of symbols.

And even then, it leaves an awkward gap. Put it this way: if you walked beneath the window of a school classroom, and a pupil dropped a feather on your head, you would not mind; but if he dropped a brick, that would hurt, because a brick is heavy and a feather is light. But not according to the Standard Model, because nowhere in the theory is there any indication that particles have mass. Down there among the subatomic particles, all is seemingly weightless. That is very annoying for those great artists who poke at the boundaries of theoretical physics. They want to know why, in the trillionth of a second after it all began with the Big Bang, stuff came into existence where there had been no stuff before. One answer, worked out in theory, assumes the existence of something called the Higgs boson, or more fancifully, the God particle.

To you or me, Higgs boson – if it exists – is so unimaginably tiny that it is no surprise no instrument has found it; but in the subatomic world, it is a monster, a particle so much vaster than all those quarks, Z bosons and other subatomic oddities that it can only exist for an immeasurable fraction of a second before it disintegrates.

Even the LHC will not catch a Higgs boson, if it exists. What the physicists expect, however, is that the machinery will pick up proof that a Higgs boson was there for a fraction of a microsecond, from the debris left behind from its disintegration.

If that happens, science has taken a giant leap forward. We will know something that previously we only supposed. Conversely, if the vast experiment at Cern does not produce a Higgs boson, the theoretical physicists will have to retrace their steps and think a whole new explanation for life, the universe and everything. But cosmologists – who study the biggest things in the universe – are hoping that the unprecedented experiment in Geneva will uncover "supersymmetric particles", because if they exist, they turn the key to one of the great mysteries of outer space – why are galaxies 10 times heavier that they appear to be?

There are two ways of estimating the total mass of a galaxy. You can either study what you can see, and deduce its total mass, or you can study the movement of the stars on the outermost edge of the galaxy, and calculate the gravitational pull. It has been done many times, and each time one of the two methods is used it produces a different result from the other. The discrepancies have been so consistent that the only satisfactory answer is that there is a vast amount of matter in the universe that has mass, but which cannot be seen or detected.

In truth we cannot know what the experiment will throw up. When the particles start to collide in the LHC in October, they will generate an energy that will be like concentrating the energy from a head on collision between two high-speed electric trains into a pinpoint. The theory that the world will vanish in a black hole is only one of the fanciful suppositions about what will happen next. Another is that time travellers will use the wormhole in the space-time continuum generated in the LHC to pay us a visit. Professor Keith Mason, chief executive of the Science and Technology Facilities Council said: "I believe we are poised on the threshold of a new age of physics. Scientists waiting for the LHC dare to ask the biggest questions that exist in modern science. They want to test our understanding of the universe and find out if dark matter exists, whether the four dimensions of space-time are it or in fact there are eleven dimensions! They want to know why some particles have mass and some, like particles of light, don't.

"Using the four detectors... we will be able to look at these mysteries that go to the fundamental nature of the universe."

To the question "what is the use of it all?", the short answer is that it is "useless – but not for long". "No one knows exactly what new fields of knowledge the LHC will open up to us," says Dr Robert Kirby-Harris, chief executive of the Institute of Physics. But he forecasts that; "the technological payback will be huge. The need to deal with the vast quantities of data the LHC will produce has already resulted in new grid technology to increase storage and capacity, and improve the capacity of the internet to carry more and more data. And I have no doubt that this will encourage more school students to study physics – exactly what the UK needs to ensure a vibrant future."

And anyone who objects to having nearly £5bn of European taxpayers' money spent on a plaything for boffins should consider this: years ago, the scientists at Cern wanted to improve the means by which they communicated by computer with other scientists around the world, so they designed the World Wide Web. Then they gave the technology away, for nothing. Consider how much money has been made from that free gift... and stop complaining.