The theory: Mass – and why it just disappears

Isaac Newton coined the term in 1687 in his famous tome, Principia Mathematica, and for 200 years scientists were happy to think of mass as simply existing.

Some objects had more mass than others – a brick versus a book, say – and that was that. But scientists now know the world is not so simple. While a brick weighs as much as the atoms inside it, according to the best theory physicists have – one that has passed decades of tests with flying colours – the basic building blocks inside atoms weigh nothing at all. As matter is broken down to ever smaller constituents, from molecules to atoms to quarks, mass appears to evaporate before our eyes.

Higgs came up with an elegant mechanism to solve the problem. It showed that at the very beginning of the universe, the smallest building blocks of nature were truly weightless, but became heavy a fraction of a second later, when the fireball of the big bang cooled. His theory was a breakthrough in itself, but something more profound dropped out of his calculations.

Higgs’s theory showed that mass was produced by a new type of field that clings to particles wherever they are, dragging on them and making the heavy. Some particles find the field more sticky than others. Particles of light are oblivious to it. Others have to wade through it like an elephant in tar. So, in theory, particles can weigh nothing, but as soon as they are in the field, they get heavy.

Detecting the field itself is thought to be impossible with modern technology, but Higgs also predicted a particle that is created in the field, and finding this would be the proof they sought.

Officially, the particle is called the Higgs boson, but its elusive nature and fundamental role led a prominent scientist to rename it the God particle.

• Extract from Massive: The Hunt for the God Particle by Ian Sample