Coloured scanning electron micrograph (SEM) of connecting wires on a silicon computer chip (Image: Eye of Science/SPL)

IN 1965, a year before the first pocket calculator was invented, a young physicist from Silicon Valley, Gordon Moore, made a daring prediction. He claimed that the number of components squeezed onto a single silicon chip would double about every two years. And double, and double and continue to double. If he had been right, the best silicon chips today would contain an unbelievable 100 million single components.

The true figure is more like 2 billion: Moore had underestimated how fast the shrinking trend would take off. Since the mid-1970s, though, his “law” has been a bankable certainty, influencing economic, social and scientific developments in ways that are hard to overstate. Google, genome sequencing, multiplayer video games, the search for the “God particle”: all rely on silicon’s seemingly limitless ability to deliver more computing speed and capacity – for an ever-diminishing price.

Moore’s law means that the cellphone or iPod in your pocket today has more byte-crunching power than the mainframes on the Apollo spacecraft, at the planning stage when the prediction was made. Had aviation followed a similar trajectory, a flight from New York to Paris in 2005 would have cost a cent and lasted less than a second, Intel – the chip giant Moore co-founded in 1968 – calculated.

Can the trend go on? Reports of the imminent death of Moore’s law have been around almost as long as the law itself, and have always proved exaggerated. But now there is concrete cause for concern. The smallest features on today’s state-of-the-art chips are just …