Light years ahead

Did Albert Einstein invent the 20th century? asks Arthur Miller.

How Albert Einstein became an icon of the 20th century is a fabulous story.

In the magic year 1905, he was a middle-class, middle-level civil servant - a patent clerk, toiling six days a week, eight hours a day, in Berne, Switzerland, an intellectual backwater. His student career had been such a disaster that it took the influence of a friend's father to obtain the position.

Amid severe problems of earthly existence, Einstein's mind soared into the cosmos. For 10 years, since he was 15, he had been preoccupied with what he considered to be a glaring deficiency in physics. According to the way the theory of light was formulated, the speed of light should depend on the motion of its source - being faster or slower depending on whether the source is moving towards or away from the observer. But this was at odds with the expected behaviour of light and with actual experimental results that gave no change.

While at his desk in the patent office Einstein had a brainstorm. Let's assume, he reasoned, that the speed of light actually was independent of the motion of its source. Since scientists used light signals to synchronise clocks, this assumption meant that time was relative. Your time is the same as mine only if we are not moving relative to each other. This is the basis of Einstein's 1905 relativity theory.

Einstein's thoughts in those years included how the newly discovered quantum theory bore on the structure of light and atoms. In 1905 everything gelled and he wrote up his results in four papers that changed the course of science and of history.

In the first, he explored the nature of light by proposing that light could be particles, light quanta. The second suggested ways to prove that atoms actually existed. The third was the relativity paper and the fourth contained a result that Einstein had overlooked - the equivalence of mass and energy: e=mc2.

Forty years later on August 6, 1945 at Hiroshima, this equation entered the vocabulary of the 20th century and beyond. Certain results of these papers affect our daily lives. Light quanta were essential for inventing doors that open automatically. Results from his second paper are useful for assessing the motion of sand particles in cement mixes. Relativity is indispensable for the accuracy of the GPS (Global Positioning System), owing to corrections in time due to the motion of orbiting satellites.

At first, Einstein's discoveries of 1905 were either ignored or appreciated for all the wrong reasons and he remained in the patent office for four more years. Nevertheless, his Berne period, 1902-1909, was his most creative.

Einstein's great passion after 1905 was expanding his relativity theory to include gravity. The finished product appeared a decade later as the general theory of relativity. It made breathtaking predictions such as the deflection of starlight in the vicinity of massive objects, like the Sun.

This was verified in 1919 by the English astrophysicist Arthur Stanley Eddington. What touched everyone was that, in a war-weary world, a theory formulated by a German scientist had been proven by an Englishman. There emerged the image of someone who had divined the laws of the cosmos, who even looked as if he had witnessed the creation itself. Einstein became an icon.

And then there is general relativity's most profound prediction: massive stars at the end of their lives can collapse to a minuscule object of such immense density that space and time will engulf it like a shroud from which nothing can escape, not even light. It will fall into a black hole.

The Year of Science, 2005, celebrates the power of human imagination. It also celebrates one man's fortitude to succeed amid circumstances that would have deterred most others. Such stories inspire us all.

Arthur I Miller is professor of history and philosophy of science at University College London. His book, Empire of the Stars: Obsession, Friendship and Betrayal in the Quest for Black Holes, will be published by Little Brown, March 3

Einstein's ground-breaking papers on special relativity, the photoelectric effect and Brownian motion were published in 1905. One hundred years later, the UK and Ireland are celebrating Einstein Year as their contribution to the World Year of Physics. Hundreds of events will take place including a special programme for ages 11-14, including a celebration of Einstein's birthday, March 14; a Lab in a Lorry tour; a Rambert Dance Company production inspired by Einstein and physics; and touring hands-on exhibitions. Institute of Physics, tel: 020 7470 4800;;

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