Twins in Space

Mark Harris

  • Albert Einstein by Albrecht Fölsing, translated by Ewald Osers
    Viking, 882 pp, £25.00, August 1997, ISBN 0 670 85545 6
  • Einstein: A Life by Denis Brian
    Wiley, 509 pp, £11.99, October 1997, ISBN 0 471 19362 3

Einstein’s life story is almost as well known as his science. He was born in 1879 into a middle-class Jewish family in southern Germany, and went to school in Munich, where he is supposed to have been an unsuccessful pupil and his Greek teacher predicted that he would ‘never amount to anything’. Albrecht Fölsing points out, however, that by 1929 the legend of Einstein’s poor academic record was so widespread that the principal felt obliged to dispel this bad publicity for the school by revealing his (quite respectable) examination marks in a letter to a Munich newspaper. Whatever the case, Einstein did not enjoy his school years, and when his parents moved away from Munich in 1894, escaped without graduating on the grounds that he was medically unfit for further schooling and that, where mathematics was concerned, he was up to graduation level already. After one more year at school in Switzerland he went to the Zurich Polytechnic to study for a diploma in mathematics – there, he was remembered by the teaching staff as a ‘lazy dog’. After receiving his diploma, he applied unsuccessfully for a number of junior academic jobs – within ten years many of the universities that had rejected him would be falling over themselves to hire him as a full professor – and it was only after a long spell of unemployment that he found a job in 1902 in the Bern Patent Office.

His spare time was spent working through the various problems in physics that had interested him as a student, with the aim of getting his name known through publications. The Patent Office, as he later acknowledged, played a key role in his development as a scientist: it forced him to think through problems with precision but also in broad terms, while enabling him to avoid the academic requirement to write superficial papers for journals. In the event, Einstein did produce an impressive number of papers, but they were far from superficial: the four he published in 1905 in Annalen der Physik must rate among the most important scientific publications of the century. Remarkably, he wrote these in near isolation, with few scientific colleagues to bounce his ideas off and only sporadic access to a library.

It’s impossible to talk about the 1905 papers without recourse to an uncomfortable number of superlatives. The first introduced the concept of light ‘quanta’, which challenged the accepted doctrine that light consists of waves of electromagnetic radiation. Ultimately, it was the most revolutionary of all Einstein’s papers, because it led to the development of quantum mechanics, and so to the overturning of Newton’s deterministic universe – a development with which Einstein never felt comfortable. The second paper explained the effect known as Brownian motion, where, for instance, under a microscope, smoke particles are observed to make erratic, jittery movements. Supported as it was by experimental work, Einstein’s theory provided final confirmation that air is composed of molecules, together with a method for determining the number of molecules in a given volume of air. While this may now sound rather quaint, before 1905 the existence of atoms and molecules was not taken for granted. This Brownian motion paper is one of the most frequently cited scientific publications of the 20th century, since the theory has many applications, ranging through physics, chemistry and biology: studies of the way aerosols disperse in the atmosphere are one instance.

The third and fourth papers of 1905 introduced the special theory of relativity. By assuming that the speed of light is constant throughout the universe, Einstein showed that the concepts of time and distance can never be absolute, because the motion of one moving body can only be measured relative to that of another. ‘It used to be thought,’ Einstein explained, ‘that if all things disappeared from the world, space and time would be left. According to relativity theory, however, space and time disappear along with the things.’ In other words, if two identical twins are separated, one staying on Earth, the other travelling the galaxy at speeds close to that of light, the space-bound twin will have aged only a few years on his return, while his brother will be an old man. This runs counter to our everyday understanding of time, but is a simple consequence of the fact that the speed of light has to be a constant for both twins, whatever their relative speeds.

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