Echo of universe from behind pigeon droppings

Press, 22 September 1977, Page 16

Echo of universe from behind pigeon droppings

By

NIGEL HAWKES

in London

In 1965 an extraordinary paper slipped almost unnoticed into the scientific literature. It was by two radio astronomers, Amo Penzias and Robert Wilson, both Americans, who had used a radio receiver in the shape of a huge horn to eavesdrop on cosmic noises. When they detected a noise a hundred times louder than they expected, they hardly knew whether to believe it or not.

As it happened, a family of pigeons had been nesting in the horn, built at Bell Telephone Laboratories in New Jersey for experiments with one of the early communications satellites "Echo.” The pigeons had deposited what Penzias delicately described as "a white dielectric material” all over the in«ide of the horn The two scientists were afraid that they might be listening not to the music of the spheres, but to simple static caused by pigeon droppings.

But even after careful cleaning and eliminating all possible sources of interference. the signals were still there. Wherever Penzias and Wilson pointed the horn, there was the noise, like a universal background hum. It came from nowhere, yet was everywhere. What they had discovered, without realising it, was the dying echo of the huge explosion with which the universe had begun.

This finding, once its full significance had been realised, made it possible to discuss in considerable detail how exartlv the universe had begun. Or rather, not nrecicelv how it began, since the first one hundredth of a enrond after the big bang still remains bevond the imagination of eve” th® most brazen of theoretical phvsictsts. Put th® neriod a'to- th® first on® himdredth of a second up to, sav, 700.000 years, when the formation of stars began, can now b® discussed in a sensible fashion

This has now’ been done by p-nf®ssor Steven Weinbere of Harvard in a book called ••Thp First Three Minutes” fnuhiished bv Andre Deutsch. London). Tt is a fantastic storv. peonled by exotic particles like the neutrino (which has no ma«s. no eieetric charge, and can pas® right through the Earth with no trouble at all) and set in a period when the far-fetched

physics of the particle accelerators was the norm, and conventional physics and chemistry were no more than a theoretical abstraction. Professor Weinberg, who is himself a specialist in particle physics, has written with the intelligent general reader in mind. He pictures his reader, he says, as “a smart old attorney who does not speak my language, but who expects none the less to hear some convincing arguments before he makes up his mind.” The book has been received enthusiastically by reviewers, and could be about to turn Professor Weinberg into something of a celebrity, a fate he fears. The universe began, according to the now accepted model which Weinberg takes as his starting point, with a dense soup of elementary particles at a temperative of 100.000 million degrees, much hotter than the centre of even the hottest star. The universe was filled with light, or at least with photons, the elementary particles of which light consists. New particles were continuously being created out of energy, and then being annihilated again. As the universe cooled the particles began to combine together into atomic nuclei, then into complete atoms. Within half-an-hour of the big bang, most of the interesting physics was over; but it was another 700,000 years before chemistry began, with the formation of stable atoms and the clumping together of matter to form galaxies and stars. If the universe began with a bang — as now seems agreed — will it go on expanding for ever? Or will it, like a ball thrown into the air, eventually begin to fall back again until it again forms the dense soup of elementary particles with which it began? There is no answer yet to this Question, although Professor Weinberg believes that it will probably go on expanding for ever. Against this background, the foie of man seems almost incidental. It is hard to believe. as Professor Weinberg himself admits, that human life is no more than the consecuence of a chain of accidents reaching back to the first three minutes of the universe, but that is what science teaches. “The more the universe seems comprehensible. the more it also seems pointless,’* he concludes.

Professor Weinberg, who is in his forties, admits to one habit unusual among physicists. He works best with the television on. “The programmes should not be too interesting though, or I will get too interested. I think my ideal would be films I had seen before — say Casablanca all the time.” 0.F.N.5., Copyright.