According to Hoyle

Cosmology, the study of the universe as a whole, is science's fairytale princess --grimly guarded by all manner of intellectual spears, deadfalls and barriers. Even the scientists' imperfect understanding of the strange, violent and orderly ways of the stars and the galaxies requires a mastery of nearly every known technique of physics and mathematics. To assail the defenses of cosmology requires versatile, brash and preferably young men.

In 1937 two such brash young men at England's Cambridge University set out for an assault on cosmology's castle. Fred Hoyle, 22, and Raymond Arthur Lyttleton, 25, of St. John's College, earned their livings (as they still do) by teaching mathematics to Cambridge undergraduates. After hours they planned their campaigns to explain the universe--not just the stars and the galaxies, but the whole vast mechanism, compounded of space and time, of mass and energy, which produces the "objects" seen by telescopes, as well as that oddity, the earth, and its curious inhabitant, man.

Last week an extraordinary theory of the universe, developed chiefly by the Hoyle & Lyttleton team, ranked as a leading conversation piece in British intellectual circles. It was more than that; broadcast by radio, spread by a bestselling book,* debated in learned societies, it was bidding for a place among Britain's most striking contributions to modern scientific philosophy. It was, of course, also being attacked. Nothing so daring had appeared in the field of cosmology since the early '30s, when Sir James Jeans and Sir Arthur Stanley Eddington led man's imagination out among the "island universes" in the depths of space.

Opening for Theory. When Hoyle & Lyttleton began their collaboration, the time seemed propitious for a "new cosmology." Observational astronomy had long since moved away from Cambridge; as a hunting ground for giant telescopes', the grey English sky cannot compete with the sparkling sky of California. But learned little papers from U.S. observatories, bristling with the difficult figures dear to cosmologists, kept crossing the Atlantic.

m An enormous amount had been learned since the days of Eddington and Jeans. The chemical composition of stars was known: they are mostly hydrogen. The source of their energy was known: it is chiefly a nuclear reaction that turns hydrogen into helium. The stars--at least those within the telescope's field--had been measured, studied, divided into classes. The galaxies, those vast swirls of stars out in distant space, had also been measured and classified. There were new theories too, and good ones, but no general theory to knit things together. This was because (as Hoyle explains disarmingly) there was no one with enough knowledge imagination and daring to do the formidable job.

Interstellar Stuff. Even before they first met, Hoyle and Lyttleton had spotted independently what they both considered a key bit of new information: that the major part of the matter in the universe is not in the stars but in the thin stuff between them. On a clear night a man can see, even with the naked eye clouds of "interstellar matter." They look like black holes punched in the Milky Way. With a telescope the astronomer can see long dark filaments and great round blobs, some so huge that it takes light 100 years (at 186,000 miles per second) to flash across their diameters. Made chiefly of hydrogen, mixed in places with dust of heavier elements, they are thinner than the finest laboratory "vacuum " but they outweigh all the stars scattered through and among them.

Many astronomers had agreed that the stars are probably condensations formed from interstellar gas. Hoyle and Lyttleton went further: they concluded, after long mathematical labor, that a star's "fate" (what happens to it during its life of many billions of years) is determined by how much interstellar gas and dust it has managed to gather. It may capture only a small amount, and so remain a commonplace star, like the sun. It may capture a lot, become unstable and eventually blow up.

Under the Desk. About the time Hoyle and Lyttleton reached this point of their reasoning, World War II put cosmology i ice. Both young mathematicians went into war work--Lyttleton into the War Office in London as a technical adviser and Hoyle into radar development All through the blitz and the buzz-bombs Lyttleton kept publishing small, abstruse papers. Hoyle, by his own account, worked on cosmology "under the desk" like a schoolboy reading comics instead of doing his arithmetic.

After the war both went back to Cambridge. There they found two kindred souls, Hermann Bondi and Thomas Gold Trinity College, also mathematicians, who had approached the problem of the universe from a more philosophical angle and were reaching similar conclusions. In eager discussions that sometimes developed into mathematical brawls, the four men began to hammer out their theories.

Genesis of Galaxies. The Hoyle-Lyttleton-Bondi-Gold universe has no beginning and no end, no middle and no circumference in either time or space It is hard to start describing such an endless, begmnmgless object. One way is to imagine all of space filled uniformly with very thin hydrogen, simplest and lightest of the elements. Such a uniform gas is gravitationally unstable." Its atoms attract one another and gradually form into clouds, rather as a film of water on glass gathers into drops. The clouds, cruising through space for billions of years eventually crowd together in enormous gaseous masses that weigh as much as billions of great stars.

This mass of hydrogen, a nascent galaxy, spins as it forms, and centrifugal force spreads it into a wheel-like disk ten lightyears* thick and 60,000 light-years in diameter. At this early stage the whole mass is dark, as in the Biblical account of the first day of Creation,/- but "gravitational instability" is still on the job. Gas clots form, pack denser and denser; they also grow hot as gravitational energy (the energy of matter falling toward a center) turns into heat. When a gas cloud has contracted to something like one-millionth of its original diameter, its center gets hot enough to start the nuclear reaction which turns hydrogen into helium with a great release of energy.

Such a glowing, reacting mass is an ordinary star--like the sun. But it does not contract indefinitely. As soon as the energy generated within it balances the radiation escaping from its surface, the star becomes stable. If left to itself it could continue for many billions of years, slowly "burning" its hydrogen.

Growth of Stars. Most stars are not left to themselves, at least not all the time. A good part of the gas that forms the young galaxy remains as thin gas. Both stars and gas move in swirls like the eddies and surges in flowing water, and these motions frequently carry the stars through the clouds of gas.

What happens then was worked out chiefly by Lyttleton. The easiest way to understand it is to imagine a moving gas cloud passing a stationary star. As the individual particles in the cloud come under the influence of the star's gravitation, they are pulled into curving paths that lead to a line of points directly behind the star (see diagram). There they collide with one another, and their energy of motion is turned into heat. Robbed in this way of the speed which might have carried them safely past the star, many of them are captured by it, falling into it in a mighty stream.

Cloud Tunnels. How many particles are captured can be calculated mathematically. It depends on their speed. If the particles are passing the star at as much as 30,000 miles an hour, few are captured. Their curves are rather flat; they collide far away from the star and rarely fall into it. But if the speed is low (around 5,000 miles an hour), the particles curve sharply, collide close to the star and fall into it in great numbers. Behind the star an empty "tunnel" is left in the ravaged dust cloud. The tunnel is fat if the speed is low, thin if it is high.

At present, says Hoyle, the sun is not catching much material; it is moving too fast through too thin a cloud. Some time in the past, however, it must have tunneled a dense cloud. One proof of this hypothesis is the sun's spectacular bevy of comets. These "bagsful of nothing" (probably loose aggregations of small particles and gas) plunge toward the sun on long, elliptical orbits. They whip around the sun and streak out again into cold, dark space. They are mementos, says Lyttleton, of a time when the sun and its brood of planets were passing through a dense cloud of interstellar matter. Loose blobs of captured material falling toward the sun were deflected by the pull of the larger planets. Once having missed the sun, they were condemned by the laws of celestial mechanics to swing wearily around it.

Spendthrift Stars. The sun's period of tunneling must have been smalltime stuff, for the sun has remained an average, ordinary, well-adjusted star. This is probably just as well for the sun's tender planets. When a star gathers too much interstellar material, a spectacular fate awaits it. Its great mass forces it to burn up its hydrogen at an abnormal rate. It shines with a steel-blue light, perhaps 1,000 times more brilliant than the sun. Such spendthrift stars are called "supergiants." Like overly ambitious men who burn themselves out, they come to an early end. The hydrogen in a supergiant is consumed, says Hoyle, in some 500 million years, while a prudent star, e.g., the sun, makes its smaller portion last 50 billion years.

What happens when the hydrogen of the spendthrift star has all turned into helium? With no more energy being generated in its interior, says Hoyle, the great star begins to contract. Its matter, falling toward the center, makes the interior hotter & hotter. Simultaneously the whole mass, which has been revolving slowly as most stars do, begins to spin faster as it shrinks, just as a skater spins faster when he reduces his "effective diameter" by letting his outstretched arms fall to his sides. Eventually the star is spinning so fast that portions of it may fly off into space, exposing briefly the hot interior and causing one of those stellar flare-ups that astronomers call a "nova."

Sometimes the spinning, contracting star does not sputter its matter away. Sometimes it goes on contracting, spinning faster & faster, getting hotter & hotter. Calculations show, says Hoyle, that in its last days such a star must be a fearsome object indeed. It is smaller than the earth, but a cubic inch of material from near its center weighs about a billion tons. Its surface, emitting a blast of X rays, revolves at 100 million m.p.h.

When the temperature of the doomed star's interior approaches some 300 times that of the interior of the sun, vast numbers of free neutrons come suddenly into being. Nuclear reactions take place which form heavy elements (iron, uranium) out of the predominant helium. Such reactions absorb energy and so reduce suddenly the temperature of the star's interior. This is the end. The star collapses, releasing so much gravitational energy in a matter of minutes that much of its substance is blown away in a stupendous explosion. The outer layers fly off as incandescent gas, at millions of miles per hour. For a few days the detonating star shines brighter than all the ten billion stars in the galaxy put together. Soon the great flash dies down. All that remains of the spendthrift star is a faint "white dwarf"--its XA'/I Se' burned-out nucleus.

Where Planets Come From. Such a monster detonation is called a supernova.

Astronomers believe that in the "local " or Milky Way galaxy of ten billion-odd stars a supernova blows up each two or three nundred years.

Hoyle is particularly interested in supernovae because he and Lyttleton believe that they are the source of planetary systems including the earth's. There are several features of the solar system that seem to fat the Hoyle-Lyttleton theory The planets, for instance, are made mostly of heavy elements, while the sun is made mostly of hydrogen and helium. Another fact is that the planets are revolving rapidly a long way from the slowly turning sun, which makes it unlikely that they were ever a part of it. Hoyle and Lyttleton believe that they never were. The planets, they say, came from a supernova.

About half the stars within man's sight hey point out, are members of "binary1 systems': two stars revolving around a common center. Some of these binary ystems contain stars that are doomed eventually to explode as supernovae. When the supernova in the binary blows up a large part of its matter is shot out t the system, even out of the galaxy ltsel| Some of the hot gas emitted toward the end of the explosion, however does not move quite fast enough. Part of it comes near the companion star (in the local case, the sun), and is captured by it (see diagram). It forms a gaseous ^ which gathers into loose clots that eventually break up into planets, satellites, asteroids, and all the other oddments that constitute a planetary system.

Foster Mother' These null are made argely of heavy elements, not of hydrogen and helium like the sun. This is natural enough, says Hoyle. The supernova blows up just after (and because) it has produced within itself a large amount of heavy elements. As for the nucleus of the supernova, the martyred mother of plans, it recoils out of the system as a dim white dwarf, leaving the companion star in charge of its offspring.

Since the sun, once the companion star of a supernova, is an average, conservative citizen of the galaxy, it will probably take good care of its adopted planets for quite a while. In about ten billion years however, thinks Hoyle, it will begin to get hotter, frying its planets clean of life After some 50 billion years, it will swell up monstrously and consume the inner ones (including the earth). Eventually it will fade slowly, first to a white dwarf hen to a black dwarf, and cruise through space in darkness, surrounded by its dead outer planets.

As Hoyle points out, the number of spendthrift stars in the local galaxy can be calculated, and also the number that happen to be members of binary systems. He figures that nearly ten million such stars have blown up since the Milky Way galaxy formed its first stars nearly four million years ago. Each explosion, he thinks, gave birth to a brood of planets not very different, except in details, from the solar system.

Pseudo-People. None of these systems can be seen with telescopes (nor are they likely ever to be seen), but Hoyle believes that at least 100,000 of them must each contain at least one planet with physical conditions (temperature, chemical content, etc.) favorable to the development of life. The question whether life will develop where life is possible he leaves to the biologists, but he thinks their answer would be yes. He suspects, too, that life on faraway planets may have evolved along familiar lines. There may be "pseudo" men & women with two legs, two hands, large brains and two eyes--for all these bodily features have inherent virtues of which evolution may well have taken advantage.

No matter how interesting planets may be as niches for intelligent life, they are mere dust specks on the cosmological scalf. Hoyle and his Cambridge theorists are more concerned with the origin of the stuff out of which the galaxies were formed. When they consider such matters, they zoom to levels of mathematics where few can follow.

Back in the late '20s a discovery was made by California's Edwin Hubble and others (TIME, Feb. 9, 1948) that threw cosmology into a confusion from which it has not yet recovered. Hubble showed that the galaxies in far-off space, judged by spectroscopic analysis of their light, are rushing away from the solar system at speeds directly proportionate to their distances. The farther away they are, the faster they are moving. At an easily calculated-distance (about 2 billion light-years), the galaxies must be receding at the speed of light itself. No matter how big his telescopes may grow (the 200-inch on Palomar Mountain can penetrate half that distance), an earthling will never see such galaxies. They are speeding awa.y too fast; their light can never reach the earth.

Monkey Business. Why are the galaxies receding? Some cosmologists have suggested an enormous explosion that blew all the matter in the universe away from a common center. The chief thing wrong with this theory is that the galaxies are moving too fast; simple calculations show that^ they would have had to start their motion at a point so close in time that the whole universe would turn out to be younger than such minor parts as the stars and the earth.

Other cosmologists "monkeyed with gravitation," as Hoyle puts it, suggesting that it pulls now one way, now the other way, making the universe expand and contract alternately. Some "monkeyed" with time, too. None of these early theories settled the question of the galaxies in flight.

Hoyle's Cambridge colleagues, Bondi and Gold, approached the problem of the receding galaxies from an entirely different angle. They started with the assumption, based on philosophical-mathematical reasoning, that the universe must be in a "steady state," not blowing itself to nothing. Then they looked for something that was keeping it steady.

Continuous Creation. According to Einstein's relativity, four-dimensional space (three dimensions plus time) is in a sense "curved," and its curvature and therefore its "size" depend on the amount of matter within it. If more matter were added, space would have to stretch, carrying the galaxies with it. Why not, asked Bondi and Gold, figure out how much matter would have to be added to make the galaxies recede at the observed rate? The answer, dragged from thickets of mathematics, came out very simple. One atom of hydrogen, they calculated, must be added to each quart of space every billion years.

Hoyle, working on the same problem, approached it from the other end. In calculating how galaxies form, he assumed that all of space is filled with very thin hydrogen, about one atom per cubic inch. This gas is depleted, of course, when galaxies condense from it. But Hoyle was convinced that galaxies are forming continuously. So he calculated how much hydrogen must be supplied to keep up the formation of galaxies. His answer came out very close to the answer of Bondi and Gold. This check convinced both parties that the "continuous creation" of hydrogen in space is an actual fact.

Continuous creation? To many people the very idea seems startling or even shocking. Hoyle and his colleagues do not consider it so. It should not be more difficult to accept, they argue, than the common belief that the universe was created all at once in the distant past. In their own words, the hydrogen "just appears." Where it comes from they do not know, or if it comes from "anywhere" in the ordinary sense. Perhaps, they admit, man will never know. In any case, they leave to the theologians the capitalized word Creation to explain the genesis of the whole physical system that their theories describe.

The disappearance of the receding galaxies is a similar phenomenon and just as remarkable, in their view. Where the galaxies go, if "anywhere," they do not know. When they reach the speed of light with the stretching of space, they "just disappear." The mass of those that go "over the edge" of perception equals exactly the mass of the newly created hydrogen. In the same way, the water spilling out of a full tank equals the new water entering it.

Cheery Universe. The universe of continuous creation, Hoyle believes, is a very cheerful place compared with earlier conceptions. Most early theoretical universes were dismally "running down." Eventually, the older cosmologists thought, all space would be uniform and dead. There would be no light, no life, no motion except the random wanderings of faintly warm molecules.

Hoyle's universe, which will never run down, is being constantly refueled with young, virgin hydrogen. Out of it new galaxies form, and new stars sparkle within them. New supernovae explode. New planets are born, and new life spreads like lively green mold over their fresh surfaces.

More hydrogen keeps appearing to replace that which condenses. Galaxies are never so thick that they clog the universe, for the addition of new hydrogen makes space "stretch" more & more. Adjacent galaxies move apart, and when they have moved enough, new galaxies form out of new hydrogen in the newly stretched space between them.

Cheers & Tuts. For years the theories of the Cambridge men were published piecemeal in the solemn little papers through which cosmologists communicate. They made very little stir. For one thing, English universities shy away from publicity, and Hoyle and Lyttleton were young.

This year the British Broadcasting

Corp. asked Hoyle to give a series of talks about "The New Cosmology" on the BBC's Third Program, aimed at some 300,000 highbrow listeners. In spite of the difficulty of his subject, Hoyle made an extraordinary hit. Audience approval, measured by BBC's sampling system, gave him a record-breaking rating. When the lectures were repeated on the Home Service for 3,000,000 listeners, the middlebrows liked them too. Published in book form, they have sold 60,000 copies, phenomenal for a scientific work.

Applause from professional colleagues was not as loud; there have been more tut-tuts than cheers. Many British astronomers deplore Hoyle as cocky (which he is) and as disrespectful toward his elders (which he also is). Specific objections to the Cambridge theories, however, have been few. The reason, Hoyle says bluntly, is that few astronomers know enough physics and mathematics to understand what he is talking about.

* Hoyle's The Nature of the Universe (Basil Blackwell; 5 shillings), to be published in the J.S. this spring by Harper.

* One lightyear, the distance light travels in a year, equals six trillion miles. /- And the earth was without form, and void: and darkness was upon the face of the deep --Genesis 1:2.

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