The Universe Won’t Keep Still

Press, Volume CV, Issue 31030, 9 April 1966, Page 12

The Universe Won’t Keep Still

(By

ROBERT COWEN,

National Science Editor of the “Christian Science Monitor”)

UNCOVERING the structure and history of the universe is a never-ending challenge. As soon as one layer of mystery is peeled back, a new perplexity is revealed.

Phenomena unknown a few years ago are being closely studied for clues to the underlying nature of the universe. Announcement of these discoveries, in some cases less than a year ago, has infused the debate over rival cosmic theories with unusual excitement.

As Dr. Geoffrey Burbidge of the University of California put it recently, “The history of this subject over the last four years has been that, as soon as a theorist explains something, then an even more baffling discovery is made.”

Nevertheless, cosmologists are generally convinced that their science has reached a stage where a shakedown competing theories is imminent.

Dr. Burbidge was one of several scientists who gave a progress report on this research at a special seminar sponsored by the American Institute of Physics and the National Association of Science Writers.

Here, briefly, is where the new findings are expected to help cosmologists make some decisions. One broad class of theories assumes that the universe was born in the violent explosion of a primordial mass and that it has been developing and expanding ever since. Just when this happened depends on which of these “big bang” theories you favour. Most would put it at least 10 billion years ago and probably much earlier. “Steady State” Opposed to these theories is a radically different concept. It envfsions a universe with no temporal beginning or end. It is a universe that remains more or less the same indefinitely. These “steady-state” theories do conceive of the universe as expanding. This is generally acknowledged to be an observed fact. As galaxies move away from each other in this expansion, new ones form to take their place and thus maintain the steadystate picture. These galaxies form from stars, which, in turn, condense from hydrogen that appears spontaneously in space. This assumption of spontaneous creation of matter is a distinctive feature Of steady-state theory. One way to decide between big-bang and steady-state views would be to find out what the universe was like long ago. If it was quite

different from what it now is, steady-state theories would be scrapped. Cosmologists think the new findings will help them learn what the ancient universe was like. Some of the discoveries are of objects thought by many experts to be so distant it has taken many billions of years for their light to reach us. They may show a quite ancient picture Of the universe.

Many of them are powerful emitters of both light and radio waves. Viewed with the 200-inch telescope on Mount Palomar, the faintest of them outshines the brightest galaxy 30-fold. Yet they are so small they appear no bigger than a nearby star. Brilliant Quasars These are the quasi-stellar radio sources, nicknamed quasars. Dr. Burbidge calls them “the most glamorous objects in the sky right now.” No-one knows what they are. If they are indeed billions of light years away, no-one can yet explain how they generate the enormous energies which enable them to shine so brightly over vast distances. The only way to estimate their distance is by means of the so-called “red shift.” Many quasars have been spotted by Dr. Allan A. Sandage of the Mount Wilson and Mount Palomar Observatories. Their red shifts were measured by his colleague Dr. Maarten Schmidt. Last April, Dr. Schmidt reported a quasar with a red shift indicating a runaway speed 80 per cent of the speed of light. Then, in June, Dr. Sandage reported a new class of very distant objects. They too, appear small and brilliant, But, unlike quasars, they emit no radio noise. For many years, they had been considered blue stars within our own galaxy. Now, Dr. Sandage said he thought them to be small, blue, distant galaxies. Big Bangs At that time he judged these galaxies to be 500 times more numerous than quasars, with a red shift indicating a Here, he said, was a type of object so plentiful that, along with quasars, it would soon give a good picture of the universe of long ago. Already he and others who support . big-bang theories thought they could see trends in the distribution of these objects that favoured their views.

Added to this was the announcement in May that Dr. Arno A.Penzias and Dr. Robert

W. Wilson of the Bell Telephone Laboratories had detected strange radio noise on the frequency band used by the Telstar communications satellite. This noise comes in from all parts of the sky. According to a version of big-bang theory

worked out by Professor Robert H. Dicke and others at Princeton University, such noise could be left over from the birth of the universe. The noise discovered at Bell laboratory is strong enough for its frequency to fit this theory. Under the onslaught of discovery, steady-stake theory began to come apart. In October, Professor Fred Hoyle of Cambridge University, the leading steady-state spokesman, published a piece in “Nature” saying, “It seems likely that the idea will now have to be discarded.” But the more its opponents have reached out for findings to crush the steady-state idea, the more the desired answers have eluded their questioning. For one thing, Dr. Burbidge told the seminar here that Dr. Sandage’s blue galaxies have turned out to be only 5 to 10 per cent as numerous as he first thought them to be. Second, it isn’t yet certain that quasars really are out near the edge of the universe. Rapid Changes Dr. Burbidge noted that many quasars show fluctuations in light and .radio output. Some changes take place in a matter of weeks. One showed a 40 per cent change in brightness in 20 days. Since no physical influence can move faster than light, this means that the volume in which such changes take place is on the order of a few light works in diameter. It is hard to imagine what mechanism can generate the enormous energy in such a small volume needed to make a quasar shine brightly from billions of light years away, Dr. Burbidge said. He added that, “We do have to consider that the objects may be ‘local.’ This would get around a lot of the trouble with energy production. Perhaps they are objects

thrown at high speed from galaxies ... a few tens of millions of light years away.” A British radio astronomer, Dr. Cyril Hazard, agrees more study is needed. He is working at Cornell University’s Arecibo, Puerto Rico, Center for Radiophysits and Space Research. With the help of the moon, he is using Arecibo’s 1000 ft diameter radiotelescope to make the most precise study of quasars yet undertaken. When the moon moves in

front of a quasar, the time when the object is eclipsed and when it reappears can be accurately clocked. . The position of the moon’s edge is known to within a hundredth of a second of arc. Knowing this, and with the precision of the Arecibo “dish,” Dr. Hazard can pin down a radio source to within a tenth of a second of arc. That’s like measuring the width of a dime seen edgewise at a distance of a mile.

All quasars Dr. Hazard has studied are complex. Their components are fairly widely spaced. This gives him a handle on their distance.

Dr. Hazard said that a resolving power of 0.1 second should enable him to check the separation of elements of a quasar at distances where such an effect should show up. If separation of sueh elements becomes constant or increases for fainter and fainter (and therefore presumably more distant) quasars, this would prove that these striking objects lie many billions of light years away. Puzzling Waves However, Dr. Hazard said he has so far studied six quasars. He has yet to see this effect. This is too small a sample from which to draw a conclusion. But his finding is ground for doubt that the quasars are at cosmologically significant distances. “I think a decision may soon be made on this question,” Dr. Hazard said. Even the supposed “primordial” radio waves came in for questioning. Dr. Philip Morrison of the Massachusetts Institute of Technology noted that the atmosphere would filter out all but a tiny fraction of such waves if they do exist. To assume the noise observed by the Bell physicists to be primeval radiation is, he said, “like finding a small string coming out of a tent and imputing the presence of an elephant on the end of it.” Most cosmologists still expect the new discoveries eventually will help them discard some of their theories. But right now, they face a panorama of perplexity.

For the past year, astronomers have felt they were about to break through to a new understanding of the cosmos. But basic riddles continue to baffle them. Here is a progress report on the search for meaning behind a spate of discoveries.