Scientists, Looking Ahead, Mark Einstein's Centennial
Walter Sullivan
Planned celebrations marking centenary of Albert Einstein's birth described; they include internatl symposium, Jerusalem, ceremony in Berne, Switzerland, where Einstein worked on his relativity theories, and meetings in Ger, where Einstein was born in Ulm; recent meeting at Inst for Advanced Study in Princeton was followed by one at Hotel Roosevelt, NY, sponsored by NY Acad of Sciences; experts' comments noted; reproduction of page of Einstein's last calculations before death in '55; drawing of Einstein (M)
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To mark tomorrow's centenary of Albert Einstein's birth, scientists throughout the world are celebrating a profound revolution in human understanding of nature — the formulation of theorie accounting for the release of nuclear energy and the slowing of time one warping of space by gravity.

Celebrations are being held at places that figured prominently in Einstein's career. They include Berne, Switzer land, where he was working in the patent office when three of his most important theories were published in 1905, and Jerusalem, where an international symposium will begin tomorrow. Einstein was an ardent Zionist and once was offered the presidency of Israel. Ultimately, the Hebrew University in Jerusalem is to receive his literary estate.

Meetings also are planned in Germany. where Einstein was born at Ulm on March 14, 1879, and at Southern Illinois University in Carbondale. In addition, a major Einstein exhibit has been organized by the Smithsonian Institution's National Museum of History and Technology in Washington.

But, in addition to looking at the accomplishments of the past, scientists are using the anniversary to take stock of the stubborn paradoxes and challenges that remain. Last week, for example, a number of those who worked with Einstein or otherwise laid the foundations of modern physics among them Paul A. M. Dirac of Britain and a half‐dozen other Nobel laureates — explored those problems at the Institute for Advanced Study in Princeton, N.J., where Einstein spent his last years. That meeting was followed by a similar one at the Hotel Roosevelt in New York, sponsored by the New York Academy of Sciences.

The New Jersey symposium offered views on such subjects as continuing efforts to at‐hieve the unification that obsessed Einstein in the latter part of his life — a single theoretical framework that would explain all natural phenomena, perhaps even life itself.

The participants also debated such philosophic and scientific questions as the role of human intervention in “creating” the laws of nature. They discussed how the universe was born and how it might end, and they talked about the destiny of sentient beings in an ever‐expanding universe.

They marvelled at evidence that the universe is essentially uniform and homogeneous, despite its assumed birth in a catastrophic “big bang” billions of years ago.

And they pondered the perplexing “gates of time” discussed by Dr. John A. Wheeler of the University of Texas. One gate, the hypothesis goes, would be when time began — at the precise moment of the “big bang.” The other would terminate time in a “big crunch,” assuming that the universe reverses its expansion and collapses.

The scientists also worried about the possibility of “naked singularities” and time reversal, where causality breaks down.

Einstein's relativity theories show that, in a sense, it is possible to travel into the future. For instance, if an astronaut were to journey far into space and then return, having accelerated almost to the speed of light, he would find his generation of human beings dead and forgotten.

The validity of that effect has been demonstrated in many ways. What troubles theorists is the difficulty of proving that travel into the past is intrinsically impossible. Dr. Paul Davies, a specialist in relativity theory at King's College, London, discussed such time‐travelers, or “temponauts,” in a recent issue of the journal Nature. The thought of visiting one's own past, he said, “causes physicists headaches, for it plays havoc with causality. Suppose a time traveler kills his parents before his birth?”

Dr. Stephen W. Hawking of the University of Cambridge in England said that the same sort of problem arises if it becomes possible to breach the information barrier that surrounds a black hole. A black hole occurs when matter becomes sufficiently concentrated to create a gravity field from which nothing, not even light, can escape.

It was originally postulated that such situations could arise when a massive star collapses after its nuclear fires have burned out and there is no longer heat or radiation to support its gaseous envelope.

Prediction on Gravity

Einstein's prediction that strong gravity, such as that near the sun, would bend space and slow time was demonstrated in the 1919 eclipse of the sun. This implies that the extremely powerful gravity in a black hole would stop time completely and curve space in upon itself. Collapse within the hole would procede to a “singularity” of infinitesimal volume and infinite density.

If, Dr. Hawking said, the universe was born from such a singularity, as many theorists believe, then “we can regard what came out of it as the initial data for the universe.” Does this implication that information can come through a singularity from “somewhere else” mean that every time a star collapses to a singularity the same thing can happen, allowing alien rules and regulations to enter our universe?

“Fortunately,” he said, the information barrier enveloping a black hole —the intense gravity that prevents the escape of virtually anything — seems to rule this out, although the integrity of that barrier remains “the major unproved conjecture in classical general relativity.”

Dr. Freeman J. Dyson of the Institute for Advanced Study suggested that Dr. Hawking's black hole theories would prove to be the most important theoretical advance since Einstein formulated his famous equation E=Mc2.

Meaning of Formula

The latter says that if mass is converted to energy, the energy released (E) equals the mass (M) multiplied by the speed of light squared (c2). In atomic bombs and atomic power plants, enormous amounts of energy are derived in this way from the conversion of very little mass.

In the view of many theorists, Dr. Hawking's analysis of black holes has brought together what until now were two seemingly disparate aspects of physics. These are general relativity (governing large‐scale phenomena involving gravity) and quantum theory, which is applicable only on the atomic level.

In quantum behavior, energy is transmitted in the form of individual packets, or “quanta.” When any one atom will radiate a quantum seems unpredictable, yet the rate at which such events will take place — their probability of occurrence — in a large assemblage of atoms can be precisely specified. It was this indeterminacy on the atomic level that most deeply troubled Einstein, and a month before his death in 1955 he termed it dubious that field theories, such as those of relativity, could ever account for quantum behavior.

Dr. Hawking is credited by some specialists with baying bridged the gulf between field theory and quantum behavior by showing that, through a quantum effect known as “tunnelling,” black holes can radiate particles able to escape their otherwise inescapable gravity.

The black hole concept was first spelled out by Dr. J. Robert Oppenheimer and his colleagues in 1939, but — as noted by Dr. Hawking — many theorists, including Einstein and that early champion of relativity, Sir Arthur Eddington, did not believe in it.

Dr. Dennis Sciama of Oxford University said at the Princeton meeting that Einstein would have chosen to “change physics,” rather than accept so radical an implication of his own theory. Only when it was found that stars have, in fact, collapsed to extreme density did the idea begin to win wide acceptance, although there are still many doubters.

Dr. Wheeler, the inventor of the term “black hole,” commented that there has never been a law of physics that did not require time and space for its expression. It can be assumed, he said, that inside a black hole, where time and space vanish, the laws we know may be quite different.

Among those who described the continuing efforts at unification was Dr. Yuval Ne'eman of Tel‐Aviv University, who discussed “supergravity” and “extended supergravity.” These are theories that seek to bring gravity into quantum theory, suggesting dimensions beyond those normally used to describe space and time.

Dr. Stephen Weinberg of Harvard University discussed possible unifications involving three of the basic forces: the electromagnetic force that drives electric motors, the “weak” force that causes radioactive atoms to emit electrons and the “strong” force that holds together the atomic nucleus_

Heand Dr. Abdus Salam'have independently formulated a theory combining the weak and electromagnetic forces, and the theory has been strongly supported by experiment.

Dr. Weinberg noted that a way has been developed to deal with the many quarks believed to form the heavier atomic particles and the “gluons” holding them together. Because the quarks seem to carry properties likened to colors, the method is known as quantum chromodynamics.

He believes it offers hope of bringing the strong force into the same framework as the weak and electromagnetic forces — a major advance toward Einstein's dream. The new theories imply that the proton, a particle found in all atoms, may be unstable, decaying at an extremely slow rate. He urged that experiments be carried out to test this hypothesis.

The confirmation that the proton the supposedly stable building block of all matter — can decay would be one of the most revolutionary developments in physics.