Judging Einstein

Before most physicists would believe the claims of relativity, they required proof—which would come in the form of a solar eclipse

J. Donald Fernie

This year we celebrate the centenary of Albert Einstein's special theory of relativity. Indeed, 1905 was the year in which Einstein first gave notice of his astonishing abilities. He was but 26 and had just earned his doctorate, but that year he published four papers on separate topics, each of which marked a major advance in physics. The first of these, on the photo-electric effect (the subject of Roald Hoffmann's Marginalium in the previous issue), would bring him the Nobel Prize, but it was the third, on special relativity, that made him both famous and controversial. A decade after this flurry of papers, in 1915, he unveiled the theory of general relativity, shaking again the foundations of science.

To test predictions of Einstein's theories... So different was relativity from the prevailing beliefs that most physicists demanded proof that it could explain phenomena that Isaac Newton's canon could not. Satisfying such demands was difficult, because the difference between the two models could only be apparent under extreme conditions. There seemed little hope that any terrestrial experiment could decide between them, but Einstein later identified three astronomical tests. The first was the proper calculation of the orbit of the planet Mercury—a feat that was beyond Newtonian physics (see "In Pursuit of Vulcan" in the September-October 1994 American Scientist). The second test required the comparison of light emitted from atoms in the Sun with light from similar atoms on Earth—relativity predicted that the Sun's light would have a longer wavelength (an example of the so-called redshift). The third test posited that if relativity was true, then rays of starlight that passed near the Sun would be bent compared to the same rays when the Sun was elsewhere in the sky. In each case, the relativistic effects are caused by gravity from the Sun's huge mass.

Early attempts to perform these tests did not silence Einstein's critics, because some observations supported his theory and others did not. Thus, the general theory of relativity yielded a much better solution to the Mercury problem than did Newtonian models, but another prediction of relativity, the redshift of the solar spectrum, could not be verified. (Eventually, astrophysicists learned that several other factors complicated the observation of this phenomenon.) So with one result in favor and another in doubt, the third test became something of a deciding vote for or against relativity.

Einstein first suggested how this light-bending effect could be measured in 1911. He predicted that those rays of starlight that passed closest to the Sun would be deflected by 0.85 arcseconds (0.00023 degree) because of the Sun's gravitational field. However, stars that appear next to the Sun are only visible during a total solar eclipse. To test Einstein's hypothesis, one would have to take photographs during an eclipse that showed background stars near the Sun's disk and compare them with photos taken months earlier or later, when the same stars rose in the night sky. Did stars appearing on opposite sides of the Sun's disk maintain the same spacing when the Sun was gone, or not?

This prediction seemed easy to check. Many pictures of solar eclipses already existed, as did photos of the night sky. Even so, skepticism about Einstein's theory was so prevalent that few astronomers rushed to their archives. And when they did examine previous photographs of solar eclipses, they found that the pictures were unsuited to proving or disproving Einstein's claim: The telescopes had been set to track the Sun's motion across the sky, not the stellar motions, and the slight differences between these perspectives obscured the small, predicted shifts in star positions. However, as time went by and other experiments gave equivocal results, the solar-eclipse experiment represented the best chance to test the truth of relativity.

Hoping for a Dark Noon

As early as 1912 it seemed possible to capture the necessary photographs with little fuss. In October of that year, a total solar eclipse was to run across the northern parts of South America, and the astronomical observatory of Córdoba in central Argentina was near enough to mount an expedition. Unhappily, almost all of South America was under clouds that day.

Another suitable eclipse loomed in August 1914, running northwest to southeast across eastern Europe. Erwin Freundlich, a young German astronomer, was determined to test Einstein's theory but encountered grave difficulty raising money for the trip. The scientific establishment in Germany was uninterested in paying for it, leading Einstein himself to offer his own none-too-abundant finances. With so few options, Freundlich appealed to other countries for collaborators that would help fund the expedition. He had only one taker: William Wallace Campbell and a team from the Lick Observatory in California. Later, the Berlin Academy provided additional support.

The eclipse was due August 21, but the team of Germans and Americans established a camp near Kiev well before that date to prepare for the event. Unfortunately, history intervened: On August 1, 1914, Germany declared war on Russia, and the German astronomers were taken prisoner. Russian forces expelled the older scientists and held the younger ones as prisoners of war. The Russians did allow the Americans to stay for the eclipse, but again the sky was totally clouded out. Campbell later wrote "I never knew before how keenly an eclipse astronomer feels his disappointment through clouds. One wishes that he could come home by the back door and see nobody."

The next year, at the height of the First World War, Einstein published his general theory of relativity. This timing greatly complicated the theory's dissemination because German scientific journals were then unavailable to the English-speaking world. It was an astronomer from neutral Holland who brought word of the new theory to Britain. Moreover, Britain was going through a period of almost hysterical opposition to all things German. Ardently opposed to this mindless, pervasive hatred, a young British astrophysicist named Arthur Stanley Eddington stood almost alone. Eddington was not only a rising star in astronomy but a Quaker—a religious pacifist. As such, he refused to fight in the war, although he was willing to risk his life providing aid to civilians caught in the violence. Because of his beliefs, Eddington lived on the verge of imprisonment during much of the war and suffered vicious attacks for his pacifism and efforts to counter his peers' nationalistic hostility toward German science.

Eddington learned of Einstein's general theory from the Dutch astronomer Willem de Sitter and was immediately taken with it. He was almost certainly the first (and, for a while, the only) English-speaker to understand the theory and appreciate its significance. Eddington grasped the fact that Einstein's new work meant that the eclipse experiment was an even more significant test of relativity—the general theory predicted twice as much deflection of light rays passing the Sun as did the special theory. Another suitable eclipse would occur in 1919, and although in 1915 there was no immediate hope for peace, the British Astronomer Royal, Frank Dyson, began to lay plans (no doubt at Eddington's prompting) for an expedition to photograph the event. Eddington, of course, was eager to lead such an expedition but worried that his uncertain standing with the authorities might cause difficulties for the project. Then, in a stroke of genius, Dyson wrote a carefully worded letter to officialdom. In response, the government notified Eddington that he was lucky so far in having avoided prison, and that his only hope of remaining that way was to lead Dyson's expedition, whether Eddington liked it or not! Eddington dutifully bowed to the hoped-for ultimatum.

Partly Cloudy

Around the same time, an eclipse in the United States in June 1918 was almost entirely obscured by clouds, but Campbell's team did get some photographs. These poorly exposed plates seemed to indicate no relativistic effects, much to the delight of Einstein's skeptics, including Campbell.

The eclipse of May 29, 1919, was to start near the border between Chile and Peru, then traverse South America, cross the Atlantic Ocean and arc down through central Africa. No part of the path was far from the equator, and the desirable, longest-lasting portion was in the Atlantic, a few hundred miles from the coast of Liberia. The British planners decided that the tiny island of Principe, nestled in the crook of Africa's Gulf of Guinea, would be best despite the poor astronomical viewing from low-lying tropical regions. The choice of Principe introduced other challenges. One modern travel agency advises prospective visitors to the island that "It's best to go between June and September. The rest of the year is muggy and hot—you'll be swimming in rain and your own sweat." Just in case Principe was cloudy at the crucial time, the British sent a second expedition to observe the eclipse from Sobral, in eastern Brazil.

The main instruments at both sites were existing astrographic telescopes of 33-centimeter aperture designed specifically for photographing star positions with high precision. Although these telescopes were designed to automatically follow the stars, their temporary emplacement in the field required each telescope to be immobilized as a clockwork-driven flat mirror tracked across the sky and fed light to the main lens. As an afterthought, the Brazil contingent added a small 10-centimeter telescope to its roster. In the end, it saved the day.

The expeditionaries set out months ahead of the eclipse to allow for travel difficulties. Although the war officially ended in November 1918, chaos continued for months thereafter. Upon arrival, they had to evaluate the terrain, choose a site, and set up and test their equipment. Eddington's group arrived at Principe in late April and, amid the heat and rain, found themselves under such constant attack by biting insects that they needed to work under mosquito netting most of the time. The rain grew worse as May advanced, and the day of the eclipse began with a tremendous storm. The rain stopped as the day wore on, but the totality phase of the eclipse would start at 2:15 p.m. and last only five minutes. Eddington wrote:

About 1.30 when the partial phase was well advanced, we began to get glimpses of the Sun, at 1.55 we could see the crescent (through the cloud) almost continuously and large patches of clear sky appearing. We had to carry out our programme of photographs in faith. I did not see the eclipse, being too busy changing plates, except for one glance to make sure it had begun.... We took 16 photographs ... but the cloud has interfered very much with the star images.

The weather in Brazil was much better—beautifully clear, in fact. The observers took 19 photos with the astrograph and eight with the small telescope. But when the photographs were developed, they found that despite their precautions, the astrograph's pictures showed, according to Dyson, "a serious change of focus, so that, while the stars were shown, the definition was spoiled." Even under ideal conditions, the predicted relativistic displacement on the photographs was only 1/60 of a millimeter—about a quarter of the diameter of a star on a sharply exposed image. Although they could measure such a minute shift, the poor focus made this task nearly impossible. By contrast, the small telescope's photographs were clear and sharp, but on a reduced scale.

Weighing the Data

Many months later, back in England, Eddington pondered the inconsistent results. Einstein's theory predicted a displacement of 1.75 arcseconds, but none of the experiments was in perfect agreement with the theory. The usable photos from Principe showed an average difference of 1.61±0.30 arcseconds, the astrograph in Brazil indicated a deflection of about 0.93 arcseconds (depending on how one weighted the individual spoiled photos), and the little 10-centimeter telescope gave a result of 1.98±0.12 arcseconds. The smaller device, in addition to yielding the most precise data, afforded a wider field of view and supported Einstein's theory of how the displacement should vary with angular distance from the edge of the Sun. But the validation of relativity required exact measurements, particularly because physicists had realized that Newtonian theory alone could predict a stellar displacement that was half that of Einstein's, or about 0.83 arcseconds.

Eventually, Eddington, after much discussion with Dyson, suggested an overall measurement of 1.64 arcseconds, which he took to be in pretty good agreement with Einstein, but he also gave the separate results from each telescope so others might weight them as they saw fit. Moreover, Dyson offered to send exact contact copies of the original photographic glass plates to anyone who wished to make their own measurements, which should have gone far to refute the occasional allegation that Eddington had cooked the results.

Ironically, confirmation of Eddington's conclusion (and the theory of relativity) came from Campbell's team at an eclipse in Australia in 1922, for which they determined a stellar displacement of 1.72±0.11 arcseconds. Campbell had been open in his belief that Einstein was wrong, but when his experiment proved exactly the opposite, good scientist that he was, Campbell immediately admitted his error and never opposed relativity again.

Acknowledgment
I am indebted to Dr. Jeffrey Crelinsten for granting access to his unpublished work on this topic and for providing comments on an earlier version of this article.

Bibliography

• Clark, R. W. 1971. Einstein: The Life and Times. New York: World Publishing Company.
• Crelinsten, J. In press. Einstein's Jury: The Race to Test Relativity. Princeton, New Jersey: Princeton University Press.
• Stanley, M. 2003. An expedition to heal the wounds of war: The 1919 eclipse and Eddington as Quaker adventurer. Isis 94:57-89.

Obituary: Sir Joseph Rotblat

Nuclear physicist and Nobel peace prizewinner who quit the Manhattan Project and whose Pugwash initiative helped thaw the cold war

GO Jones
Friday September 2, 2005
The Guardian

Sir Joseph Rotblat, who has died aged 96, was a nuclear physicist and a tireless worker for peace. When he and his creation, the Pugwash Conferences on Science and World Affairs were jointly awarded the 1995 Nobel peace prize, some newspapers identified him only as a "little known" physicist. But scientists in many disciplines, and officialdom in many countries, knew him well.

Born in Warsaw, Poland, Rotblat remained there until the age of 30, during which time he had been working in nuclear physics. What saved his life was that he had arranged to spend a year as Oliver Lodge fellow at Liverpool University with the Nobel prize for physics recipient Professor James Chadwick - the man who proved the existence of neutrons. This meant that Rotblat, after a short return visit, left Poland two days before Hitler invaded his country, otherwise one of the most extraordinary scientific careers of the 20th century would have been lost.

In the year 1939 came the discovery of nuclear fission in uranium and Rotblat himself subsequently worked on fission, briefly in Warsaw and later in Liverpool, where certain basic experiments were carried out into the feasibility of an atomic bomb. Inevitably, with the entry of the United States into the second world war in 1941, and the subsequent move to develop the A-bomb, he soon found himself at the centre of the Manhattan Project at Los Alamos, New Mexico.

Like a minority of the scientists involved, he was concerned then about the morality of working on a weapon of mass destruction, but convinced himself that the apparent danger of a German bomb justified it. However, unlike those other scientists, as soon as this danger had clearly disappeared he left the project and returned to Liverpool University to resume his post as a lecturer, and then senior lecturer, in the physics department and director of research into nuclear physics.

In 1950 he became professor of physics at London University's St Bartholomew's Hospital Medical College. He remained in the post until 1976 - then becoming emeritus professor. During those years his professional career was devoted to the application of nuclear physics to medicine.

But Rotblat's real life's work was summed up by Bertrand Russell in his autobiography: "He can have few rivals in the courage and integrity and complete self-abnegation with which he has given up his own career (in which, however, he still remains eminent) to devote himself to combating the nuclear peril as well as other, allied evils."

Rotblat first took the lead in setting up, in 1946, the British Atomic Scientists Association (Basa), following meetings between Liverpool and Oxford physicists who had worked on the Manhattan Project or its British precursor, code-named Tube Alloys.

Although Basa was much smaller than its counterpart, the Federation of American Scientists, it was able to stimulate public debate through its journal, through public statements and its atom train travelling exhibition. It had adopted a non-political stance and its list of vice-presidents - all fellows of the Royal Society - included many of Britain's most eminent scientists as well as government advisers, and covering almost the whole political spectrum, from critics of British defence policy like Patrick Blackett to Winston Churchill's personal scientific adviser, Lord Cherwell.

Unfortunately, it turned out to be insufficiently non-political for some of the vice-presidents, following a public statement in 1957 about the danger of strontium-90 in fallout from nuclear weapon tests. Basa was wound down and finally dissolved in 1959. Many of Britain's leading physicists, including Harrie Massey, Nevill Mott, Rudolph Peierls and GP Thomson, had taken active roles in it. But Rotblat was its driving force and conscience.

By this time Rotblat had become active in other directions. He had helped Russell and took the chair at the launch of the famous Einstein-Russell Manifesto in 1955, signed by Albert Einstein two days before his death, and by nine other world-famous scientists, mostly Nobel prizewinners. At the time of his death, Rotblat was the last surviving signatory. He was a founder member of the Campaign for Nuclear Disarmament, launched in 1958, and was briefly on its executive committee.

Rotblat's main contribution, nevertheless, was still to come. It was through the Pugwash Conference on Science and World Affairs, financed by a Canadian-American industrialist, Cyrus Eaton, which was first held in 1957 at Pugwash, a small fishing village in Nova Scotia.

Conferences followed approximately once a year, organised by Rotblat and his friend Professor Patricia Lindop of St Bartholomew's. The lists of up to 100 participants, from as many as 40 countries, but mostly from Great Britain, the US and the Soviet Union were a Who's Who of international science; the list of locations is a map of the world.

Most significant was the understanding that participants attended as individuals, not as representatives of governments, though observers from such organisations as the UN or the UN's educational scientific and cultural organisation Unesco were welcome. Scientists from both sides of the iron curtain could talk freely and informally but could, of course, report back to their governments. A Unesco/Pugwash symposium: Scientists, The Arms Race And Disarmament (1982), mentions several instances where Pugwash discussions had clearly contributed to subsequent international agreements.

Rotblat was secretary-general of Pugwash from 1957 until 1973, chairman of British Pugwash from 1978 to 1988 and from 1988 to 1997 president of Pugwash worldwide. Its annals, many edited by him with various collaborators, have provided continuing and wide-ranging analyses into current problems of disarmament and world security.

While working at Los Alamos, Rotblat had been shocked to hear General Leslie Groves, director of the Manhattan Project, remark quite casually that the real purpose, of course, was to subdue the Soviet Union. When he decided to leave the project, a determined but highly incompetent attempt had been made to "fit him up" as a Russian spy.

It is a tribute to his universally recognised integrity, and to his skill in treading delicately though forcefully (he was very much aware of the cost of respectability as well as of its advantages) that among his many honours from east - including several from his native Poland - and west was the CBE, awarded in 1965. No measure of his real contribution, the honour at least signalled that his help to the British establishment by then outweighed his nuisance value.

In 1992, jointly with Hans Bethe (obituary, March 18 2005), he was awarded the much coveted Einstein peace prize, and in 1995, unusually late in career for a distinguished scientist, he was elected to the Royal Society. But perhaps the accolade that meant most to him was the sometime Soviet leader Mikhail Gorbachev's statement that Pugwash papers and conferences had helped to guide the foreign policy that had led to the thaw in the cold war.

Rotblat wrote or edited more than two dozen books and scores of papers, culminating in the 1995 Nobel lecture - a powerful and moving exposition of the continuing danger to the world of the existence of nuclear weapons. In it he appealed to the nuclear powers to abandon cold-war thinking, to his fellow scientists to remember their responsibility to humanity, quoting the last passage of the Russell-Einstein Manifesto: "We appeal, as human beings to human beings. Remember your humanity and forget the rest. If you can do so, the way lies open for a new paradise; if you cannot there lies before you the risk of universal death."

Rotblat continued to work into his 90s with apparently undiminished energy, lecturing in dozens of cities in Britain and abroad - including Hiroshima and Nagasaki.

Since his Nobel prize, he was aware that he was now "somebody" - his own expression - and spoke out on wider issues. In 1996, he appealed personally to President Weizman of Israel to show clemency to Mordechai Vanunu, the former technician who had "leaked" to the Sunday Times about Israel's secret stockpile of nuclear weapons and was then still in prison - in solitary confinement - after 10 years.

Following the disclosures about cloning experiments, he argued that an international ethics committee must be set up to monitor developments. He said: "I feel, however unpleasant it may be for scientists, that science may have to be controlled. We have got to tackle it because I think the whole future of mankind is in jeopardy."

Anthony Tucker adds: In accounts of Joseph Rotblat's important work for the wartime Tube Alloys Project (the British nuclear weapons programme) at Liverpool University, of his time at Los Alamos, his reasons for leaving the project and turning to the much harder battle for peace and disarmament, Rotblat consciously excluded all references to his life before the war. He called such references "extraneous personal elements", almost as if his life had begun when he left Poland in 1939.

Yet his life and attitudes had, by that time, been profoundly affected by isolation, family disruption and social deprivation. After the turn of the century, his father built up and ran a nationwide and prosperous horse-drawn transport business based in Warsaw. The family owned land and bred horses out in the countryside and, with two brothers and a sister, Joseph's formative years were initially in a context of culture, comfort and social esteem.

When he was five, things changed dramatically for the worse. The first world war turned Europe into a charnel house triggering, among other things, a wave of antisemitism that swept away his family's business and position. Rotblat grew up as an increasingly deprived, often hungry and sometimes physically abused child in the breadlines of a starving nation. Experiencing first-hand the near-insane intolerance and injustice generated as a political condition of war, these years forged Rotblat's unswerving ideals of world peace and of the use of science for the benefit of man and the planet.

In spite of great difficulties, the family remained together in Warsaw and, by 1918, Joseph was reading everything he could find, in English as well as Polish and Russian. His parents, recognising his outstanding intelligence, wanted him to become a rabbi. But Joseph, with a natural gift for mathematics and a flair for experiment, was determined to become a scientist.

During the early interwar years, he scratched a living as a teenage domestic electrician in Warsaw and, through sheer brilliance - for he was without formal education -won a very rare free place in the physics department of the University of Warsaw. At the same time he was granted a position as junior demonstrator, which carried a pittance rather than a salary. In spite of - or perhaps because of his experience of poverty - he never looked back academically, becoming a research fellow at the university in 1933 and assistant director of the atomic physics institute at the Free University of Warsaw from 1937 to September 1939.

During this period he married but, when he left Poland for Liverpool University on the eve of the outbreak of the second world war, his wife was ill.

They planned that she should follow him to England as soon as she was able. In the event she was killed, or died in the appalling conditions of the Warsaw ghetto during the first months of the Nazi occupation, a fact known to British intelligence in 1941 but not passed on to Rotblat until 1945.

Indeed, when he left Los Alamos in 1944, Rotblat had planned to return to Poland immediately after the war in the hope of finding his wife. Instead, in recognition of the important role Rotblat had played in nuclear weapons research, the British government agreed to try to find any other survivors of his family.

Rotblat thought that his parents would be dead. But his mother, sister and two brothers, who had escaped from the Warsaw ghetto to go into hiding or join the anti-Nazi guerrillas in Russia, were found to be alive. By negotiation and by devious routes, all were brought to England in the postwar years, cementing Rotblat's loyalty and, through their experiences, reinforcing his unceasing and single-minded pursuit of an ideal world in which the primary goal is peace.

In his 90th year Rotblat might be said to have finally entered the public consciousness by appearing on BBC Radio 4's Desert Island Discs.

In 1998, he surprised some of his friends by accepting a knighthood at the level (Knight Commander) usually associated with establishment figures such as lords lieutenant or permanent secretaries. But all will have appreciated the words of the citation: "for services to international understanding".

• Anthony Tucker died in 1998. His contribution has been revised and updated.
• Joseph Rotblat, nuclear physicist and peace campaigner, born November 4 1908; died August 31 2005

Guardian Unlimited (c) Guardian Newspapers Limited 2005

C. de Oro academics rant over education budget cut, join calls for Arroyo's ouster

By Maricel Casino-Rivera
The Mindanao Goldstar Daily
Volume 16 No. 41

A GROUP of academics from major colleges and universities in Cagayan de Oro yesterday joined militant youth groups in calling for the ouster of the embattled President Arroyo as the Lower House resumed deliberations on the impeachment complaints.

This came even as a handful of students gathered in front of the Jesuit-run Xavier University, braving the heat at noon-time, to pursue their call for Arroyo's resignation.

Academics who call themselves the Educators' Caucus, an informal gathering of teachers and other education workers coming from private and public education institutions in the city, said they were dismayed over the sorry state of the country's education system. The group includes academics from Xavier, Mindanao Polytechnic State College (MPSC), Liceo de Cagayan University, Capitol University and Cagayan de Oro College.

The group said the government budget for education significantly decreased from 17 percent in 2002 to 14.9 percent this year.

In a statement, the organized academics said the government also reduced the education department's budget for maintenance and other operating expenses and services.

In 2004, they said there was an overwhelming lack of public teachers.

"The lack of budget for education led to massive contractualization of teachers, low quality of education due to increased number of working hours and number of class size and the decreased income for the teachers," their statement said.

Kim Gargar, MPSC Physics department chairperson, said the Educators' Caucus is a venue for discussions on issues that concern the education sector and promotes and forms the broadest unity among their ranks for their legitimate democratic rights and interests.

"It believes that as significant members of the academic community the educators are at the vantage point to observe, analyze and help solve the problems besetting the country," said Gargar.

Gargar said the group is also fully supporting the impeachment process. Its members have shown concern over reports that Malacanang was bent on using the alleged ill-gotten wealth of the Marcoses to influence the outcome of the impeachment hearings.

The Presidential Commission on Good Governance (PCGG) is finalizing details on the auction of the jewelry owned by former First Lady Imelda Marcos by the end of this year with an estimated value of US$10 million.

Gargar said it was time for Arroyo to go because the evidence--the "Hello Garci tapes"--clearly show that "she cheated and betrayed public trust to usurp power".

"The tapes [are] the last straw. From the first day she assumed office, her credibility has been questioned. The President has lost moral ascendancy, legal mandate and credibility to stay in power," said Gargar.

When you love someone

When you love someone you'll do anything
You'll do all the crazy things that you can't explain
You'll shoot the moon - put out the sun
When you love someone
You'll deny the truth - believe a lie
There'll be times that you'll believe
You can really fly
But your lonely nights have just begun
When you love someone
When you love someone you'll feel it deep inside
And nothin' else can ever change your mind
When you want someone - when you need someone
When you love someone
When you love someone - you'll sacrifice
You'd give it everything you got and
you won't think twice
You'd risk it all - no matter what may come
When you love someone
You'll shoot the moon - put out the sun
When you love someone

---------
I like the sound of the oboe.