Posts tagged 'physics'
Reading Elaine Pagels’s new book, Why Religion? A Personal Story, brought back memories of my friendship with her husband Heinz Pagels. I met him in 1966 when he arrived at the Rockefeller University. I had no knowledge of his work but he struck me as a golden boy. He was very handsome and looked more like someone who might sing folk songs for a living than a theoretical physicist. He had been born in New York City in 1939 and attended Princeton. He then went to Stanford for his graduate work and took his PhD in 1965 under the direction of Sidney Drell. I recently looked at the paper they published and it still holds up. Heinz then spent a brief time at the University of North Carolina. I do not know how he found his way to the Rockefeller but there he was.
I am rereading Proust. If anyone asks why, I tell them the story of Franklin Roosevelt and Oliver Wendell Holmes. Roosevelt paid a visit to the aged Holmes to find him reading Plato in Greek. He asked him why and Holmes replied: ‘To improve my mind, Mr President.’
Jeremy Bernstein · Remembering Oppenheimer
With the death of Stephen Hawking and the discussion it produced on black holes it was a little surprising that there was little or no mention of the man who created the subject, J. Robert Oppenheimer, who died in 1967 at the age of 62. He often said that the J stood for nothing, but I have a copy of his birth certificate on which his first name is given as ‘Julius’. In his day Oppenheimer was the most celebrated physicist in the United States. His portrait had been on the cover of Time magazine and he was on first-name terms with much of the Washington establishment, until he lost his security clearance in 1954. It was said by people who had known him before that the experience changed him profoundly and he appeared diminished. He did not appear diminished to me when when I arrived at the Institute for Advanced Study in Princeton in 1957 and was ushered into his office. The first thing he asked me was what was ‘new and firm’ in physics. I was spared trying to give an answer when his phone rang. It was from his wife. ‘It was Kitty,’ he said when he hung up. ‘She has been drinking again.’
I had one encounter with Stephen Hawking. He came in the summer of 1989 to the Aspen Center for Physics and had the office next to mine. He travelled with an entourage with whom he could communicate with his voice synthesiser. His hands still worked well enough. He gave a full house public lecture and afterwards Sidney Coleman presided over a question session. Hawking had to type out all his answers on his voice synthesiser which took a lot of time. At one point Sidney said: 'You can have it fast or you can have it good.' If I had asked a question, it would have been: how did he come up with the idea of Hawking radiation? I have always found his paper hard going and have always marvelled at the simple result at the end. In A Brief History of Time he gives an account which explains the phenomenon but not the result.
Jeremy Bernstein · Classified Material
In my earlier years I had some dealings with classified material, enough that I was able to see how arbitrary, foolish and transitory security classification can be. That there may be information on somebody’s computer that was classified at some point in the past doesn’t necessarily have any relevance for national security. In summer 1958, I was briefly a consultant for the Rand Corporation in Santa Monica. I had a Q clearance, the most rigorous that the Atomic Energy Commission had. This enabled me to receive classified information on nuclear weapons on a ‘need to know’ basis. During most of my short stay I didn’t need to know anything, but one day the theory division leader descended on me with stacks of numbers he wanted me to add up on a Marchant calculator.
In a distant galaxy, long ago, a pair of black holes, each about thirty times more massive than our sun, began to orbit one another. Over the next several hundred million years, gravitational waves generated by their motion caused them to spiral together, slowly at first but gathering speed as they came closer and closer, until they were whirling about one another at the same rate as the blades in a kitchen blender. They eventually slammed together at about a third of the speed of light, emitting a last burst of gravitational waves before settling down to the sedate life of an ‘ordinary’ black hole.
Glenn Seaborg, Joseph W. Kennedy, Edwin McMillan and Arthur Wahl discovered element 94 in Berkeley in 1941. McMillan and Philip Abelson had discovered element 93 the previous year. When Martin Heinrich Klaproth isolated element 92 in pitchblende in 1789, he called it uranium after the recently discovered planet Uranus. The scientists at Berkeley named elements 93 and 94 after the planets Neptune and Pluto. The discovery of plutonium was kept secret until after the war. At Los Alamos it was called ‘49’. This did not help much since Klaus Fuchs gave all the details about the bomb to the Russians. The Germans also realised the value of element 94 for making bombs but they never could make a reactor to produce the stuff.
The Iran University of Science and Technology in Tehran was founded in 1929 as a school of engineering. It became a general technological institute in 1972. It now has more than a dozen departments with thousands of undergraduate and postgraduate students. Few if any American universities have a more complete list of undergraduate physics courses. Looking at the faculty reveals an interesting split. The senior professors all did much of their degree work abroad. One of them for example was an undergraduate at Columbia. The junior faculty, including one woman, all did their degree work in Iran. In another generation, it may be that all of Iran’s physicists will have been educated in Iran. No other country in the Middle East would show a demographic like this. Taken in the large this means that Iran has a serious scientific infrastructure, which must be taken into account in any negotiations over its nuclear programme. The notion that the country can be negotiated into a scientific stone age is nonsense.
Astronomers from the BICEP collaboration announced on 17 March that, using a modest-sized telescope near the South Pole, they had detected gravity waves that have been rippling through the cosmos since the Big Bang. This is extraordinary news for our understanding of gravity generally, and for our understanding of how the universe probably evolved during the earliest moments of its history.
Last month an international team of physicists and astronomers working with the Planck satellite released a remarkable set of baby photos: images of the universe taken with light emitted when it was a mere 378,000 years old, less than 0.003 per cent of its present age.
At five o’clock on Tuesday morning, Yasser Arafat’s body was disinterred in Ramallah and tissue samples extracted for analysis by French, Swiss and Russian scientists. One of the things they’ll be testing for is polonium poisoning. But can a meaningful result be hoped for eight years after Arafat’s death? The half-life of Po-210 in vacuo is 138 days (i.e. half the original Po-210 nuclei would decay on average in 138 days) but in the body it’s rather less, between two and three months (i.e. on average half the Po-210 atoms would have passed through the body after this time). Either way, a definitive result for Arafat would be difficult to obtain now, since after eight years the initial quantities of any Po-210 would be diluted by a factor of a million. As a spokesperson for the University of Lausanne's Institute of Radiation Physics has said, the traces of polonium they found on Arafat's clothes a few months ago could be a more recent contamination and don't prove anything.
I wasn't the only person in the United States who counted an extra reason to enjoy the parades and festivities this week. The announcement at CERN that two independent experimental groups had each collected convincing evidence that the long-sought Higgs particle had been found prompted the physicist and blogger Matthew Strassler to declare 4 July ‘IndependHiggs Day’. I couldn't imagine a better reason for fireworks.
One of the T-shirts you’ll see quite often around MIT says: ‘Speed limit: 186,000 miles per second. It’s not just a good idea. It’s the law.’ The speed in question is the speed of light, and the law comes from Albert Einstein’s theory of relativity. Relativity is predicated on the notion that the speed of light is unsurpassable, and most of modern physics is predicated on relativity. So this morning’s announcement that a team of physicists at CERN may have measured tiny particles, known as neutrinos, travelling faster than light has the potential to eclipse all other news that ever has or may yet come out of CERN – Higgs particles, supersymmetry and all else combined. The key word, though, is ‘potential’. By the physicists’ own reckoning, their results require a lot more scrutiny before anyone concludes that physics has one fewer leg to stand on.
David Kaiser · Antimatter
Last week a team of physicists based at CERN announced that they had coaxed a handful of elusive antihydrogen atoms into existence: 38 of them, to be exact. Simply creating antimatter is no longer newsworthy; a competing team fabricated tens of thousands of antihydrogen atoms using a different method back in 2002. What’s new about the latest experiment – the result of five years’ work – is that the fragile atoms stuck around for as long as 172 milliseconds: nearly one-fifth of a second, about half as long as the blink of an eye. And when it comes to atoms of antimatter, that is an astonishingly long time.
David Kaiser · The Large Hadron Collider
Fourteen years in the making, the Large Hadron Collider near Geneva spun to life in September 2008, sending the first batches of protons whirling around its 27-kilometre track at very nearly the speed of light. The goal was to smash the revved-up protons into each other at tremendous energies, mimicking conditions that would have been found moments after the big bang and unleashing new particles and interactions for physicists to scrutinise. The machine came screeching to a halt a few days later. One of the tanks holding liquid helium (to keep the superconducting magnets ultracold) had ruptured. No one could get close to the affected area to inspect the damage or begin repairs until the entire region had been taken off-line and ever-so-slowly warmed up. Fourteen months and £24 million later, the tank had been repaired, new equipment installed to bolster the LHC’s resistance to similar spikes in electrical current, and the entire machine cooled back down to its operating temperature.