Edward Witten - String theory

 Improbable Research/

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The search for the Higgs boson

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CERN announces sightings, but not proof, of possible Higgs boson signatures in the LHC, and our correspondents take a look inside the world's largest microscope

Stephen Hawking, "Equal to Anything!" [Excerpt]

 

Scientific American Physics/

A new not-so-brief history of Hawking: Kitty Ferguson's new biography of Stephen Hawking explores his life and ideas in depth. Image: Palgrave Macmillan/Gemma Levine

Editor's note: The following is an excerpt from the chapter "Equal to Anything!" from the new book Stephen Hawking: An Unfettered Mind (Palgrave Macmillan, 2012), by Kitty Ferguson.
 

When Stephen Hawking was twelve years old, two of his schoolmates made a bet about his future. John McClenahan bet that Stephen "would never come to anything"; Basil King, that he would "turn out to be unusually capable." The stake was a bag of candy. Young S. W. Hawking was no prodigy. Some reports claim he was brilliant in a haphazard way, but Hawking remembers that he was just another ordinary English schoolboy, slow learning to read, his handwriting the despair of his teachers. He ranked no more than halfway up in his school class, though he now says, in his defense, "It was a very bright class." Maybe someone might have predicted a career in science or engineering from the fact that Stephen was intensely interested in learning the secrets of how things such as clocks and radios work. He took them apart to find out, but he could seldom reassemble them. Stephen was never well-coordinated physically, not keen on sports or other physical activities, and almost always the last to be chosen for any sports team. John McClenahan had good reason to think he would win the wager.

Basil King probably was just being a loyal friend or liked betting on long shots. Maybe he did see things about Stephen that teachers, parents and Stephen himself couldn't see. He hasn't claimed his bag of sweets, but it's time he does. Because Stephen Hawking, after such an unexceptional beginning, is now one of the intellectual giants of our modern world—and among its most heroic figures. How such transformations happen is a mystery that biographical details alone cannot explain. Hawking would have it that he is still "just a child who has never grown up. I still keep asking these how and why questions. Occasionally I find an answer."

1942–1959
Stephen William Hawking was born during the Second World War, on January 8, 1942, in Oxford. It was a winter of discouragement and fear, not a happy time to be born. Hawking likes to recall that his birth was exactly three hundred years after the death of Galileo, who is called the father of modern science. But few people in January 1942 were thinking about Galileo.

Stephen's parents, Frank and Isobel Hawking, were not wealthy. Frank's very prosperous Yorkshire grandfather had over-extended himself buying farm land and then gone bankrupt in the great agricultural depression of the early twentieth century. His resilient wife, Frank's grandmother and Stephen's great-grandmother, saved the family from complete ruin by opening a school in their home. Her ability and willingness to take this unusual step are evidence that reading and education must already have been a high priority in the family.

Isobel, Stephen's mother, was the second oldest of seven children. Her father was a family doctor in Glasgow. When Isobel was twelve, they moved to Devon.

It wasn't easy for either family to scrape together money to send a child to Oxford, but in both cases they did. Taking on a financial burden of this magnitude was especially unusual in the case of Isobel's parents, for few women went to university in the 1930s. Though Oxford had been admitting female students since 1878, it was only in 1920 that the university had begun granting degrees to women. Isobel's studies ranged over an unusually wide curriculum in a university where students tended to be much more specialized than in an American liberal arts college or university. She studied economics, politics and philosophy.

Stephen's father Frank was a meticulous, determined young man who kept a journal every day from the age of fourteen and would continue it all his life. He was at Oxford earlier than Isobel, studying medical science with a specialty in tropical medicine. When the Second World War broke out he was in East Africa doing field research, and he intrepidly found his way overland to take ship for England and volunteer for military service. He was assigned instead to medical research.  More >>

Happy Birthday Stephen Hawking: How has he survived so long?

CAMBRIDGE, England — British scientist Stephen Hawking has decoded some of the most puzzling mysteries of the universe but he has left one mystery unsolved: How he has managed to survive so long with such a crippling disease.

The physicist and cosmologist was diagnosed with Lou Gehrig's disease when he was a 21-year-old student at Cambridge University. Most people die within a few years of the diagnosis, called motor neurone disease in the U.K. On Sunday, Hawking will turn 70.

"I don't know of anyone who's survived this long," said Ammar Al-Chalabi, director of the Motor Neurone Disease Care and Research Centre at King's College London. He does not treat Hawking and described his longevity as "extraordinary."

"It is unusual for (motor neurone disease) patients to survive for decades, but not unheard of," said Dr. Rup Tandan, a neurology professor at the University of Vermont College of Medicine. Still, Tandan said many longtime survivors had ventilators to breathe for them — which Hawking does not.

Hawking first gained attention with his 1988 book "A Brief History of Time," a simplified overview of the universe. It sold more than 10 million copies worldwide. His subsequent theories have revolutionized modern understanding of concepts like black holes and the Big Bang theory of how the universe began.

To mark his birthday Sunday, Cambridge University is holding a public symposium on "The State of the Universe," featuring talks from 27 leading scientists, including Hawking himself. For 30 years, he held a mathematics post at the university previously held by Sir Isaac Newton. Hawking retired from that position in 2009 and is now director of research at the university's Centre for Theoretical Cosmology.

Hawking achieved all that despite being nearly entirely paralyzed and in a wheelchair since 1970. He now communicates only by twitching his right cheek. Since catching pneumonia in 1985, Hawking has needed around-the-clock care and relies on a computer and voice synthesizer to speak.

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Tantalizing Hints of Elusive Higgs Particle Announced

Scientific American/ By Davide Castelvecch

 

TRACKING THE HIGGS: A reconstructed particle collision in the CMS detector of the LHC. Image: CMS/CERN

GENEVA—The two largest collaborations of physicists in history Tuesday presented intriguing but tentative clues to the existence of the Higgs boson, the elementary particle thought to endow ordinary matter with mass.

Representing the 6,000 physicists who work on two separate detectors at the Large Hadron Collider (LHC), called CMS and ATLAS, two spokespersons said that both experiments seemed to agree, as both their data sets suggested that the Higgs has a mass close to that of about 125 hydrogen atoms. The LHC is an international facility hosted by CERN, the European particle physics laboratory outside Geneva.

"We are talking of intriguing, tantalizing hints," said CMS spokesperson Guido Tonelli, speaking to a room filled with dozens of journalists and TV crews. "It's not evidence."

The experiments, in which protons traveling at nearly the speed of light collide head-on, cannot directly detect the Higgs, because the boson would decay within a fraction of a nanosecond into other particles. Instead, physicists must search through the debris of many different types of particle decay to find precise combinations of by-products that the Higgs would produce—and different chains of particle decays may well have the same signatures. A particular combination that appears more often than expected from other, "background" processes may signal the presence of the Higgs. But if it does not appear often enough compared with the expected background, it could just be a statistical fluctuation. Today, neither CMS nor ATLAS could claim to have the "3-sigma" statistical significance needed to claim evidence for a new particle—let alone 5 sigma for the accepted standard to claim a discovery. (A 3-sigma result implies a fraction of a 1 percent chance of a statistical fluke.) Instead, so far each experiment could only claim a statistical significance of around 2 sigma.

Both the detectors and the LHC accelerator itself, however, have been performing better than expected; so all the ducks are now in a row for settling the question soon, according to the researchers. "The nice thing to know is that by the end of 2012—sooner if we are lucky—we should be able to say the final word," Fabiola Gianotti, the ATLAS spokesperson, said at the press conference.

"I find it fantastic that we have the first results on the search for the Higgs, but keep in mind that these are preliminary results. And keep in mind that we have small numbers," said CERN Director General Rolf-Dieter Heuer in summarizing presentations that both Tonelli and Gianotti gave during a CERN seminar earlier that day.

"I think the evidence is very encouraging, though it's still too early to be sure," comments Steven Weinberg, a leading theoretical physicist at the University of Texas at Austin and a winner of the Nobel Prize in Physics.  More >>

Scientists close in on linchpin of physics, the ‘God particle’

The Washington Post/ Brian Vastag and Joel Achenbach

If rumors were dollars, the arcane world of particle physics would have enough cash to solve the Euro crisis.
For weeks, statements circulating on physics blogs have hinted at the discovery of an elusive particle essential to our understanding of how the universe works.

Called the Higgs boson, this particle — if spotted — would all but complete the fundamental theory of particle physics, known as the Standard Model. Confirmation of the Higgs would solve the mystery of why matter has the property that physicists call mass — the resistance to being shoved around.

If the Higgs does not exist, there’s a gaping hole in physicists’ explanation of nature’s deepest structure.

To search for this cosmic linchpin, the European Organization for Nuclear Research (CERN) built the biggest machine on Earth, a $10 billion circular tunnel some 17 miles long underneath the French-Swiss border called the Large Hadron Collider. Inside it, scientists smash together subatomic particles at astounding speeds. Sifting the debris offers clues as to whether the Higgs exists and what, exactly, it might look like.

On Tuesday, CERN scientists will unveil the latest results from two teams racing to spot the elusive quarry.

These new results are “sufficient to make significant progress in the search for the Higgs boson, but not enough to make any conclusive statement on the existence or non-existence of the Higgs,” read a CERN statement announcing a news conference Tuesday.

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Einstein: His Life and Universe

What's new on the fusion front?

By Alan Boyle

The standard joke about nuclear fusion is that it's the energy technology of the future, and always will be. Well, fusion is still an energy option for the future rather than the present, but small steps forward are being reported on several fronts. That even includes the long-ridiculed campaign for "cold fusion."

Efforts by the Italian-based Leonardo Corp. to harness low-energy nuclear reactions (the technology formerly known as cold fusion) have reawakened the dream of somehow producing surplus heat through unorthodox chemistry. Today, Pure Energy Systems News reported that Leonardo's Andrea Rossi signed an agreement with Texas-based National Instruments to build instrumentation for E-Cat cold-fusion reactors.

Will this venture actually pan out? The E-Cat reactors are so shrouded in secrecy and murky claims that it's hard to do a reality check, but most outside experts say that the concept just won't work.

Some observers are similarly pessimistic about the other avenues for fusion research. The basic physics of the reaction is well-accepted, of course. You can see the power generated when hydrogen atoms fuse into helium when you look at that big ball of gas in the sky, 93 million miles away, or when you watch footage of an H-bomb blast.

But no one has been able to achieve a self-sustaining, energy-producing fusion reaction in a controlled setting on Earth, even after more than a half-century of trying.

 

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Particles Found to Travel Faster than Speed of Light

By Geoff Brumfiel and Nature magazine

 

Image: CERN

An Italian experiment has unveiled evidence that fundamental particles known as neutrinos can travel faster than light. Other researchers are cautious about the result, but if it stands further scrutiny, the finding would overturn the most fundamental rule of modern physics—that nothing travels faster than 299,792,458 meters per second.

The experiment is called OPERA (Oscillation Project with Emulsion-tRacking Apparatus), and lies 1,400 meters underground in the Gran Sasso National Laboratory in Italy. It is designed to study a beam of neutrinos coming from CERN, Europe's premier high-energy physics laboratory located 730 kilometers away near Geneva, Switzerland. Neutrinos are fundamental particles that are electrically neutral, rarely interact with other matter, and have a vanishingly small mass. But they are all around us—the sun produces so many neutrinos as a by-product of nuclear reactions that many billions pass through your eye every second. [Click here to read more about CERN's Large Hadron Collider]

The 1,800-tonne OPERA detector is a complex array of electronics and photographic emulsion plates, but the new result is simple—the neutrinos are arriving 60 nanoseconds faster than the speed of light allows. "We are shocked," says Antonio Ereditato, a physicist at the University of Bern in Switzerland and OPERA's spokesman.

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