科学与翻译

Stephen Hawking has said that there is a 50-50 chance that we will find a complete unified theory in the next 20 years. Do you agree that the end of theoretical physics is in sight?

The most common criticism was equating the discovery of a theory that unified the four fundamental forces of nature - a so-called theory of everything - with the end of theoretical physics. Some theoretical particle physicists agreed with Hawking’s prediction about the chances of discovering a theory of everything, although several reckoned that it would take 50 to 100 years. Steven Weinberg, for example, said: “20 years is possible, but unlikely. I would guess 100 years for a ‘complete unified theory’. But a ‘complete unified theory’ would not be the end of theoretical physics.”

Kaku agreed that 20 years will be enough “to prove whether superstring theory is the theory of everything or the theory of nothing - there is no middle path. But even then, knowing the rules of chess does not mean we have become grand masters of chess. Similarly, knowing the rules of the unified field theory does not mean we have become grand masters of that theory. It may take us centuries before we exhaust the full implications and applications of a theory of everything”.

Gerard ‘t Hooft, however, was less optimistic about even the more limited interpretation of Hawking’s statement: “Absolutely not. He has been saying the same thing for more than 20 years. Physicists like him will say this again and again, always projecting the ultimate solution 20 years to the future. Although I do believe an ultimate theory is conceivable, we are many generations away from it.”

“Physics is not like getting to the top of Everest,” said Luciano Maiani, director general of CERN. “It is more like trying to get to absolute-zero temperature. As you get closer, new scales of phenomena appear and these call for a new effort and new understanding.”

Eugene Parker at Chicago was not convinced either. “The idea that when the last field equation is written down on paper, physics will come to an end is naive in the extreme,” he said. “In 1865, for example, Maxwell completed the electromagnetic field equations by adding the displacement current to Ampère’s law. That was the beginning of electromagnetism, not the end. When Schrödinger and then Dirac wrote down the quantum-mechanical wave equation, that was the beginning of quantum mechanics, not the end. When Einstein wrote down the equations of general relativity, that was the beginning of modern gravitational theory and cosmology, not the end.”

Many respondents pointed out that the discovery of a theory of everything will have little impact on the rest of physics “A unified theory would be a tremendous breakthrough,” said astronomer Alex Filipenko at the University of California at Berkeley, “but it would not, for example, lead to solutions of many important problems in condensed-matter physics, biophysics, astrophysics, and so on. It certainly won’t give us a much clearer picture of the origin of life or of intelligence. Much will remain to be done!”
摘自：http://physicsworld.com/cws/article/print/851

In October 1841 the 17-year-old Thomson entered St Peter’s College (Peterhouse), Cambridge, as a “pensioner” ­ in other words as a student who paid his own way. The formal tutoring in mathematics in his first year was of a very low level compared with what Thomson already knew. Indeed, by the time he reached Cambridge, Thomson had already published a paper in the Cambridge Mathematical Journal, in which he defended the mathematical rigour of Fourier series against the erroneous criticisms of Philip Kelland, a mathematician at Edinburgh University. During his time as an undergraduate he wrote a further 10 papers and was quickly tipped to be the “senior wrangler” (the student who would come first in the final mathematics examinations).

While Thomson was at Cambridge every member of his family regularly wrote to him. His father, who was footing all the bills, often advised him on the wise use of money and time. Yearly college maintenance fees alone came to £230, which would probably have accounted for as much as one-third of his father’s annual income. Thomson’s letters to his father often contained detailed lists of all expenditure. If writing to ask for extra money, he would sometimes include a mathematical theorem for possible use in exams to soften his father up.

In one early letter to his father, Thomson outlined how he planned to spend his days at Cambridge. His intention was to rise at 5 a.m. and light his fire; read until 8:15 a.m.; attend his daily lecture; read until 1 p.m.; exercise until 4 p.m.; attend chapel until 7 p.m.; read until 8:30 p.m.; and finally go to bed at 9 p.m. As Thomson’s modern biographers point out, it is doubtful whether he actually adhered strictly to this timetable, but it does illustrate his lifelong desire to minimize wasted time.

Thomson took part in many other activities at Cambridge besides studying. He rowed, becoming an excellent oarsman. He played the cornet and helped to establish the university’s music society. He also walked, skated and swam. Of all these activities it was Thomson’s rowing that his father disapproved of the most, fearing that it would bring his son into loose company, which would “ruin [Thomson] forever” with wine parties and time wasting.

Thomson’s final exams ­- the Senate House examinations ­- began on New Year’s Day 1845 and went on until 7 January. There were 12 papers, with morning papers lasting two and a half hours and afternoon papers three hours. The final result depended on both the quantity and quality of the answers to the questions. The exams were the toughest mathematical racecourse in the land, with the competitors trained like thoroughbreds to answer questions at top speed, and to use all possible short cuts to reach the answers.

To universal surprise Thomson came not first but second, behind one Stephen Parkinson of St John’s College. The family was disappointed, but justice was eventually done when Thomson came first in the Smith’s prize examination at the end of January. The papers for this exam were more suited to Thomson’s abilities, containing as they did more problem-solving questions and less of the bookwork that characterized the Senate House papers. Even though Thomson had come second in the Senate House examinations, the comments around Cambridge showed that he was by far the greater mind. As one examiner commented to a colleague: “You and I are just about fit to mend [Thomson’s] pens.” These successes meant that Thomson was elected a fellow of St Peter’s in June 1845 at the age of 21.

摘自：http://physicsworld.com/cws/article/print/16484