How the starship keeps on trekking

Antimatter

十二月 8, 2000

Where would science fiction be without antimatter? Isaac Asimov's robots would remain lifeless, their brains deprived of antimatter stimulants, and the starship Enterprise would fail to boldly go where no man had gone before without antimatter to fuel it.

In spite of its place in science fiction, antimatter is rooted in fact. Every kind of particle has an antimatter partner - a particle identical in every respect except that it has an opposite electric charge. In his latest book, Gordon Fraser gives a clear and engaging account of the mirror-image world of antiparticles, from the first theoretical predictions in the 1920s to today's experiments at the cutting edge of particle physics. Antimatter was first predicted in the late 1920s by Paul Dirac, a brilliant young British physicist who was painfully shy and awkward. Dirac had a penetrating mathematical insight and was attempting to reconcile the two new theories of the age: quantum mechanics and Einstein's special relativity. His successful new equation predicted that electrons could also have negative energy - a finding that shocked the physics community. After a three-year struggle to understand the consequences of his equation, Dirac announced that the negative-energy electrons were a new type of particle with equal mass but a positive charge. Antimatter was born.

While Dirac was grappling with mathematical equations, Carl Anderson, a young American physicist, was studying the experimental tracks left by cosmic rays - high-energy particles that rain down from outer space. Among them, he found the telltale footprints of the positively charged electron, which became known as the positron.

Fraser describes the role that antimatter has played since the 1930s in physicists' quest to understand the building blocks of matter and the forces in nature. By using colourful metaphors rather than complex equations, he does an admirable job of explaining both the theoretical and experimental developments in the field.

With lively anecdotes and personal recollections, he brings alive the giants of 20th-century physics. Even particle physicists familiar with the science covered in Antimatter will enjoy Fraser's often touching and humourous accounts of the scientists who shaped the field. The only major criticism of the book is the sheer number of spelling mistakes.

Nevertheless, Fraser is an excellent storyteller who conveys the excitement and frustrations of research. Particularly memorable is his account of the discovery in 1995 of antihydrogen - the first atom synthesised purely from antimatter. The team that made the breakthrough at the Cern laboratory near Geneva consisted of just 16 physicists. They found just nine antihydrogen atoms, which soon made headline news all over the world. Indeed, the media's fascination with science and scientists is a theme that Fraser, who is editor of a monthly magazine for particle physicists, returns to.

Antiparticles are used in hospitals and have given neuroscientists new insights into the workings of the brain. Nevertheless, all the antiprotons produced in laboratories worldwide during one year would supply only enough energy to power a 100-watt light bulb for a few seconds, making warp speed nine very unlikely indeed.

Valerie Jamieson is features editor, Physics World , and a former particle physicist.

Antimatter: The Ultimate Mirror

Author - Gordon Fraser
ISBN - 0 521 65252 9
Publisher - Cambridge University Press
Price - £16.95
Pages - 213

请先注册再继续

为何要注册?

  • 注册是免费的,而且十分便捷
  • 注册成功后,您每月可免费阅读3篇文章
  • 订阅我们的邮件
注册
Please 登录 or 注册 to read this article.