A victim of an incurable disease, Stephen Hawking is almost completely paralysed, confined to a wheelchair, and unable to speak. Yet, he has overcome every obstacle and achieved far more than most able-bodied people ever dream of accomplishing and become one of the greatest physicists of our time.
Roaming the Cosmos
Leon Jaroff
Darkness has fallen on Cambridge, England, and on a damp and chilly evening king's Parade is filled with students and faculty. Then, down the crowded thoroughfare comes the University of Cambridge's most distinctive vehicle, bearing its most distinguished citizen. In the motorized wheelchair, boyish face dimly illuminated by a glowing computer screen attached to the left armrest, is Stephen William Hawking, 46, one of the world's greatest theoretical physicists. As he skillfully maneuvers through the crowd, motorists slow down, some honking their horns in greeting. People wave and shout hello.
A huge smile lights up Hawking's bespectacled face, but he cannot wave or shout back. Since his early 20s, he has suffered from amyotrophic lateral sclerosis (ALS), a progressive deterioration of the central nervous system that usually causes death within three or four years. Hawking's illness has advanced more slowly, and now seems almost to have stabilized. Still, it has robbed him of virtually all movement. He has no control over most of his muscles, cannot dress or eat by himself and has lost his voice. Now he "speaks" only by using the slight voluntary movement left in his hands and fingers to operate his wheelchair's built-in computer and voice synthesizer.
While ALS has made Hawking a virtual prisoner in his own body, it has left his courage and humor intact, his intellect free to roam. And roam it does, from the infinitesimal to the infinite, from the subatomic realm to the far reaches of the universe. In the course of these mental expeditions, Hawking has conceived startling new theories about black holes and the disorderly events that immediately followed the Big Bang from which the universe sprang. More recently, he has shaken both physicists and theologians by suggesting that the universe has no boundaries, was not created and will not be destroyed.
Most of Stephen Hawking's innovative thinking occurs at Cambridge, where he is Lucasian professor of mathematics, a seat once occupied by Isaac Newton. There, in the Department of Mathematics and Theoretical Physics, he benevolently reigns over the relativity group, 15 overachieving graduate students from nine countries. On his office door is a small plaque irreverently reading QUIET, PLEASE. THE BOSS IS ASLEEP.
Hardly. From midmorning until he departs for dinner around 7 p. m., Hawking follows a routine that would tax the most able-bodied, working in his book-lined office, amid photographs of his wife Jane and their three children. When he rolled into the department's common room one morning last month, his students were talking shop around low tables. Maneuvering to one of the tables, Hawking clicked his control switch, evoking tiny beeps from his computer and selecting words from lists displayed on his screen. These words, assembled in sequence at the bottom of the screen, finally issued from the voice synthesizer: "Good morning. Can I have coffee?" Then, for the benefit of a visitor: "I am sorry about my American accent." (The synthesizer is produced by a California company.)
When the conversation shifted to creativity and how mathematicians seem to reach a creative peak in their early 20s, Hawking's computer beeped. "I'm over the hill," he said, to a chorus of laughter.
Hawking was born on Jan. 8, 1942-300 years to the day, he often notes, after the death of Galileo. As a small boy, he was slow to learn to read but liked to take things apart though he confesses that he was never very good at putting things back together. When he was twelve, he recalls humorously, "one of my friends bet another friend a bag of sweets that I would never come to anything. I don't know if this bet was ever settled and, if so, who won.
Fascinated by physics, Stephen concentrated in the subject at Oxford's University College, but did not distinguish himself. He partied, took a great interest in rowing and studied only an hour or so a day. Moving on to Cambridge for graduate work in relativity, he found the going rough, partly because of some puzzling physical problems; he stumbled frequently and seemed to be getting clumsy.
Doctors soon gave him the bad news: he had ALS, it would only get worse, and there was no cure. Hawking was overwhelmed. Before long, he needed a cane to walk, was drinking heavily and ignoring his studies. "There didn't seem to be much point in completing my Ph. D.," he says.
Then Hawking's luck turned. The progress of the disease slowed, and Einsteinian space-time suddenly seemed less formidable. But what really made the difference, he says, "was that I got engaged to Jane," who was studying modern languages at Cambridge. "This gave me something to live for." As he explains, "if we were to get married, I had to get a job. And to get a job, I had to finish my Ph. D. I started, working hard for the first time in my life. To my surprise, I found I liked it."
What particularly interested Stephen was singularities, strange beasts predicted by general relativity. Einstein's equations indicated that when a star several times larger than the sun exhausts its nuclear fuel and collapses, its matter crushes together at its center with such force that it forms a singularity, an infinitely dense point with no dimensions and irresistible gravity. A voluminous region surrounding the singularity becomes a "black hole," from which -- because of that immense gravity -- nothing, not even light, can escape.
Scientists years ago found compelling evidence that black holes exist, but they were uncomfortable with singularities, because all scientific laws break down at these points. Most physicists believed that in the real universe the object at the heart of a black hole would be small (but not dimensionless) and extremely dense (but not infinitely so). Enter Hawking. While still a graduate student, he and Mathematician Roger Penrose developed new techniques proving mathematically that if general relativity is correct, singularities must exist. Hawking went on to demonstrate - again if general relativity is correct - that the entire universe must have sprung from a singularity. As he wrote in his 1966 Ph. D. thesis, "There is a singularity in our past."
Stephen later discerned several new characteristics of black holes and demonstrated that the amazing forces of the Big Bang would have created mini-black holes, each with a mass about that of a terrestrial mountain, but no larger than the subatomic proton. Then, applying the quantum theory (which accurately describes the random, uncertain subatomic world) instead of general relativity (which, it turns out, falters in that tiny realm), Hawking was startled to find that the mini-black holes must emit particles and radiation. Even more remarkable, the little holes would gradually evaporate and, 10 billion years or so after their creation, explode with the energy or millions of H-bombs.
Hawking has visited the U. S. 30 times, made seven trips to Moscow, taken a round-the-word journey, and piloted his wheelchair on the Great Wall of China. On the road, the activities occasionally deviate somewhat from physics. One night Stephen accompanied a group to a Chicago discotheque, where he joined in the festivities by wheeling onto the dance floor and spinning his chair in circles.
Recently, Hawking, who has no qualms about recanting his own work if he decides he was wrong, may have transcended his famous proof that singularities exist. With Physicist James Hartle. He has derived a quantum wave describing a self-contained universe that, like the earth's surface, has no edge or boundary. If that is the case, says Hawking, Einstein's general theory of relativity would have to be modified, and there would be no singularities. "The universe would not be created, not be destroyed; it would simply be," he concludes, adding challengingly, "What place, then, for a Creator?"
斯蒂芬·霍金患了一种不治之症,几乎完全瘫痪,离不开轮椅,而且不能说话。然而,他克服了一切障碍,取得了比大多数体格健全者想要取得的还要多得多的成就,成了我们时代最伟大的物理学家之一。
遨游宇宙
利昂·贾洛夫
夜幕降临,暮色笼罩着英格兰剑桥市。在一个潮湿、寒冷的夜晚,“国王阅兵场”上到处是剑桥大学的师生。这时,沿着拥挤的大道驶来了校园内最有特色的一部车子,上面载着该校最著名的公民。在这辆机动轮椅上坐着的是世界上最伟大的理论物理学家之一,四十六岁的斯蒂芬·威廉·霍金。固定在轮椅左边靠手上的一只发光的计算机屏幕隐隐约约地照出了他那张孩子似的脸庞。当他熟练地驾着轮椅驶过人群时,开汽车的人都放慢车速,有的还揿揿喇叭向他致意。人们挥着手,大声跟他打招呼。
戴着眼镜的霍金满面闪露出笑容,但他既不能挥手,也不能回喊作答。他刚二十岁出头时就患了肌萎缩性脊髓侧索硬化症(ALS)。这是一种使中枢神经系统日益退化的病症,患者一般在三四年内就会死亡。霍金的病情发展较慢,目前看来几乎已经稳定。然而,这病仍使他失去了几乎所有的活动能力。他已经不能控制大部分肌肉,不能自己穿衣进食,不能开口说话。现在他只能依靠手和手指还剩下的一点随意运动的能力操纵装在轮椅上的计算机和声音合成器来“说话”了。
虽然ALS病症使霍金成了一个行动不便的残疾人,但他的勇气和幽默仍完整无损。他的智力仍在自由地漫游。他的智力也的确是在漫游,从无穷小漫游到无穷大,从亚原子王国漫游到宇宙的遥远区域。在这些智力探索的过程中,霍金已构想出一些有关黑洞以及紧接着形成宇宙的“大爆炸”而产生的种种纷乱活动的惊人的新理论。最近,他又提出了宇宙没有边际,它既不是创造出来的,将来也不会毁灭的看法,从而使物理学家和神学家们都大为震惊。
斯蒂芬·霍金的大部分创见是在剑桥大学形成的。他现在是该校的卢卡斯数学教授,这是艾萨克·牛顿曾经担任过的一个教职。在剑桥大学的数学和理论物理系,他仁慈地“统治”着相对论小组,组里有来自九个国家的十五名出类拔萃的研究生。他的办公室门上有一块小饰板,上面大不敬地写着:请安静,老板在睡觉。
没那回事儿。从上午九点到下午七点左右回家吃饭,霍金一直都在四壁排满书、面前摆着夫人简和三个孩子照片的办公室里工作,每日的工作量之大足以使身体最强壮的人也感到劳累不堪。上个月的某天上午,当他坐着轮椅来到系的师生公共休息室时,他的研究生正围着矮桌子在三句不离本行地交谈着。霍金熟练地操纵着轮椅来到一张桌子旁边,咔哒一声按了按控制开关,计算机便发出轻微的嘟嘟声。他从显示在屏幕上的词表中选出了几个单词,这些单词在屏幕下方按顺序排列好以后,终于从声音合成器中放了出来:“早上好。我可以来杯咖啡吗?”接着,为了在座的一位来访者,他又特意加了一句:“对不起,我的发音带有美国腔。”(他用的声音合成器是美国加州的一家公司制造的。)
当话题转到创造力以及数学家似乎在二十几岁就达到一个创造力的高峰时,霍金的计算机发出了嘟嘟声。他说:“我已经在走下坡路了。”一句话引得众人哈哈大笑。
霍金生于1942年1月8日,这一天——他常常提到——正好是伽利略逝世三百周年纪念日。小时候,他学习阅读很迟钝,但他喜欢把东西拆开,不过他承认自己从来不善于把拆开的东西再照原样装好。他幽默地回忆说,十二岁的时候,“我的一个朋友以一袋糖果跟另一个朋友打赌,说我永远不会有什么作为。我不知道这次打赌是不是已经了结,如果已经了结,也不知道是谁打赢了。”
斯蒂芬酷爱物理,曾在牛津大学的大学学院专攻这一学科,但成绩并不突出。他参加各种社交聚会,对划船特别感兴趣,每天只学习一个小时左右。进入剑桥大学作研究生攻读相对论时,斯蒂芬发觉学习很吃力。造成这一情况的部分原因是他身体内出现的一些莫名其妙的症状;他常常绊倒,而且手脚也似乎越来越不灵活了。
很快,医生便向他报告了坏消息:他患了ALS症。这种病只会恶化,而没有办法治愈。霍金悲伤之至。不久,他便需要拄着拐杖才能行走;他开始酗酒,置学习于不顾。他说:“在当时的情况下,完成博士学业似乎已没有多大意义了。”
后来,霍金时来运转。病情的发展慢了下来,而爱因斯坦的时空观也突然显得不那么令人生畏了。但真正对他产生了重大影响的,他说,“是我与简订了婚。”当时她正在剑桥大学攻读现代语言。“这使我有了一个生活目的。”正如他所解释的那样:“如果我们打算结婚,我就要找到一份工作。而要找到工作,我就得完成博士学位。于是我生平第一次开始刻苦学习了。出乎我的意料,我发觉我喜欢刻苦学习。”
使斯蒂芬特别感兴趣的是奇点。这是广义相对论所预言的一种怪物。爱因斯坦的方程式表明,当一个比太阳大数倍的星体耗尽了自身的核燃料而坍塌时,它的物质便以雷霆万钧之力在其核心部位挤在一起,从而形成一个奇点,这一奇点没有维度,却具有无限的密度和不可抗拒的引力。奇点周围的广大区域便成了一个“黑洞”,而由于那巨大的引力,任何东西都不能逃离黑洞,即使光也不能。
好多年以前,科学家们就发现了表明黑洞存在的有力证据,但对于奇点,他们都感到不安,因为在这些点上,所有的科学原理都失效了。大多数物理学家认为,在现实的宇宙中,黑洞中心的物体可能是微小的(但并非没有维度),其密度也会是极高的(但并非无限髙)。这时候,霍金上场了。还在当研究生的时候,他就和数学家罗杰·彭罗斯一起设计出一些新的方法,从数学上证明:如果广义相对论是正确的,那么奇点就一定存在。霍金接着还证明:如果广义相对论是正确的,那么整个宇宙一定是从一个奇点中产生出来的。正如他在1966年的博士论文中所写的那样:“在我们的过去有个奇点。”
后来斯蒂芬又发现了黑洞的一些新的特点,并且证明:“大爆炸”的巨大力量可能造成了一些小黑洞,每个微小黑洞的质量大约相当于地球上一座大山的质量,而体积不会大于亚原子质子。接着,霍金在应用量子论而不是广义相对论时——因为量子论精确地描述了那个不规则、不确定的亚原子世界,而广义相对论却在这个小小的领域中不起作用——惊奇地发现,那些微小黑洞一定在放射粒子与辐射线。更值得注意的是,那些微小黑洞竟会逐渐蒸发,并在它们形成后一百亿年左右发生爆炸,释放出相当于几百万颗氢弹的能量。
霍金曾三十次访问美国,七次访问莫斯科,作过一次环球旅行,还驾着轮椅游览了中国长城。在旅途中,他偶尔也参加一些与物理学并无多少关系的活动。一天晚上,他陪着一群人来到芝加哥的一家夜总会,在那儿他坐着轮椅进入舞池,驾着轮椅团团旋转,与大家一起欢乐。
一旦认定自己错了,霍金会毫不犹豫地放弃自己的成果。最近他也许已经超越了自己关于奇点存在的著名论证。他与物理学家詹姆斯·哈特尔合作,已经获得了一种描述独立宇宙的量子波,这一宇宙和地球表面一样,也是无边无际的。霍金说:如果情况果真如此,那么爱因斯坦的广义相对论就得修正,奇点也是子虚乌有的了。他推断说:“那样宇宙就不是创造出来的,也就不会被毁灭了;它只是一直存在着。”他又带着挑战的口吻补充了一句:“果真如此,哪里还有什么造物主呢?”
参考资料:
1. 大学英语精读第五册 Unit 8_大学教材听力 - 可可英语
2. 大学英语精读(第三版) 第五册: unit7A Roaming the Cosmos(1)_大学教材听力 - 可可英语