爱德华·亚瑟·米尔恩Edward Arthur Milne

爱德华·亚瑟·米尔恩出生在赫尔，他的父亲Sidney Milne是英格兰教会学校的校长。他的母亲Edith Cockcroft也是一名教师。米尔恩是他父母三个孩子中的老大，都是男孩，都成为了科学家。当米尔恩九岁时，全家搬到了赫尔附近的Hessle。在此之前，他一直在他父亲的学校上学。

米尔恩在赫尔的Hymers学院（一所捐赠学校）接受中学教育，并从那里获得了数学和自然科学开放奖学金，在剑桥大学三一学院学习。这是一项非凡的成就，因为他不仅在1914年赢得了这项奖学金，还获得了考试中有史以来授予的最高分数。在剑桥，在他学习的十八个月里，他受到了西德尼·查普曼和戈弗雷·哈罗德·哈代的启发。

米尔恩视力不佳，无法在第一次世界大战中服役。然而，1916年他加入了一个防空部门从事弹道学工作的团队。Meg Weston Smith在[11]中写道：-

1916年，他放弃学业，加入了一个创新研究团队，研究炮弹、引信等的性能。除了提供相关的数学知识外，他还乘坐早期飞机飞行，悬挂在机翼上读取温度和压力数据，并指导著名统计学家卡尔·皮尔逊根据团队的发现制定新的射击表，这些射击表在整个武装部队中分发。米尔恩还增进了对风和声音的理解，在此过程中改进了用于夜间探测飞机的大型双耳听音喇叭。在团队领导者A V Hill和拉尔夫·福勒（米尔恩后来与之合作）的指导下，米尔恩接受了如何进行研究的出色训练。因此，他在团队中度过的三年可能在他的教育中与他在剑桥的一年半同等重要。

1919年，米尔恩回到剑桥，但无意完成本科学位或攻读博士学位。回到剑桥后不久，米尔恩当选为三一学院研究员，并于1920年被任命为剑桥太阳物理天文台的助理主任。他在其主任H F Newell的指导下工作，后者建议他将注意力转向恒星大气的研究。

米尔恩关于恒星大气的工作扩展了Schuster在1905年和卡尔·史瓦西在1906年早些时候所做的工作。Schuster研究了辐射的传输，其中假设大气中没有发生吸收，而卡尔·史瓦西研究了吸收大气中辐射的平衡态。米尔恩结合了这两种方法，提出了一个具有重大数学意义的积分方程，现在被称为米尔恩积分方程。

1922年，米尔恩因一篇关于恒星圆面临边昏暗的论文获得剑桥史密斯奖。他计算了由恒星光谱中给定能量分布导致的临边昏暗程度，并将他的理论结果与太阳的已知值进行了比较。然后，他研究了从临边昏暗推断恒星光谱中能量分布的逆问题。我们上面提到米尔恩与拉尔夫·福勒合作；他们在1923年合作研究了恒星光谱中的吸收线。

西德尼·查普曼于1924年辞去曼彻斯特大学Beyer应用数学教授职位，以就任伦敦帝国理工学院数学讲席。米尔恩被任命接替西德尼·查普曼担任曼彻斯特大学Beyer应用数学教授，于1925年就职。在曼彻斯特期间，他继续研究辐射平衡和恒星大气结构，他在这些主题上的工作使他当选为皇家学会会士。1928年，他接受了牛津大学Rouse Ball讲席，并于1929年1月就职，成为首位持有者。他1929年关于The Structure and Opacity of a Stellar Atmosphere的皇家学会贝克讲座标志着他对该主题研究的结束。

1928年，米尔恩与Margaret Campbell结婚。他们有两个女儿和一个儿子，但不幸的是，他的妻子在儿子出生时去世。他于1940年再婚，这次是与来自纽约的Beatrice Brevoort Renwick结婚。这第二次婚姻生了一个女儿，但遗憾的是，他的妻子在结婚五年后去世。

大约从米尔恩担任牛津大学Rouse Ball讲席教授时起，他转向了另一个研究课题，这次是研究恒星的结构。他关于这一课题的工作主旨是提出与亚瑟·爱丁顿不同的观点。Whitrow在[1]中写道：-

尽管米尔恩对亚瑟·爱丁顿工作的许多批评并未被普遍接受，但他的方法导致了重要的发展……

在专注于恒星结构的数学理论约三年后，米尔恩将注意力转向了宇宙学。他发展了一种称为运动学相对论的新相对论形式，作为阿尔伯特·爱因斯坦广义相对论的替代方案，这也遭到了相当大的反对。然而，他的工作使人们重新思考旧观念，并导致了空间和时间基本概念的新方法。

米尔恩的著作包括Thermodynamics of the Stars（1930年），其中包含与上述他的史密斯奖论文相关的材料，Relativity, Gravitation and World-Structure（1935年）和Kinematic Relativity（1948年）。这些都是为他的学术同行撰写的学术文本，与他同时代的大多数其他著名天文学家不同，他没有撰写面向普通公众的文本。

米尔恩在其职业生涯中获得了许多荣誉。他于1926年当选为皇家学会会士，并于1929年应邀作贝克讲座。1941年，米尔恩被授予皇家学会皇家奖章：-

……因其对地球和太阳大气、恒星内部结构以及相对论的研究。

他于1943年至1945年担任皇家天文学会主席，此前已于1935年获得该学会金质奖章。

米尔恩作为讲师和作者的能力与风格在[2]中有所描述：-

他特别具有清晰表达的天赋，无论是口头还是书面，看他自信地一步步穿过复杂论证的各个环节，既令人兴致盎然又令人受益匪浅。但与他的广阔视野相辅相成的是他对细节的强烈兴趣，这有时会让听众看不清他阐述的主线。

关于米尔恩的品格，Whitrow在[1]中写道：-

身材矮小的米尔恩具有杰出的心智品质，对他自己和他人都是源源不断的灵感之源。……米尔恩具有科学天才常有的谦逊和质朴性格，他以勇气、尊严和宗教信念承受个人的不幸。

在[2]中他被描述为：-

……非常有人情味，分享家庭和家人的欢乐、用餐的欢乐以及社交礼仪的欢乐。他的幸福在很大程度上取决于科学界同仁的善意和认可；尽管他才华出众、成就斐然，但在抑郁的时刻，他仍因自感不足而备受折磨。

年轻时米尔恩曾患昏睡性脑炎。这是一种炎症，在第一次世界大战后作为一种流行病席卷欧洲。I. Milne于1924年感染此病，到1925年已恢复良好。通常与该病相关的是帕金森型症状，这些症状在晚年出现，米尔恩也是如此，其后遗症大约在1945年出现。同年他遭遇了另一场悲剧，他的第二任妻子比阿特丽斯去世。米尔恩在都柏林参加皇家天文学会会议时因心脏病发作去世。

E A Milne was born in Hull where his father, Sidney Milne, was the headmaster of a Church of England school. His mother, Edith Cockcroft, was also a teacher. Arthur was the oldest of his parents' three children, all boys, all of whom became scientists. The family moved to Hessle, near Hull, when Arthur was nine years old. Before this he had been attending his father's school.

Milne attended Hymers College (an endowed school) in Hull for his secondary schooling and from there he won an open scholarship in mathematics and natural science to study at Trinity College, Cambridge. It was a remarkable achievement for not only did he win this scholarship in 1914, he gained the largest number of marks which had ever been awarded in the examination. At Cambridge, in the eighteen months during which he studied there, he was inspired by Chapman and Hardy.

Milne's defective eyesight prevented him from active service in World War I. However, in 1916 he joined a team working on ballistics at the Anti-Aircraft Section. Meg Weston Smith writes in [11]:-

In 1916 he abandoned his studies to join an innovative research team examining the behaviour of shells, fuses etc. Beyond producing the relevant mathematics, he flew in early aircraft, hanging over the wing to take readings of temperature and pressure, and he supervised the eminent statistician Karl Pearson in drawing up new firing tables, based on the team's findings, which were issued throughout the armed services. Milne also increased the understanding of wind and sound, in the course of refining the huge binaural listening trumpets which detected aircraft at night. Under the team's leader A V Hill, and R H Fowler (with whom Milne later collaborated) Milne received a marvellous training in how to do research. Thus his three years with the team probably ranked equally in importance in his education with his one and half year's at Cambridge.

In 1919 Milne returned to Cambridge but not with the intention of either completing his undergraduate degree or of studying for a doctorate. Elected a Fellow of Trinity College shortly after he came back to Cambridge, Milne was appointed assistant director of the Solar Physics Observatory in Cambridge in 1920. He worked there under its director H F Newell who suggested that he turn his attention to work on stellar atmospheres.

Milne's work on the atmospheres of stars extended work done earlier by Schuster in 1905 and by Schwarzschild in 1906. Schuster had studied the transfer of radiation where it was assumed that no absorption was taking place in the atmosphere, while Schwarzschild studied equilibrium states for radiation in an absorbing atmosphere. Milne combined the two approaches and came up with an integral equation of great mathematical interest which is now known as Milne's integral equation.

In 1922 Milne won a Smith's Prize at Cambridge for an essay on the darkening of the limb of a stellar disk. He calculated the amount of darkening of the limb resulting from a given energy distribution in the star's spectrum, and compared his theoretical results with the known values for the sun. He then studied the inverse problem of deducing the energy distribution in a star's spectrum from the limb darkening. We mentioned above that Milne collaborated with R H Fowler; they cooperated in 1923 in studying absorption lines in stellar spectra.

Sydney Chapman resigned as Beyer professor of applied mathematics at Manchester in 1924 in order to take up the chair of mathematics at Imperial College London. Milne was appointed to succeed Chapman as Beyer professor of applied mathematics at Manchester, taking up the post in 1925. While at Manchester he continued his research into radiative equilibrium and the structure of stellar atmospheres, and his work on these topics led to his election to a Fellowship of the Royal Society. In 1928 he accepted the Rouse Ball Chair at Oxford, becoming the first holder when he took up the appointment in January 1929. His Royal Society Bakerian lecture in 1929 on The Structure and Opacity of a Stellar Atmosphere marks the end of his research into this topic.

In 1928 Milne married Margaret Campbell. They had two daughters and one son, but tragically his wife died during the birth of the son. He married again in 1940, this time to Beatrice Brevoort Renwick from New York. This second marriage produced one daughter but sadly his wife died five years after the marriage.

From around the time that Milne took up the Rouse Ball Chair at Oxford, he moved on to another research topic, this time studying the structure of stars. The main thrust of his work on this topic was to give different ideas to those of Eddington. Whitrow writes in [1]:-

Although much of Milne's criticism of Eddington's work has not been generally accepted, his methods led to important developments ...

After about three years concentrating on a mathematical theory of stellar structure, Milne turned his attention to cosmology. He developed a new form of relativity called kinematic relativity, an alternative to Einstein's general theory of relativity, which also met with considerable opposition. However, his work made people rethink old ideas and led to new approaches to the fundamental concepts of space and time.

Milne's books include Thermodynamics of the Stars (1930) which contains material relating to his Smith's Prize essay discussed above, Relativity, Gravitation and World-Structure (1935), and Kinematic Relativity (1948). These were all scholarly texts written for his fellow academics and, unlike most of the other famous astronomers of his time, he wrote no texts intended for the general public.

Milne received many honours during his career. He was elected to the Royal Society in 1926 and invited to give its Bakerian lecture in 1929. In 1941 Milne was awarded the Royal Medal of the Royal Society:-

... for his researches on the atmosphere of the Earth and the sun, on the internal constitution of the stars, and on the theory of relativity.

He was President of the Royal Astronomical Society from 1943 to 1945 having been awarded the Society's gold medal in 1935.

Milne's abilities and style as a lecturer and author are described in [2]:-

He was notably gifted with the power of lucid expression in speech and writing, and it was highly interesting to see and hear him threading his way with surety through the steps of a complex argument. But complementary to his breadth of view was an intense interest in detail, which sometimes for his hearers obscured the main lines of his exposition.

As to Milne's character Whitrow writes in [1]:-

Small in stature, Milne had outstanding qualities of mind and was a continual fount of inspiration to others as well as himself. ... Milne had the humility and simplicity of character that often goes with scientific genius, and he bore personal misfortunes with courage, dignity, and religious conviction.

In [2] he is described as:-

... very human, sharing in the delights of home and family, of meals, and of social ceremony. His happiness depended greatly on the good will and approval of his scientific colleagues; in spite of his unmistakable brilliance and achievement, in moments of depression he was sorely tried by a sense of inadequacy.

As a young man Milne had suffered from encephalitis lethargica. This was a type of inflammation which swept across Europe in an epidemic after World War I. Milne contracted the disease in 1924, and had made a good recovery by 1925. Usually associated with the disease there are Parkinson type symptoms which appear later in life, and this was so with Milne, in whom the after-effects appeared around 1945. He suffered another tragedy in this same year when his second wife Beatrice died. Milne died from a heart attack in Dublin while attending a conference of the Royal Astronomical Society.