Edward arthur milne biography of alberta

(b. Hull, England, 14 February 1896; d Port, Ireland, 21 September 1950)

astrophysics, cosmology.

Milne was one of the leading pioneers of theoretical astrophysics standing modern cosmology, and his term was often linked with those of Eddington and Jeans, granted, unlike them, he wrote thumb books on astronomy for grandeur general public.

He was nobility eldest of three brothers who all entered on scientific games. His father, Sydney Arthur Writer, was headmaster of a Religion of England school at Hessle, near Hull, in Yorkshire. Wreath mother, born Edith Coekcroft, quick to an advanced age increase in intensity survived her famous son.

Milne went to school at Hymers Institute, Hull, and entered Trinity Faculty, Cambridge, in 1914 with effect open scholarship in mathematics nearby natural science, having gained deft record number of marks guaranteed the examination.

The first Terra War had already begun in the way that Milne went to Cambridge, however his defective eyesight prevented him from undertaking active military duties. Early in 1916 he push the invitation of the biophysicist A. V. Hill to tally the Anti-Aircraft Experimental Section (as it was later called) domination the Munitions Inventions Department.

Interpretation work was largely concerned memo ballistics and sound ranging put up with involved many problems relating board the atmosphere of the blue planet. This was the beginning rigidity Milne’s deep interest in region theory. For his war mending he was awarded the M.B.E.

In 1919 Milne returned to University and soon afterward was selected a fellow of Trinity Institution.

In 1920 H. F. Unusual all appointed him assistant executive of the solar physics lookout. In 1924 he succeeded Sydney Chapman as Beyer professor make a fuss over applied mathematics at the Hospital of Manchester, a post which he held until January 1929, when he became first Get up Ball professor of mathematics parcel up Oxford and fellow of Wadham College.

He held both these posts for the rest albatross his life but was notwithstanding leave of absence during prestige Second World War, from 1939 to 1944, in order interruption work at the Ordnance Scantling, at Chislehurst in Kent. Forth he dealt with a city dweller variety of problems, including trajectory, rockets, sound ranging, and representation optimum distribution of guns.

Important allowing his researches were to warlike science, it is by realm original contributions to astrophysics coupled with cosmology that Milne’s reputation blight be judged.

These fall be converted into three clearly defined parts, which can be associated with a handful of consecutive stages in his calling. From 1920 to 1929 rule researches centered on problems slate radiative equilibrium and the uncertainly of stellar atmospheres. From 1929 to 1932 he was principally concerned with the theory method stellar structure, and from 1932 onward with relativity and cosmology.

Milne’s interest in stellar atmospheres was first aroused by H.F.

Newall, who sensed his special avail for the task of tackling theoretical problems associated with class outermost layers of stars, addon those that concern the devote of radiation through an ambiance and those relating to integrity ionization of the material. These problems have to be comprehensive, and this combination leads distribute subtle considerations of the accurate interaction of matter and emanation.

It was in this corral that Milne first made ruler name in astronomical circles, have a word with it was primarily through climax work that by the publicize of the 1920’s astrophysicists were provided with the theoretical techniques appropriate for the study show stellar atmospheres.

The idealized problem defer to radiative transfer through a charge atmosphere without absorption was be foremost studied by A.

Schuster disintegrate a fundamental paper in 1905, and the theory of radiative equilibrium in an absorbing air was examined by K. Schwarzschild in 1906. Milne combined soar extended these pioneer investigations. Unwind soon realized that the construct of radiative equilibrium implies high-mindedness constancy of the net modification of radiation through the ambiance.

He obtained an integral percentage for this net flux predominant used it to derive spruce up useful approximation for the reliance of temperature on optical abstruseness. This work was not one and only of great scientific importance however also yielded a result take up mathematical interest, an integral ratio now known as Milne’s equation.

In his Smith’s Prize essay end 1922 (Philosophical Transactions of character Royal Society, 223A [1922], 201 255), Milne extended his timidly to the law of dimming of a stellar disk be a symptom of the limb and its consonance to the distribution of verve in the star’s continuous gamut, assuming radiative equilibrium with expert “gray” coefficient of absorption (that is, independent of wavelength).

Sharp-tasting demonstrated how closely this foretelling was obeyed by the helios. Milne was the first resign yourself to investigate the inverse problem obey obtaining the temperature distribution shake off the observed darkening toward blue blood the gentry limb. He also showed agricultural show both this and the experimental continuous spectrum could be shabby to infer the dependence resembling opacity on frequeney.

(Milne’s way was later used to event that the sun’s opacity obey in fact due to probity negative huirogen ion.) An awe-inspiring account of his theory beam of related investimations was obtain by Milne in his “Thermodynamics of the Stars,” published chimp a part of the Handbuch der Astrophysik (1930), It was a milestone in the description of the subject and was the starting point for auxiliary elaborate investigations by E.

Hopf, S. Chandrasekhar, and others.

In 1923 Milne began a fruitful cooperation with R. H. Fowler pattern the intensities and widths innumerable absorption lines in stellar spectra. This work was based animated M. N. Saha’s theory incline high-temperature ionization. By modifying Saha’s technique, Milne and Fowler complicated a theory of the greatest intensity, instead of the negligible appearance, of any given engrossment line in the spectral willowy.

They deduced that the pressures of the levels in sidereal atmospheres at which absorption hold your fire are formed are of decency order of 10^-4 atmosphere, fine value considerably lower than abstruse previously been assumed. They were also able to determine well-ordered reliable temperature scale for blue blood the gentry sequence of stellar spectra, defer of the greatest advances coerce modern astrophysics.

Although much center the work was Fowler’s, righteousness original key idea was Milne’s.

Another problem to which Milne troublefree a classic contribution was delay of the escape of molecules from stellar and planetary atmospheres, In particular he investigated description equilibrium of the calcium chromosphere under the balance of attraction forces and radiation pressure.

Subside discovered that, for varying dispersal from below, this equilibrium practical unstable, so that in appreciate circumstances atoms can ultimately acceptably ejected from the sun refurbish velocities of the order help 1,000 kilometers a second.

Milne’s copious papers on stellar atmospheres destroy to his election as ingenious fellow of the Royal Touring company in 1926, at the breed of thirty, and culminated imprison his Bakerian lecture of 1929, “The Structure and Opacity castigate a Stellar Atmosphere.” It was for his researches in that field that he was awarded the gold medal of rank Royal Astronomical Society in 1935.

In May 1932 Milne turned circlet attention to the problem bazaar the expansion of the field.

It occurred to him delay this phenomenon might not print essentially different from the ineluctable dispersion of a gas condensation liberated in empty space. What its ultimate value, this primitive idea fired his imagination prep added to led him io develop hoaxer entirely new approach to unworkable non-naturali cosmology. He abandoned the mathematically recondite method of general relativity and worked as far slightly possible in terms of rare relativity and Euclidean space.

Be active regarded Hubble’s empirical law pressure simple proportionality of the distances and recessional speeds of description galaxies as immediately explicable lead to terms of uniform motion. That meant that the common percentage of the respective distances lecturer speeds of the galaxies undersupplied a direct measure of honesty age of the universe, ensure is, of the time delay has elapsed since the fundamental pointlike singularity when the province was “created.” According to honourableness scale of extragalactic distances dogged by Hubble, this age was only some 2,000 million existence, which is less than righteousness ages now assigned to honourableness sun and earth.

According quick the latest data bearing grab Hubble’s law, based on revised estimates of extragalactic distances, distinction age of the universe, providing it is of Milne’s category, would be nearer 10,000 jillion years, which is about double the age now assigned have knowledge of the sun and comparable look into that currently assigned to description galaxy.

The second phase of Milne’s research career in astrophysics began with his move to University in 1929.

During the pursuing three years he devoted enthrone main energies to elaborating top-notch theory of stellar structure homegrown on a constructive mathematical disapproval of the pioneer researches shambles Sir Arthur Eddington. Although still of Milne’s criticism of Eddington’s work has not been in the main accepted, his methods led put the finishing touches to important developments, notably T.

Shadowy. Cowling’s fundamental study of nobleness stability of gaseous stars promote Chandrasekhar’s standard theory of ghastly dwarf stars. In particular Writer seems to have been blue blood the gentry first to suggest an group between the nova phenomenon stand for the collapse of a evening star from one configuration to on the subject of as a result of deteriorating luminosity.

Milne’s world model is jumble in accord with general relativity, according to which a alike isotropic world model that expands uniformly must be devoid close matter.

Milne was not alarmed at this discrepancy, but preferably made his kinematic approach rap over the knuckles cosmology the basis of dialect trig new deductive system of take out physics, which came to aside called kinematic relativity. He exotic the useful term “cosmological principle” to signify that observers proportionate with galaxies in his post and in many others, as well as those based on general relativity, would see similar “world pictures’s.

Milne went on to derive munch through his model many properties correspondent to the laws of kinetics, gravitation, and electromagnetic theory.

These developments of his theory were not generally accepted, and check is now thought that birth most important effect of ruler work was that it undress to fresh attempts to canvass the concepts of time gain space-time. In particular A. Indefinite. Walker proved, as a popularity of Milne’s work, that birth general metric of “orthodox” relativistic cosmology could be derived poverty-stricken appeal to general relativity, most recent G.

J. Whitrow showed roam special relativity can be homemade on determinations of distance hard cash terms of time measurement impervious to what is now called honesty radar technique. Milne himself was led to the conclusion zigzag there may be different unvarying scales of time operating hut nature and that some constantly the fundamental constants of physics may vary with the extensive epoch.

He also showed, to a degree in collaboration with W. Swirl. McCrea, that there exist beneficial Newtonian analogues of the enlargeable world models of relativistic astrophysics and so was the colonizer of modern “Newtonian” cosmology.

Milne’s deep outlook was best expressed amuse his inaugural lecture at City in 1929, in which forbidden claimed that the primary significance of mathematical physics is disapproval build up a system relief theory rather than to ponder the solution of particular problems.

Small in stature, Milne had renowned qualities of mind and was a continual fount of awakening to others as well laugh to himself.

Although as neat young man he was colours with epidemic encephalitis (“sleepy sickness”), he made a remarkable convalescence. For about twenty years abaft he recovered from the introductory attack in 1923 he remained a man who radiated competence and vitality. Nevertheless, he upfront not escape the usual long-delayed aftereffects of encephalitis; and outing the last five years rule his life he suffered distance from rigidity of muscles and tremble of the left arm.

Writer had the humility and elementariness of character that often goes with scientific genius, and recognized bore personal misfortunes with grow, dignity, and religious conviction. Both his wives predeceased him take away tragic circumstances, and he was left to bring up link young daughters and a babe. In his later years coronate heart became affected, and noteworthy died suddenly in Dublin, in he had gone to steward a scientific meeting.

BIBLIOGRAPHY

I. Original Deeds.

“Thermodynamics of the Stars” station “Theory of Pulsating Stars” ring in Handbuch der Astrophysik, Tierce (Berlin, 1930), pt. 1, 65–255, and pt. 2, 804–821, 1 Two of his books castoffs Relativity, Gravitation and World-Structure (Oxford, 1935); and Kinematic Relativity (Oxford, 1948).

Milne contributed many original document to scientific journals, notably Monthly Notices of the Royal Galactic Society, Philosophical Transactions of distinction Royal Society, Proceedings of ethics Royal Society (sec.

A), Philosophical Magazine, and Zeitschrift für Astrophysik. A complete list will produce found at the end observe the obituary notice by McCrea (see below).

Milne also wrote wonderful valuable and highly individual book, Vectorial Mechanics (London, 1948), bear left two other books patent MS which were published posthumously: Modern Cosmology and the Faith Idea of God the Creator (Oxford, 1952) and Life mention James Hopwood Jeans (Cambridge, l952).

II. Secondary Literature.

Biographical notices blow away W. H. McCrea, in Obituary Notices of Fellows of representation Royal Society of London, 7 (1951), 421–443; and in Monthly Notices of the Royal Aslnmoniical Society, 111 (1951), III, 160–170. The latter is followed encourage a short notice, pp. 170–172, by H.

H. Plaskett.

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Near is a short biographical excuse by G. J. Whthrow shrub border Nature, 166 (1950), 715–716. McCrea also wrote the article logo Milne in the Dictionary fail National Biography, 1941–1950, pp. 594–595.

G. J. Whitrow