NOTED ASTRONOMERS

Taranaki Daily News, 21 October 1933, Page 1 (Supplement)

NOTED ASTRONOMERS

ANCIENT AND MODERN

(By

Rev. B. Dudley,

F.R.A.S.)

Any list of famous astronomers must run the risk of having a somewhat encyclopaedic appearance. But there are reasons for thinking that some readers would appreciate a portrait gallery of the kind. It is not possible to mention every honoured name. The selection here made of men who have contributed to the progress of astronomical science will, it is hoped, include such names as will vindicate the headlines. For purposes of reference they are presented in alphabetical order. John Couch Adams (born. 1819) concluded from his mathematical calculations that certain irregularities in the motion of Uranus were due to the attraction of an outer planet, of which he (1845) computed the possible orbit. These led to the discovery of Neptune. Al-Sufi was the Persian Astronomer who during the 10th century A.D. drew up a catalogue of over 1000 stars, which proved to be of exceptional value. Anaximander (611-547 8.C.) succeeded Thalefc in the Greek school of astronomy and discovered the obliquity of the ecliptic. Eugene Michael Antoniadi discovered the nebulosity around the new star, in the constellation Perseus at the beginning of the 20th century. He did outstanding work in delineating planets. Francois Jean Arago, bom in France in 1786, was director of the Paris Observatory in 1830, discovered the rotary motion of magnetism, established the connection between aurorae and magnetic variations and demonstrated the undulatory theory of light. Frederich Wilhelm Argelander (bom 1799) was the noted German who made a catalogue of some 300,000 stars visible in a small telescope. ■ These were all northern objects and the compilation is famous under the name of the “Bonn Durchmusterung.” Svante Arrhenius, a Swedish astronomer, wrote “Worlds in the Making,” dealt with the problems of radiation and light pressure, and held the theory that the appearance of “new stars” is due to the collision of suns.

Sir Robert Ball did much to popularise the study of astronomy. He was Lowndean Professor, and director of the Cambridge Observatory for many years, being appointed in 1892. He met. with eminent success as a writer and lecturer. Dr. Edward E. Barnard, Professor of Astronomy at Yerkes Observatory, distinguished himself as an observer of double stars. He also found a sth satellite of Jupiter (1892) and was first to discover a comet by means of the camera and to photograph star cipuds in the Milky Way. Frederich Wilhelm Bessel, born, in 1784, was a celebrated Prussian who first discovered' the proper motion ■of stars. He . greatly distinguished himself in the field of mathematical astronomy. John Elert Bode was the famous Hamburg astronomer who gave us what is known, as Bode’s Law, which has to do with the distances of planets. His uranographia comprises some 12,000 more stars than any earlier catalogue. i James Bradley (1692-1762) is famous for his discovery of the Aberration of Light and also of Nutation. He was Astronomer Royal at Greenwich, and occupied the Savilian chair of astronomy at Oxford.

Robert Wilhelm Bunsen, of Gottingen (born 1811) shared with Kirchoff the discovery of the secret of the dark absorptive lines of the solar spectrum. He is commonly remembered as the inventor of the burner which bears his name. Professor S. W. Burnham, American astronomer, spent 40 years in the study of double stars, and the science owes a great deal to him." Between 1871 and 1899 he discovered no less than 1290 doubles, to say nothing of his previous findings. The Director of the Lick Observatory, California, Professor W. W. Campbell, should be mentioned for his great achievements with the spectroscope. In 1906 he won the gold medal of the Royal Astronomical Society. Giovanni Cassini, in the 17th century, an Italian by birth, and director of the Paris Observatory, was first to detect the principal division in the rings of Saturn and four of that planet’s satellites. His son Jacques also served with distinction the cause of science. He succeeded his father at Paris, wrote many books on the stars, and suggested the meteoric nature of Saturn’s rings before Clerk Maxwell proved it in 1857. Nicolaus Copernicus (1473-1543), the famous Polish astronomer, taught that the earth and planets revolved .in elliptical orbits around the Sun. It was he, too, who discovered the diurnal rotation of the earth. Upon the foundation, of Copernicus others, like Kepler and Galileo, built. Sir George Darwin, grandson of the esteemed Charles Darwin, originated the theory of tidal evolution, now largely accepted. According to this, about 55,000,000 years ago the earth and the moon were one body rotating rapidly; so rapidly, indeed, that one portion of its mass was thrown off. This part (now the moon) has been receding from the earth ever since. Sir George has made a special study of earth-tides. Much of his best work was done while he was Plumian Professor of Astronomy at Cambridge. Descartes, the great French philosopher, belongs to the 16th century. His discovered the centrifugal forces which balance the action of gravitation. Newton derived much from him. •’

Christian Doppler in 1842 made the almost revolutionary announcement that the speed of light waves determines colour, and that vibrations in the air give a high or low sound according to whether they are fast or slow. Both colour and sound, he stated, depend upon the number of vibrations which enter the eye or the ear in a single second of time. In the case of light or colour the lines in the spectrum are shifted slightly to the blue end when the object is approaching the observer, and towards the red end when receding. The application of this principle—“the Doppler principle”—to a study of the motions of stars has wrought wonders in the realm of astronomical research. Eudoxus of Cnidus (406-350), a Greek astronomer, contemporary with Plato, made many observations of the heavenly bodies from various parts of the world. He was first to systematically describe the constellations. He founded schools at Cyzicus and Athens. Some of Euclid’s propositions are attributed to him. Camille Flammariori, the distinguished French writer, was famous mostly for his astronomical books. These are truly brilliant productions and have been translated into other languages. His fine observatory at Juvisy, near Paris, is well known. He was bom in 1842 at Montigny-le-Roi. John Flamsteed (1646-1719) was the first Astronomer Royal at Greenwich. He compiled a map of the heavens known as the British Catalogue of Stars, the undertaking being carried out with a view to a truer determination of longitude.

(To be continued.) y