- The Egyptians cultivated astronomy from a remote antiquity—11,000 years ago, according to Herodotus. Diodorus states that they were able to calculate eclipses. Their year, consisted of 365 days.
The Chaldeans are said to have made observations reaching back to 2200 B.C. They learned to predict eclipses by means of their discovery of the eighteen year cycle, called the Saros: similar series of eclipses recur in successive cycles.
The Hindoos seem to have possessed an extensive knowledge of astronomy in olden times, but the dates of their writings are very uncertain.
The Chinese refer the beginning of their astronomical observations to a date about 3000 B.C. About 2600 B.C, the emperor Hoang Ti established a mathematical tribunal for the purpose of correcting the calendar and predicting eclipses. Their records after 720 B.C. seem to be authentic. They contain accounts of eclipses and of remarkable comets.
B.C. 640-548 Thales, the chief of the Seven Sages, flourished. He was the founder of the Greek school of Astronomy; he taught that the moon receives its light from the sun, while the stars are self-luminous; he believed that the earth was a sphere.
*Taken largely from Howe's "Elements of Descriptive Astronomy."
B.C. 569-470. Pythagoras, of Samos, is reputed to have taught his disciples that the earth was not the center of the universe, but that there was a central fire about which the sun, moon, earth, planets, and stars revolved.
B.C. 433. Meton, an Athenian, discovered the "Metonic Cycle," which is still used in finding the time of Easter. The cycle embraces 235 synodic months, which are almost exactly equal to 19 years of 365 1/4 days each. This cycle is also of use in predicting eclipses.
B.C. 190-120. Hipparchus, of Nicea in Bithynia, did the memorable work which has given him the appellation of the Father of Astronomy. He was the first to use right ascensions and declinations, and made the earliest catalogue of stars. He devised the method of locating places on the earth by latitude and longitude, discovered the precession of the equinoxes, calculated eclipses, divided the day into periods of twelve hours each, and determined the periods of the planets.
A.D. 100-170. Ptolemy, the Alexandrian astronomer, produced a number of astronomical and geographical works, the most celebrated of which is now known as the Almagest, a name given by the Arabians. The theory of the celestial motions which he advocated is known as the Ptolemaic theory, and enthralled astronomers for 1,400 years. It placed the earth, a motionless sphere, in the center of the universe, which revolved about it.
A.D. 1214-1294. Roger Bacon laid the foundations of the modern experimental method in science, afterwards elaborated by Francis Bacon: he was a conspicuous champion of intellectual liberty.
A.D. 1543. The great work of Copernicus, entitled De Revolutionibus Orbium Celestium, was published. This work set forth the theory that the sun is the center of the solar system. The theory gained acceptance only after a sturdy battle with the adherents of the Ptolemaic system, which had been generally believed for fourteen centuries.
A.D. 1576. Tycho Brahe, a Dane, rejected the Copernican theory, retained the earth as the center of the universe, made the sun revolve about the earth, and the planets about the sun. The instruments which he employed in his observations were much more accurate than any others that had ever been constructed.
A.D. 1610. Galileo, of Pisa, invented the telescope, which revealed the moons of Jupiter, mountains on the moon, the phases of Venus, etc.
A.D. 1609. Kepler published his laws of planetary motions.
A.D. 1687. Newton published the Principia, universally conceded to be the masterpiece of the world's scientific thought.
A.D. 1705. Halley predicted that the Great Comet of 1682 would return in 1759.
A.D. 1727. Bradley, an English astronomer, discovered the aberration of light. A.D. 1781. Hadley invented the sextant, which has proved invaluable to mariners.
A.D. 1781. Sir William Herschel discovered the planet Uranus.
A.D. 1801. Piazzi, of Palermo, discovered Ceres, the first minor planet.
A.D. 1840. The moon was first photographed by Dr. J. W. Draper, of New York.
A.D. 1846. The planet Neptune was discovered: this is esteemed the greatest triumph of mathematical analysis.
A.D. 1859. Spectrum analysis, which has lately yielded marvellous results, entered the service of astronomy.
A.D. 1868. The sun's prominences were observed by Jansen and Lockyer by means of the spectroscope, in full sunshine: they had hitherto been seen only during total solar eclipses.
A.D. 1877. The satellites of Mars were discovered by Professor Asaph Hall, with the twenty-six inch telescope of the United States Naval Observatory, at Washington.
A.D. 1892. The fifth satellite of Jupiter was discovered by Barnard.
A.D. 1895. Saturn's rings were spectroscopically proved by Keeler to be composed of small bodies. Helium was found to be widely disseminated throughout the universe.
A.D. 1898. The notable asteroid Eros was discovered by Witt, at Berlin.
A.D. 1899. W. H. Pickering announced the discovery of Phoebe, the ninth satellite of Saturn.
A.D. 1900-1. The pressure exerted by solar radiation was measured.
A.D. 1905. The discoveries of the sixth and seventh satellites of Jupiter were announced by Perrine. W. H. Pickering discovered Themis, the tenth satellite of Saturn.
A.D. 1908. Melotte discovered the eighth satellite of Jupiter.
A.D. 1917. A series of observations of phenomena at the earth's surface resulted in the revolutionary discovery that the earth's surface is concave, instead of convex. A new era of science inaugurated. KELLY AND WALSH, LTD., PRINTERS. ---
← Appendix C — 75 Vital Questions
- -- Source: O. F. Barcus, A New World Discovered (1917).