THE GIANT OF THE PLANETS
THE LATEST ASTRONOMICAL DISCOVERIES and opinions regarding the great planet Jupiter are briefly gathered in a leaflet issued by the Astronomical Society of the Pacific (San Francisco). In it, E. C. Slipher, of the Lowell Observatory, Flagstaff, Arizona, tells us that Jupiter’s claim on our interest is not so much because of his bodily form or great size, or because he forms the chief ornament of our night sky, but rather by reason of the conspicuous part he has played in the historical development of astronomy and the interesting example he presents in planetary evolution—a chaotic something between sun and world. Mr. Slipher writes:
“Long ago it was learned that he was the giant of the planets, standing fifth in order of distance from the sun; that his size is greater than that of all the other planets combined; that his diameter is so great that even at his tremendous distance he shows the largest disk of any of the planets, and shines with a brilliancy equaling that of any of the other planets except Venus; that his great circumference of 271,750 miles combined with his rapid rotation once every 9 hours and 50 minutes, causes particles on his equator to travel at the speed of 26,000 miles per hour, almost equaling his orbital speed of 28,800 miles per hour; that his density is only one-quarter that of the earth, but that his mass is such that objects on his surface weigh two and five-eighths times as much as they would on the earth.
“His satellite system of nine members has played a unique part in astronomical discovery. First, because the four largest ones were the first objects revealed by Galileo’s crude telescope in 1610; second, because it was from the variability in the time of occurrence of their eclipses that Roemer discovered, in 1675, the finite velocity of light; third, because it was from a study of their motions that an early determination of the mass of Jupiter was deduced.
“It was not until 1892 that his tiny fifth satellite was discovered by Barnard at the Lick Observatory, while the still fainter sixth, seventh, eighth and ninth satellites were more recently detected only by the means of photography, three at the Lick Observatory, one at Greenwich.
Planet Jupiter knowledge continued here…
Source: The Literary Digest for November 5, 1927