Is Jupiter Launching a Moon? 



The mysterious Great Red Spot on the biggest 

 of planets and what it means to astronomers 



IF JUPITER were cut up into one 

 thousand three hundred pieces, each 

 would be larger than the Earth. All 

 the planets together do not weigh half 

 as much as Jupiter. Only the Sun 

 surpasses Jupiter in size. 



A year on the planet Jupiter is equal 

 to twelve of our years. Jupiter rotates on 

 his axis in less than half the time of the 

 Earth. But because of the planet's 

 enormous size, the rotation speed is 

 much higher. While the Earth travels 

 17 miles a minute, Jupiter travels 

 466 miles a minute. If Jupiter turned 

 on its axis a little faster, it would burst 

 as some flywheels do, when they exceed 

 a safe speed. 



Jupiter may be regarded either as a 

 decaying sun or a developing earth. He 

 has not yet had time to cool. He is a 

 great globe of gaseous and molten • 

 matter — the most extraordinary planet 

 in the entire solar system. 



Because Jupiter is a semi-sun, there is 

 some reason to believe that he possesses 

 inherent light of his own. But astrono- 

 mers are by no means in accord on this 

 point. Perhaps the clouds, that certainly 

 exist on Jupiter, owe their origin to some 

 other heat than that of the Sun. In 

 other words, Jupiter possesses stores of 

 heat within liimselt. 



Look at Jupiter through a fairK' pow- 

 erful telescope and you will see two 

 broad belts with two or three narrower 

 ones on either side. They lie practically 

 jiarallel to the planet's equator. Some- 

 times they are narrow, and when they 

 are very narrow, there is an increase in 

 their number. 



Since Jui)iter is in a more or less 

 fluid condition, he is surrounded by a 

 dense, cloudy envelojie. In all likelihood, 

 the belts are simply rifts in this envelope, 

 exposing the more solid portion of the 

 planet beneath. Not mtich is known 

 about the bi-lts. While they remain 

 unchanged for months, the fact that they 

 do alter their ai)i)earance has led to the 

 assumiitinn liiat gri'at atmosi)heric 



storms take place on Jiqiiter. 



Occasionally Jupiter's belts appear 

 spotted. Just what these spots are, no 

 one knows definitely. 



It was in 1878 that the great, mysteri- 

 ous Red Spot of Jupiter, which has 

 puzzled astronomers for many years, 

 was first observed at Brussels by 'SI. 

 Niesten. It was 30,000 miles long one 

 way and over 8,000 miles another. 

 The Earth might figuratively have been 

 dropped' into the Red Spot without 

 touching the sides. 



For three years, the Great Red Spot was 

 a constant object of study. It completed 

 its circuit about Jupiter in nine hours, 

 fifty-five minutes and thirty-six seconds. 



What is the Great Red Spot? A 

 volcano, said some. That is impossible, 

 because it floats freely. It has a strange 

 effect on its surroundings; it has the 

 property of excavating them, as it were. 

 There is a deep bay in which the spot, 

 rather dim now, is located. 



In describing the drawing appearing 

 on the opposite page, Mr. Scriven 

 Bolton, the English astronomer who 

 made it says: 



"It is propounded th.it our earth, when 

 once in a plastic condition, rotated on its 

 axis so swiftly that the matter at the 

 equator could not adhere together, and a 

 • breach caused a portion to be fractured, 

 wliich portion gradually separated from the 

 parent planet. So, apparently, in the case 

 of our cousin-planet Jupiter, whose rota- 

 tional velocity at its surface is as great as 

 ours used to be, there is at present a phe- 

 nomenon which suggests an epoch in the 

 evolution of moon-making. That puzzling 

 object on the surface, known as the t'.reat 

 Red Spot, is not a fixture of the Surface, or 

 we miglu regard it |)urcly as a volcanic vent 

 emitting hot vapors. Its constituent proper- 

 ties have never been ascertained. ... It 

 moves round with the planet's axial rotation. 

 This is especially notewortliy from the 

 fact that theory tells us thai our moon, in 

 its early stages of evolution, was carried 

 round with the earth's axial motion, all 

 the while just grazing the surface, and that 

 its distance therefrom increased through 

 countless ages, and is increasing. The in- 

 ference denotes a Jovian moon in embryo." 



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