Even an opera-glass will give a view of Jupiter as a minute disk with two bands across its center and four luminous points on either side. These luminous points are satellites, three of which are larger than our moon and one almost as large. Jupiter has nine satellites in all but only four are visible in any but the most powerful telescope and three cannot be seen except in photographs. The four large satellites may be seen to change their positions from hour to hour, occasionally disappearing in the shadow behind Jupiter, and then reappearing with startling abruptness on the other side. [Figure 149: THE PLANET JUPITER. Photographed by Yerkes Observatory through the 40-inch refractor.] With a stronger glass they may be seen moving as bright spots across the face of the planet, followed or preceded by the dark disks of their shadows. With a large telescope, various colored belts are seen to streak this globe like dark stripes from east to west, the most prominent ones being the two deep red bands some 7000 miles broad which lie on either side of a faint golden equatorial belt, some 6000 miles across. Besides these, there are lesser belts to the north and south which are red, green, brown, black and brilliant white. The spots on the equatorial belt move rapidly toward the west with a speed of over 270 miles an hour, with respect to the other markings on the planet. By watching these impressive colorings and markings the gigantic globe may actually be seen to turn around on its axis! It does this in only 9 hours and 50 minutes--less than half the time that it takes the earth to rotate. With a still larger telescope, however, it was discovered that 9 hours and 50 minutes was only the average time that it takes Jupiter to rotate and that the day varies according to the location on the planet. Thus, like the sun, its surface is not a fixed one, for at the equator the rate of rotation is 9 hours and 47 minutes, a little distance at either side 9 hours and 56 minutes, and in higher latitudes over 10 hours. But Jupiter is not as hot a globe as the sun, which has been described as somewhat resembling "thick molasses," for if it shone by its own light it would not cast a shadow, nor would the shadows of its satellites be dark spots upon its surface. Such facts have led to the general belief that Jupiter is still in an early stage of development with its globe probably in a semi-fluid condition so hot that the gases which will some day form its waters and be cradled in the hollows of its crust, now rise as hot vapor into its thick, warm atmosphere and fall as incessant rains. The surface visible to us on earth must therefore be in the nature of dense clouds and vapors while its real surface is probably in a "hot, muddy thickish liquid" condition, quite unattractive to think about.