... On the equator (point C) the sun would always rise until it was overhead, while at the poles (A and B) it would always be on the horizon, going around the horizon once a day. ... Because everything is symmetric with respect to the line AB, the dark and light portions are always equal, and so are day and night, anywhere on Earth. ... Twice a year, the angle is as big as it can get, at the summer and winter solstices , when it reaches 23.5 degrees. ... That part of Earth enjoys summer . ...

... Sphere . 1b. Pole Star . ... The Sun rules by daytime sky, but at night, especially if the Moon does not shine, the show belongs to the stars. ... To ancient observers it seemed as if Earth was at the center of a giant star-studded " celestial sphere ," which reinforced the belief, held for thousands of years, that we are at the center of the universe. ... Like the globe in the drawing, the sphere of the sky has two points around which it turns, points that mark its axis --the celestial poles . ...

The Discovery of the Galilean Satellites . ... Probably the most significent contribution that Galileo Galilei made to science was the discovery of the four satellites around Jupiter that are now named in his honor. Galileo first observed the moons of Jupiter on January 7, 1610 through a homemade telescope. He originally thought he saw three stars near Jupiter, strung out in a line through the planet. ... Galileo's Observations of Jupiter's Moons . ... Jupiter . ...

Cosmic Research, Vol. 42, No. 5, 2004, pp. 435­488. Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 5, 2004, pp. 453­508. Original Russian Text Copyright © 2004 by Veselovsky, Panasyuk, Avdyushin, Bazilevskaya, Belov, Bogachev, Bogod, Bogomolov, Bothmer, Boyarchuk, Vashenyuk, Vlasov, Gnezdilov, Gorgutsa, Grechnev, Denisov, Dmitriev, Dryer, Yermolaev, Eroshenko, Zherebtsov, Zhitnik, Zhukov, Zastenker, Zelenyi, Zeldovich, Ivanov-Kholodnyi, Ignat'ev, Ishkov, Kolomiytsev, Krasheninnikov, Kudela,