地球的宇宙环境（The cosmic environment of the earth）.doc

地球的宇宙环境（The cosmic environment of the earth） Third about the earths space environment 1, the (1): the concept of infinite radius sphere for the observer. (2) the location of the observer horizon: tangent on earth. Horizon: the ground plane and the celestial circle. (3) the horizon (circle) position relationship with polaris: The observer at the equator, Polaris is located north of the position. Some observers in the northern hemisphere latitudes, Polaris and horizon (circle) angle The numerical latitude. Observers in the southern hemisphere, the North Star on the horizon (circle), can not see. 2, the universe of celestial bodies. (1) the object type. The natural celestial stars, nebulae, planets, satellites, asteroids, comets and interstellar gas and dust etc.. The most basic is the celestial stars and nebulae. The sun is the nearest star. The star is composed of hot gas, can oneself bulbiform celestial bodies, has great quality. Nebula: cloudy appearance of celestial bodies is composed of gas and dust, the main ingredient is hydrogen. The main component of the volume density of appearance and lighting quality Star ball of gas self luminous small large hydrogen and helium Nebula clouds of gas and dust, no light of its own size smaller hydrogen The planet orbits a star: objects, the solar system has eight planets, Jupiters largest volume, quality. Meteoroid: interplanetary dust particles and solid scrap. Meteoroids entering the earths atmosphere and the formation of air friction phenomena of meteors. Around the large meteoroids the sun along the same track, known as the meteor. Meteor encounter with the earth, people will see a region of a time significantly increased the number of meteors, sometimes even like rain, this phenomenon is called a meteor shower. Most of them are located in or near the constellation radiation star named as leonids. Comet: in a long flat orbit around the sun small objects, a unique cloud like appearance. The famous Halleys comets orbital p