Chapter+12

=The Solar System= http://images.cdn.fotopedia.com/flickr-2818891443-original.jpg =Section 1 Vocabulary( Blue-Definition, Black-Word)= Solar System- a system in space that contains a sun, nine planets, and many other smaller objects.

Early Greeks believed that the Earth was the center of the universe. They also believed that the Sun, moon, and other planets were orbiting the earth in fixed spheres. This is called the Earth-centered model of the the solar system. In 1543 Nicholas Copernicus thought that the Earth wasn't the center of the solar system. He believed that the moon orbited the Earth, but he thought that it was the Sun that was the center of the solar system. Galileo also believed this because he witnessed Venus go through phases like the moon does, so he concluded that this had to be because Venus orbited the Sun. This is called the Sun-centered model of the solar system. Today we know that there are nine planets in our solar system. The Sun takes up 99.86% of he solar system. Because of its immense size, this holds all the planets in its gravitational pull. Scientist believe that the Earth was formed when an nearby star exploded. This created gas and dust to start fragmenting. When these clouds started contracting =Section 2 Vocabulary= Mercury- closest planet to the sun. First American mission to Mercury in 1974-1975(Mariner 10), photographed 45% of Mercury's surface. Surface is similar to the moon, has an iron core, has small atmosphere. Venus- second planet to the sun, similar size and mass to Earth. In 1962 the Mariner 2. Soviets sent first probe to Venus called Venera 7. Mapped and photographed the surface, but stopped working due to Venus' high temperatures and pressure. Earth- Third planet from the Sun, is one Astronomical Unit(AU) from the sun. Unlike other planets, it has an abundance of water and can support life. Earth's atmosphere protects life from the harmful UV rays from the sun. Also the atmosphere causes most meteors to burn up before hitting Earth's atmosphere. Mars- Fourth planet from the sun. Called red planet because of the iron oxide in its soil. Other features include the largest volcano system, Olympus Mons, polar ice caps, and long channels that may have been carved by flowing water. Most of this info. has come from the missions Mariner 9, Viking Probes, Mars Pathfinder, Mars Global, Surveyor, and Mars Odyssey. =Section 3 Vocabulary= Jupiter- Fifth planet from the sun. Largest planet in the solar system. In 1979 Voyager 1 and 2 flew past Jupiter. Galileo and Cassini also flew past Jupiter on their missions. One of its moons has volcanic activity and has a slight dust ring around it. Great Red Spot- Large storm system on Jupiter. Home to strong storm winds and has an ocean of liquid hydrogen and helium. Saturn- Sixth planet from the sun. Second largest planet, but has the lowest density. has a series of large outer rings composed of dust, ice and rock. Uranus- Seventh planet from the sun. Discovered in 1781, has at least 21 moons. Its atmosphere contains hydrogen, helium, and some methane. Scientist think that Uranus has a liquid mantel and a rocky core. Neptune- Eight planet from the sun. Voyager 2 passed Neptune on its mission. Discovered in 1864. Has at least 11 moons, atmosphere similar to Uranus. Pluto- Ninth planet from the sun, smallest in the solar system. Has a 248 year orbit, instead of a gas planet it is a gaseous planet. Has a single moon called Charon and it is half the diameter of Pluto. =Section 4 Vocabulary= Comet- dust and rock particles mixed with frozen water, methane, and ammonia. Meteoroids- pieces of rocks and other substance from the nucleus break off from the comet. Meteor- a meteoroid that burns up in Earth's atmosphere. Meteorite- a meteor that hits the surface of a planet, moon, etc. Asteroid- a piece of rock that is similar to the rock that creates planets. =Quizzes= http://glencoe.mcgraw-hill.com/sites/0078600529/student_view0/unit4/chapter12/section_1_self-check_quiz-eng_.html http://glencoe.mcgraw-hill.com/sites/0078600529/student_view0/unit4/chapter12/section_2_self-check_quiz-eng_.html http://glencoe.mcgraw-hill.com/sites/0078600529/student_view0/unit4/chapter12/section_3_self-check_quiz-eng_.html http://glencoe.mcgraw-hill.com/sites/0078600529/student_view0/unit4/chapter12/section_3_self-check_quiz-eng_.html