Comets, Asteroids & Meteorites

Comets - Comets are cosmic snowballs of frozen gases, rock and dust roughly the size of a small town - Each comet has a tiny frozen part, called a nucleus, often no bigger than a few kilometers across. The nucleus contains icy chunks and frozen gases with bits of embedded rock and dust. - A comet warms up as it nears the sun and develops an atmosphere, or coma. The sun's heat causes ices on the nucleus surface to change to gases so that the coma gets larger. The coma may be hundreds of thousands of kilometers in diameter. -The pressure of sunlight and high-speed solar particles (solar wind) blows the coma materials away from the sun, forming a long, and sometimes bright, tail..

Where are They? -Long-period comets (those which take more than 200 years to complete an orbit around the Sun) originate from the Oort Cloud -Short-period comets (those which take less than 200 years to complete an orbit around the Sun) originate from the Kuiper Belt.

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● Asteroids ● An asteroid is a rocky object in space that's smaller than a planet — they're sometimes called minor planets or planetoids ● Asteroids have no atmosphere, but many are large enough to exert a gravitational pull — some, have one or two companion moons, or they form binary systems, where two similarly sized asteroids orbit each other.

Types of Asteroids ● The asteroids that are nearest the Sun are mostly made of carbon while the ones further away are made up of silicate rock ● C type are found in the outer areas of the main belt and are darker and more carbonaceous then the S type. ● S type are found in the inner area of the main belt, closer to Mars, and are composed of mostly stone and iron.

● Types of Asteroids ● D type are also known as the Trojan asteroids of Jupiter and are dark and carbonaceous in nature. ● V type are a far out group. They hang out between the orbits of Jupiter and Uranus and are made of igneous, eruptive materials.

● Asteroids are in the Asteroid belt inside the orbit of Mars ● The dangers of asteroids and comets – YouTube The dangers of asteroids and comets – YouTube

● Meteors ● A meteor is an asteroid or other object that burns and vaporizes upon entry into the Earth's atmosphere ● Commonly known as "shooting stars"

● Meteorites ● If a meteor survives the plunge through the atmosphere and lands on the surface, it's known as a meteorite ● Meteorites are categorized as iron or stony. Iron meteorites are composed of about 90 percent iron; stony meteorites are made up of oxygen, iron, silicon, magnesium and other elements

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● Bibliography ● "Solar System Exploration: Planets: Asteroids: Overview." Solar System Exploration: Planets: Asteroids: Overview. N.p., n.d. Web. 07 May ● "What Are Asteroids Made Of?" Universe Today RSS. N.p., n.d. Web. 07 May ● "What Are an Asteroid, a Meteor and a Meteorite?" LiveScience.com. N.p., n.d. Web. 07 May 2013.