Asteroids, Meteroids, and Comets…Oh my! Asteroids Asteroids – A rocky lump of frozen gas that can range in size from a few hundred feet.
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Asteroids, Meteroids, and Comets…Oh my! Asteroids Asteroids – A rocky lump of frozen gas that can range in size from a few hundred feet to several hundred miles wide. Matter that is similar in composition to the planets. Sometimes, it’s called a Planetoid. Orbit in a belt between Mars and Jupiter. Largest asteroid known: Ceres (1801) Asteroid Gaspra – photographed by the Galileo spacecraft in 1991. What prevents the Asteroids in the belt from plunging into the sun and hitting the inner planets in the process? The Sun’s gravity and Jupiter’s gravity! Meteoroids Meteoroids – Small fragments of matter, like rock, stone, and metals (smaller than asteroids) that orbit the sun at a variety of speeds; pieces of planets, moon, or asteroids Meteor - “shooting star” • This happens when a meteoroid enters Earth’s atmosphere and begins to burn. • Briefly visible • Fireball – Long streaks of bright light created by these racing meteors Fireball from a meteor in the night sky. Pennsylvania 1992 Sometimes meteors strike Earth! Meteorite – a meteor that impacts the ground. • Most meteorites fall into the oceans. • Most meteorites fall to earth as dust, because they burn up in the atmosphere. • “Micrometeorites” strike Earth daily. These can be as small as pebbles. • Size of a mountain every 10,000 years. • Craters are created when large meteorites strike a moon or planet. 3 km wide in Quebec, Canada Largest Meteorite to strike US – Oregon 1902 1954 – crashed through the living room and injured a woman. What’s the difference between a meteoroid, meteor, and meteorite? Meteoroid – still in space Meteor – enters earth’s atmosphere Meteorite – meteor that strikes earth because it’s so big it doesn’t burn up. Seen during a football game. Pieces of it crashed into the trunk of a parked car. Meteor Shower The 1966 Leonids Meteor Shower Arizona; 2300/minute for 20 minutes Comets Comets – lumps of frozen gas and rock that orbit the sun in a highly eccentric way. A heavenly body that is usually named after its discoverer. Believed to originate in an Oort cloud. (Huge cloud that is thought to surround our solar system). Nucleus – the center of a comet. Coma – large halo of gas and dust that forms around the nucleus of a comet when it gets close to the sun. It actually loses mass as it gets close to the sun. More about a comet Comets orbit the sun in an elliptical pattern. Comets have tails. Their tails are made of frozen gases, cosmic dust, and rocky particles. As a comet travels toward the sun, its head leads the way. But as it travels away, its tail leads the way. This is due to Solar winds. Haley’s comet – a space curiosity that returns to Earth’s view every 76 years. Haley’s Comet It has been spotted for thousands of years. Sir Edmond Halley – English astronomer (1656-1742) Can you find Haley’s Comet in the tapestry below dated from 1066 A.D.?