Asteroids, meteors, meteorites

1. Asteroids, meteors, meteorites Heather, Tirzah, Trinity

2. Number of moons ● asteroids, meteors, and meteorites have around 1 moon in all.

3. Periods of rotation and revolution • The periods and revolution of our topic is around 1.88 and 11.86 earth years.

4. Location and reference to the Sun

5. Physical properties • Meteors have a variety of physical properties. Some are icy, others dusty clumps and still others are dense and crystalline. The ones that survive the plunge to Earth are meteorites and are typically dense and can be rock, metal or crystalline in structure. • Asteroids are commonly classified into types according to their spectra. Among these types are type C, type S, and type M. Type C asteroids are extremely dark and comprise more than 75% of all asteroids. Type S asteroids are relatively light asteroids composed of metallic nickel-iron and make up 17% of all asteroids. Most of the other asteroids are type M, which are bright asteroids composed of pure nickel-iron. There are a few other rare types of asteroids. • Meteorites are basically the same thing as meteors.

6. Extra info • Meteorites vary in size and, fortunately, most of them are small. • meteors are usually larger than those left behind by comets and are more likely to become meteorites by striking the Earth. • Asteroids, which are sometimes referred to as minor planets, are rocky, metallic bodies that revolve around the Sun, usually in a region known as the Asteroid Belt.

7. History of asteroids • 1950 -- Immanuel Velikovsky publishes "Worlds in Collision" (see bibliography), a pseudoscientific warning about impact hazards. In equal parts bogus and frightening, Velikovsky casts the entire field of impact studies into disrepute. • 1980 -- Spacewatch program starts at the University of Arizona, intent on cataloging asteroids. The goal is to get a statistical picture of orbiting rocks anywhere in the solar system. • 1980 -- Physicist Luis Alvarez and his team blames the dinosaur extinction on the environmental havoc of a collision. The resulting firestorm and a global soot and dust cloud, they argue, cooled the planet enough to make the dinos long for a package vacation in Cancun. Many scientists, including renowned comet hunters, smirk in their beer about this ridiculous notion, which only gains acceptance after a 180-kilometer wide crater is discovered north of the Yucatan. • 1994 -- Comet Shoemaker-Levy 9 breaks apart, then smashes into Jupiter under the watchful eye of dozens of telescopes. The resulting zone of chaos is estimated to be as large as the Earth and lends urgency to the search for asteroids and comets. "Shoemaker-Levy was a turning point," says Benny Peiser, an anthropologist at Liverpool John Moore's University at the 2000 meeting of the American Association for the Advancement of Science in Washington, D.C. In the course of presenting results of the computer simulation on asteroid impacts, Peiser adds, "If it can happen in front of your nose -- practically in your backyard -- it can also happen on Earth." • 1998 -- Astronomers announce that an asteroid may be on a collision course for Earth. The warning is quickly withdrawn after further observations.

8. History of meteors • Throughout history, meteors and meteorites have had an enormous impact on people on Earth, on events on Earth, and even the Earth itself. First, before this historical account begins, we need to have Meteors 101, how to tell the difference between meteors in all their forms. A meteoroid is a rock in space. They can be anywhere from the size of a grain of sand to the size of a house and much larger. A meteor is a meteoroid that has begun burning up in the atmosphere (also known as a shooting star). A meteorite is a meteor that did not burn completely in the atmosphere and has landed on Earth. A very large meteoroid is also known as an asteroid.

9. History of meteorites • Throughout the ages, meteorites were venerated as sacred objects by different cultures and ancient civilizations. The spectacular fall of a meteorite, accompanied by light and sound phenomena, such as falling stars, smoke, thunder, and sonic booms, has always kindled the human imagination, evoking fear and awe in everyone who witnesses such an event. For obvious reasons, the remnants of these incidents, the actual meteorites, were often kept as sacred stones or objects of power. They were worshiped, and used in their respective religious ceremonies.

10. Has someone or something ever been to your topic? • 11 comets and asteroids have been explored by spacecraft so far, as follows: ICE flyby of Comet Giacobini-Zinner. Multiple flyby missions to Comet Halley. Giotto (retarget) to Comet Grigg-Skellerup. Galileo flybys of asteroids Gaspra and Ida (and Ida satellite Dactyl). NEAR-Shoemaker flyby of asteroid Mathilde on the way to orbit and land on Eros. DS-1 flybys of asteroid Braille and Comet Borrelly. Stardust flyby of asteroid Annefrank and recent sample collection from Comet Wild 2. For future we can expect: Hayabusa (MUSES-C) to asteroid Itokawa, Rosetta to Comet Churyumov-Gerasmenko, Deep Impact to Comet Tempel 1, and Dawn to orbit asteroids Vesta and Ceres. • Read more about Asteroids  l  Asteroid facts, pictures and information by nineplanets.org