The document discusses asteroids, comets, and meteoroids. It explains that asteroids orbit in the asteroid belt between Mars and Jupiter. Comets have icy nuclei and tails made of dust and gas. Meteoroids are smaller than asteroids and become meteors when entering Earth's atmosphere, sometimes surviving as meteorites that hit the ground. Famous comets include Halley's Comet which has a periodic orbit of 76 years.

1. 8 th Grade Chapter 1 Lesson 8 Pgs. 58-63 For Student Use Only

2. Asteroids, Comets, and Meteoroids Asteroids, Comets and Meteoroids all travel through space. Bode’s Law: Mathemtical Formula published in 1772 Bode’s Law: used to find the distance between planets. It found that there should be a planet between Mars and Jupiter On Jan. 1, 1801 an Italian Astronmer discovered the asteroid belt between Mars and Jupiter

3. Asteroids, Comets, and Meteoroids Asteroid Belt: Located between Mars and Jupiter The Italian Astronomer that discovered the asteroid belt, named it Ceres. (He thought it was a small planet.) It was soon found that Ceres was too small to be a planet and there were many other smaller objects around Ceres. Asteroids are tiny “planets” or tiny chunks of rock

4. Asteroids, Comets, and Meteoroids Asteroids: Most asteroids traveling through the asteroid belt are grouped in clusters and have their own orbits. They can sometimes crash into each other when their orbits are changed by gravitational pulls from other planets or asteroids. They can come free of the asteroid belt when the gravitational pull of a planet pulls them out of orbit.

5. Asteroids, Comets, and Meteoroids Asteroids Most asteroids are not round like planets. They are oblong. Some asteroids are not in the asteroid belt. Jupiter’s Ateroids- Trojan asteroids Apollo Asteroids- Follow individual paths and come close to Earth

6. Asteroids, Comets, and Meteoroids Comets: Tycho Brahe: discovered asteroids were not “invading” the Earth’s atmosphere, but were a natural part of the Solar System Newton said comets follow the same rules of motion as the planets. Edmund Halley proved Newton was correct by calculating the orbit of a comet and predicting when it would be visible again to Earth This comet is called Halley’s Comet

7. Asteroids, Comets, and Meteoroids Comet: Comets have different parts. Nucleus: The frozen chunk of ice at the head of the comet. (It is a dirty snowball.) Coma: The gas and dust cloud created from the melting nucleus as it gets closer to the sun Tail: The dust and gas particles that are wafted away from the coma in a blazing stream Solar Wind- (the stream of charged particles from the sun) help create the comets tail

8. Asteroids, Comets, and Meteoroids Comet Comet means “long-haired star” Called “comet” because of the tail The tail usually has different colors Dust- glows a yellow color (reflects sunlight) Gas- glows a bluish tint (reacts with the solar winds)

9. Asteroids, Comets, and Meteoroids Comet Comets orbits are VERY ellipitical The amount of time it takes for a comet to complete an orbit is called a period . Enck’s Comet- has a period of 3 years and 4 monthes (shortest) Halley’s Comet- has a period of 76 years. Last appeared in 1986

10. Asteroids, Comets, and Meteoroids Meteoroid Meteoroid- a smaller chunk of rock (or other space debris) than an asteroid Meteors- Meteoroids that enter Earth’s atmosphere (AKA. Shooting stars)- they usually burn up in the Earth’s atmosphere Meteor Shower- when Earth passes through a cluster of meteoroids- Named for the constellations they appear to radiate from

11. Asteroids, Comets, and Meteoroids Meteoroids Some meteors hit the earth These meteors are too large to completely burn up in our atmosphere and will hit the Earth’s surface and become part of the soil. These meteors that hit the earth’s surface are called Meteorites ! Meteorites are usually very small.

12. Asteroids, Comets, and Meteoroids Meteoroid Facts Largest intact meteorite was found in Africa and weighed 66 tons. Largest meteorite hit near Flagstaff, Arizona (thousands of years ago) and was probably 650 ft. in diameter and created a crater 4000 ft. deep.