1. Tuesday, January 17, 2012  Comets are known as what?  The comet’s ion tail always extends where?  Most asteroids can be found in the ______ __________?

2. TCAP Thursday!! 1/12/12

3. In your Table of Contents…  Did you add “Sun Notes” yesterday? If not, please add that.  For today, add “Comets, Meteors, and Asteroids Notes”

4. Comets, Asteroids, & Meteors In addition to planets and moons, the solar system contains many other types of objects, including comets, asteroids, and meteoroids.

5. Comets  A comet is a small body of ice, rock, and cosmic dust loosely packed together.  Known as “dirty snowballs.”  When a comet passes close enough to the sun, solar radiation heats the water ice so that the comet gives off gas and dust in the form of a long tail.  The ion tail consists of electrically charged particles of gas.

6. Comet Orbits  The difference between the orbit of a planet and the orbit of a comet is that a comet's orbit is highly elliptical and a planet's orbit is only slightly elliptical, but more circular.  The comet’s ion tail always extends away from the sun.  This is because the ion tail is blown away from the sun by the solar wind.

7.  When the comet Shoemaker-Levy 9 broke apart and fell into Jupiter, some of the fragments generated explosions that produced fireballs larger than Earth.

8. Asteroids  Asteroids are small, rocky bodies in orbit around the sun.  Have irregular shapes  Most asteroids orbit the sun in a wide region between the orbits of Mars and Jupiter, called the asteroid belt.

9. Types of Asteroids  Outer region of the asteroid belt = dark reddish brown to black surfaces  A little closer to the sun = dark gray surfaces  Innermost part of the belt = light gray asteroids  Examples: Hektor, Vesta, and Ceres

10. Meteoroids  A meteoroid is a small, rocky body orbiting the sun.  Meteoroids are similar to asteroids, but they are much smaller.  In fact, meteoroids probably come from asteroids.

11. Meteoroids  If a meteoroid enters Earth’s atmosphere and strikes the ground, it is then called a meteorite.  Stony, metallic, and stony-iron are the three major types of meteorites.  It travels at such high speeds that it heats up and melts.  As it burns up, the meteoroid glows red hot and gives off an enormous amount of light.  From the ground we see a streak of light or shooting star.  The bright streak of light caused by a meteoroid or comet dust burning up in the atmosphere is called a meteor.  Some meteors that hit the ground can cause craters.

12. Meteor Crater  Planets and moons that have no atmosphere have many more impact craters than those that do have atmospheres.  Earth’s atmosphere acts like a shield.

13.  In 1954, Mrs. E. Hulitt Hodge, of Alabama, was struck by a meteorite as she was taking her afternoon nap. Bruised, but not badly injured, she is one of only two people known to have been struck by a meteorite.