Comets, Asteroids, and Meteors By: Annette Miles What is a comet? A comet is a small body which scientists sometimes call a planetesimal. They are made out of dust, ice rock, gas, and ____. They are kind of like snowball a dirty _________. Comets are made up of different parts. The nucleus The coma The ion tail The dust tail The hydrogen envelope center of a The nucleus is the frozen _______ ice comet’s head. It is composed of ____, gas and dust. The nucleus contains ____, most of the comet’s mass and measure about 10 miles across or less. The nucleus of Halley’s Comet The ______ coma is a spherical blob of gas that surrounds the nucleus of a comet. As the __________ comet gets closer to the sun, the heat vaporizes some of the ice and causes the __________ comet to spew gas and dust particles into space. nucleus The_________and the coma form the _______ head of a comet. ion tail is made of ___________ electrically The _________ charged gas molecules that are being pushed away from the nucleus by the solar wind _____. (The blue tail in the picture.) When a comet is approaching the Sun, the trails the comet: when the comet is ion tail _______ leaving of the Sun, the ion tail leads _____. The tail fades as the comet moves far from the Sun. The ion tail can be well over 100 million km long. The _________ dust tail develops near when the comet is _____ the Sun. This tail is made of small dust particles that have evaporated from the nucleus and are being pushed away from the comet. The tail _______ slightly due to the comet’s motion. The tail can be up to 250 million km long, and is most of what we see. Comets are only visible when they're near the sun in _____ their elliptical orbits. Comet Hale Bopp showing its two tails. Courtesy of NASA http://www.astrographia.com/images/9.jpg Hale-Bopp – The Great Comet of 1997 Surrounding the coma is an invisible layer of hydrogen that has __________ been released. It is the hydrogen envelope . ___________________ This cannot be seen from Earth because its light is absorbed by our atmosphere. It is usually between the ion tail and the dust tail. Can you identify the following parts of a comet? 1. Ion tail 2. 3. Nucleus Coma 4. Hydrogen envelope 5. Dust cloud elliptical Comets orbit the Sun in highly _________ increases greatly when orbits. Their speed _________ slows down at they are near the Sun and ______ the far reaches of the orbit. Since the comet is light only when it is near the Sun, comets are dark throughout most of their orbit. Kuiper Comets originate from either the _______ Belt (beyond the orbit of Neptune) or the _____ Oort Cloud (which surrounds the outer ___________ reaches of the solar system.) Videos on Comets http://videos.howstuffworks.com/hsw/5354-the-small-pieces-comets-video.htm http://www.brainpop.com/science/space/comets/ Animation of a Comet http://www.kidsastronomy.com/comets.htm ASTEROIDS rocky or _________ metallic objects, Asteroids are _______ planetoids or minor planets also know as____________ that revolve around our Sun. Most asteroids orbit the Sun in the asteroid Mars and _________. Jupiter belt located between _______ A few asteroids approach the Sun more closely. The asteroids in the asteroid belt elliptical orbit. have a slightly __________ The time for one revolution around the Sun varies from about 3 to 6 Earth _________ years Asteroids range in size from tiny pebbles to about 578 miles (930 kilometers) in diameter. Sixteen of the 3,000 known asteroids are over 150 miles (240 km) in diameter. • Asteroid Ceres • Diameter of 590miles (950 km) • Largest asteroid and only dwarf planet in the inner Solar System • Asteroid Vesta • Diameter of 326 miles (525 km) • Brightest asteroid visible from the Earth. Some asteroids even have orbiting moons ______. Here is the asteroid “243 Ida” and its tiny asteroid moon, Dactyl. This is the first asteroid ever found with an orbiting moon. Ida's dimensions are about 35 x 15 x 13 miles. Dactyl is only about 1 mile across. METEOROIDS, METEORS, and METEORITES small bodies that travel Meteoroids are ______ through space. Most meteoroids are smaller pebble Meteoroids are than the size of a ________. tiny particles left by an asteroid or a comet. A meteor is a meteoroid that has entered Earth’s atmosphere usually making the _____________________, a fiery trail as it falls. It is sometimes called shooting star or a _______ a _________ falling star. A meteor shower is a phenomenon in which many meteors fall through the atmosphere ______ short time and in in a relatively ______ approximately parallel trajectories. Arizona, November 1966 - The Leonid meteor shower rained 2,300 meteors per minute for 20 minutes. (Photo NASA) Video of meteor Shower http://www.metacafe.com/watch/903546/time_lapse_of_the_perseid_mete or_shower_geminid/ A meteorite is a meteor that has fallen and struck ______ the Earth. These rare objects have survived a fiery fall through the Earth's atmosphere and have lost a lot of mass during that process. Near Winslow, Arizona, you can visit a crater that was made from a meteorite. The crater is nearly one mile across, 2.4 miles in circumference, and more than 500 feet deep. Animation on the formation of this crater. http://www.meteorcrater.com/ RESOURCES http://www.kidsastronomy.com/images/comet2.gif http://www.kidsastronomy.com/comets.htm http://www.nasa.gov/worldbook/comet_worldbook.html http://www.explanet.info/Chapter14.htm http://ed101.bu.edu/StudentDoc/Archives/spring05/aprylh/Lesson1.html http://spaceinimages.esa.int/Images/2002/11/The_nucleus_of_Comet_Halley http://studentastronomyblog1.blogspot.com/2013/02/dirty-snowballs-comets.html http://science.howstuffworks.com/dictionary/astronomy-terms/comet3.htm http://spaceplace.nasa.gov/tails-of-wonder/ http://www.thegalaxyguide.com/galaxy/comets/ http://spaceguard.rm.iasf.cnr.it/NScience/neo/neo-what/com-tail.htm http://www.astropix.com/HTML/SHOWCASE/970401.HTM http://www.solarviews.com/eng/comet.htm http://blogs.saschina.org/julia01pd2014/2010/03/10/lab-answers/ http://www.enchantedlearning.com/subjects/astronomy/activities/label/comet/ http://cse.ssl.berkeley.edu/segwayed/lessons/cometstale/frame_orbits.html http://abyss.uoregon.edu/~js/images/migrate3.gif http://csep10.phys.utk.edu/astr161/lect/asteroids/features.html http://en.wikibooks.org/w/index.php?title=File:Asteroid_belt_between_Mars_%26_Jupiter.PNG&filetimesta mp=20050718221323& http://www.sen.com/feature/space-rocks-comets-asteroids-meteorites-and-more.html http://dustyloft.files.wordpress.com/2008/09/asteroids_comets_sc_0-000-075.png http://en.wikipedia.org/wiki/Ceres_(dwarf_planet) http://en.wikipedia.org/wiki/File:Meteoroid_meteor_meteorite.gif http://rense.com/general42/ukteen.htm http://weblogs.marylandweather.com/2010/01/twilight_meteor_reported_monda.html http://science.howstuffworks.com/dictionary/astronomy-terms/leonid2.htm http://www.meteorcrater.com/