Meteors and Meteor Showers

1. Meteors and Meteor Showers www.assignmentpoint.com

2. The Differences… • Meteoroid, Meteorite, Meteor??? • Meteoroid- small, solid body moving within the solar system. • Meteorite- solid remains of a meteor that falls to the Earth. • Meteor- (shooting star)- bright trail of light created by small solid particles entering the Earth’s atmosphere & burning up www.assignmentpoint.com

3. Meteor Facts • Meteors (meteoroids) are the debris associated with comets or asteroids • When a meteoroid enters the Earth’s atmosphere & becomes a meteor, it is traveling at 60-70 km per second! • On a given night (with favorable conditions), you can see 1 meteor every 15 minutes • The typical size of a meteor that produces a visible streak of light ranges from about the size of a grain of sand to the size of a small pebble! (average weight is only around 1 gram!) • Fireballs (large, brilliant meteors) are periodically seen (these may weigh up to several kilograms or more). Bolides are fireballs that explode with a thunderous sound. • See for yourself: • http://www.spaceweather.com/meteors/images/18nov01/varros1_movie.gif (Fireball) • http://www.spaceweather.com/meteors/images/18nov01_page3/Ponder1.MPG (Bolide) www.assignmentpoint.com

4. Why do meteors have a streak of light?? • As they travel through our atmosphere, meteors collide with air molecules that knock away materials and strip electrons from the meteor… • When the stripped atoms recapture electrons, light is emitted… • The color of the light depends on the temperature and the material being “excited.” www.assignmentpoint.com

5. Are all meteors the same color?? • The material or element that makes up a meteor is the main factor that determines the color of its glowing trail… - Sodium = orange-yellow - Iron = yellow - Magnesium = blue-green - Calcium = violet - Silicon = red www.assignmentpoint.com

6. Sporadic Meteors • These are the meteors that can be seen on any given night • They are not associated with any particular meteor shower • They come from random directions in the sky www.assignmentpoint.com

7. Meteor Showers • Heavy displays of meteors that recur from year to year • Caused by small fragments of comet debris entering the earth’s atmosphere at extremely high speeds…when the Earth’s orbit & the comet’s orbit intersect at some point • ‘Shower meteors’ come from the same general point in the sky… • The radiant of a shower is the point in the sky from which the meteors appear to come www.assignmentpoint.com

8. Meteor Showers (cont.) • Meteor showers are usually named for the constellation in which their radiant lies at the peak of the shower… • Ex.: Perseid shower = Perseus • Ex.: Leonid shower = Leo • Ex.: Geminid shower = Gemini www.assignmentpoint.com

9. Specific Meteor Showers • Meteor showers occur on a regular basis throughout the year, but not all are visible in the northern latitudes & some are very weak and easily go unnoticed… • Some of the more impressive showers throughout a given year are: ShowerAvg. Peak - Quadrantids – early January - Lyrids – mid April - Perseids – early/mid August - Orionids – mid/late October - Leonids – mid November - Geminids – mid December ** Historically, the Perseids in August & the Leonids in November have been the most impressive meteor showers - http://www.spaceweather.com/meteors/images/18nov01_page3/cordiale1.mov www.assignmentpoint.com

10. That’s All… www.assignmentpoint.com

11. 3 Questions… 1. True/False: The material or element that makes up a meteor is the main factor that determines the color of the glowing trail left behind True 2. This major meteor shower has a peak time around early/mid August: a. Geminids b. Leonids c. Orionids d. Perseids d. Perseids 3. What is the point in the sky from which all of the meteors seem to come during a shower called? Radiant www.assignmentpoint.com