Meteors & Meteor Showers

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

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)

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.”

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

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

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

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

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: Shower Avg. 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

That’s All…

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

References… http://csep10.phys.utk.edu/astr161/lect/meteors/showers.html http://www.sky-watch.com/meteor.html http://hometown.aol.com/theleonids/ http://www.geocities.com/~starwanderer/meteor.htm http://www.meteorobs.org/showers.html http://www.amsmeteors.org/showers.html