Downloaded 37 times
More Related Content
Meteor Showers
- 1.
- 2. Meteor Science isa new Science • Earliest reference by Chinese astronomers in 1809 BC • Not scientifically believed to exist until the great Leonid meteor shower of November 1833 • Many Americans observed 1,000 meteors per hour during the Leonids “I would more easily believe that (a) Yankee professor would lie than that stones would fall from the heavens” - Thomas Jefferson
- 3. What is aMeteor • Rocky material in space is called a meteoroid • Rocky material entering the atmosphere is called a meteor • Rocky material surviving long enough to land on the ground is called a meteorite
- 4. What is aMeteor • Meteors become visible 50 to 60 miles above the ground • Most meteors are only the size of a grain of sand or a pebble • Meteors are fast, between 11 and 70 miles per second • Meteors glow brightly as they streak across the sky (lasting for only a few seconds) • Most cease to exist tens of miles above the ground • Average of seven meteors per hour (sporadics)
- 5. Big Surprise • Ameteor’s emission of light is not due to friction
- 6. Hypersonic Reentry • Hypersonicreentry creates shockwaves in the rarified upper atmosphere • Shockwaves occur when a meteoroid slams into air molecules faster than they can move out of its way (which is the definition of the speed of sound)
- 7. Hypersonic Reentry • Shockwavesheat the atmosphere to 3,000O F • Air this hot glows • The hot shockwave ahead of the meteoroid roasts the meteoroid • A melting/vaporizing meteor also glows, but represent only 5% of the meteor’s light
- 9. Extreme Meteors • Verybright meteors (brighter than Venus) are called Fireballs • Exploding meteors are called Bolides • Fireballs and Bolides imply very large meteoroid bodies
- 10. Sources of Meteors •Comet dust is the source for most annual showers • Asteroids are the best source for meteorites found on the ground
- 12. What is aMeteor Shower • Trails of billions of tiny meteoroids orbit the sun • Each trail is like a closed ring circling the sun • These rings are called meteor streams • There are more than 80 different meteor streams orbiting the sun • Each stream has a different size, shape, and tilt
- 13. When do MeteorShowers Occur • Meteor showers occur where meteor streams and Earth intersect • This usually occurs once per year for each stream • Each shower can last for days
- 14. Observing Meteor Showers •Dress warmly (even in summer) • Observe at a dark location away from lights • Observe when the moon is below the horizon • Usually best observed after midnight (when we face into Earth’s direction of travel around the sun) • Look away from the radiant
- 15. Radiant • The pointin the sky where meteors in a single shower appear to originate • Controlled by orientation of the meteor stream relative to Earth
- 16. Popular Meteor Showers • • • • • • Quadrantids:2-3 January Lyrids: 20-21 April Perseids: 12-13 August Orionids: 20-21 October Leonids: 17-18 November Geminids: 13-14 December
- 17. Four Notable Meteors •KT Event (Cretaceous-Paleogene extinction event) • Tunguska • Chelyabinsk Meteor • First extraterrestrial meteor shower
- 18. The K-T Event •66 MYA • 75% of all species went extinct • We are here today because dinosaurs did not have a space program
- 19. Tunguska Event (1908) •June 30, 1908 • Sparsely occupied part of Siberia • Meteor exploded with the force of 12 MT (hydrogen bomb power)
- 20. Chelyabinsk Meteor • February2013 • Widely recorded on dash cams • The sonic boom broke windows and collapsed a building roof • About 50 people hospitalized for cuts
- 21. First Extraterrestrial meteorShower • March 7, 2004 • Spirit Mars Rover
- 22.