Comets, Meteors, and Asteroids
Structure of a Comet Ion Tail Dust Tail Coma To Sun
Comet Structure Nucleus Coma Tail 10 km “Dirty Snowball” Cloud of evaporated ices and ions may be 100,000 km in diameter Tail Always points away from Sun Due to Solar Wind & Radiation Pressure
The Oort Cloud In 1950 Jan Oort noticed that no comet has been observed with an orbit that indicates that it came from interstellar space, there is a strong tendency for aphelia of long period comet orbits to lie at a distance of about 50,000 AU, and there is no preferential direction from which comets come.
The Oort Cloud
Comet Halley
Bayeaux Tapestry Norman Invasion of 1066
Comet Halley 1910 Pope Callixtus III excommunicated Halley's Comet in 1456 In 1910, charlatans sold "comet pills" Orbit
Comet Nucleus
Comet of 1577
Comet Pons-Encke, 1804
Hyakutake
Hale-Bopp
Comet West
The Cause of Meteor Showers P55/Tempel-Tuttle
Why After Midnight is Best Orbital Velocity Rotational Velocity
Shower Radiant The ‘leftovers’ of a comet. Apparent point of origin of a meteor shower.
Shower Radiant
The 1833 storm
The 1966 storm
1997 Leonids from Orbit
Two Showers for Halley
Carbonaceous Chondrite Sporadic Meteors Irons Stony-Irons Chondrites Carbonaceous Chondrite Achondrite
Barringer’s Crater An iron meteorite 100 feet across and 70,000 tons slamed into the Earth at about 43,000mph in the Arizona desert near Flagstaff 40,000 years ago. Barringer Crater is 4,100 feet wide and 571 feet deep.
Other Impact Craters
Tunguska, 1908
How Much Damage?
Asteroids Apollo Trojans
Ida - Dactyl
Gaspra
Kirkwood Gaps
Asteroids Elsewhere
Sedna