minor bodies
TRANSCRIPT
Comets, Meteors, and Asteroids
Structure of a Comet
To Sun
Ion Tail
Dust Tail
Coma
Comet Structure
Nucleus10 km “Dirty Snowball”
ComaCloud of evaporated ices and ionsmay be 100,000 km in diameter
TailAlways points away from Sun
Solar Wind and 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 TapestryNorman 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
Hyakutake
Hale-Bopp
Comet West
The Cause of Meteor Showers
P55/Tempel-Tuttle
Why After Midnight is Best
Rotational Velocity
Orbital Velocity
Midnight
Shower Radiant
The 1833 storm
The 1966 storm
1997 Leonids from Orbit
Two Showers for Halley
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
End of Section