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Solar System Debris: Minor Bodies of the Solar System. Asteroids Comets Meteoroids. ~few hundred miles. sand grain. How big?. Everywhere!. * Where are they?. . . . But concentrated mainly in the:. Main Asteroid Belt Kuiper Belt Oort Cloud. Asteroids. * Debris left-over - PowerPoint PPT Presentation
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Solar System Debris:Minor Bodies of the Solar System
Asteroids
Comets
Meteoroids
Howbig?
~few hundred miles
sandgrain
* Where are they?
Everywhere!
. . . But concentrated mainly in the:
1. Main Asteroid Belt
2. Kuiper Belt
3. Oort Cloud
Asteroids
* Debris left-overfrom solar systemformation!
Average separation 4 million miles
p. 197
Ida & Dactyl
35 mi
Asteroidsviewedfrom Earth
p. 198
Asteroid433 Eros
20 mi
Near-Earth Asteroids: Orbits pass near and/or cross Earth’s orbit.
Asteroid 1994 XM1
Missed Earth by 65,000 mi!
Comets
Kuiper Belt
Kuiper Belt Object(KBO) 1993 SC
4.6 hrs
* KBOs: mainly icy in composition ?
Is Pluto just the largest KBO?
Galaxy
OortCloud
somecomets
originatehere
100,000 AU
p. 203
Many comets orbitwell out of planeof planets’ orbits.
Comet Hyakutake (1996)
~ 50o
Comet Hale-Bopp(1997)
Ion tail: ions energizedby solar photons.
Dust tail: dust particlesscatter (reflect) sunlight.
Nucleus: ice withintermixed ‘gravel.’ .p. 201
March 1, 2001: Hale-Bopp~13 AU from Sun
Comet tails alwayspoint away from the sun.
Solar wind +radiation pressure
p. 202
Nucleus of Comet Halley
“Dirty Snowball”
Comet Borrelly
5 mi
Periodic comets eventually evaporate . . . Some break up near the sun . . .
. . . And some comets dive into the sun.
Meteoroids
* Stuff falls on Earth continuously – most of it harmlessly.
Meteor – streak oflight caused by heating of Meteoroidas it passes throughEarth’s atmosphere.
Meteorite – piece of meteoroid that reaches the ground.
Large meteoroids:chipped from asteroids
Small meteoroids:comet debris
Meteor showers
Leonid Shower(mid-November)
Radiant
Leo
November, 2001
Leonid Storm of Nov 17, 1966
“Thirteen of us, mostly students, drove to observe and record the Leonids atop Kitt Peak on the night of Nov. 16-17, 1966. We formed a circle of chairs and began to study our assigned areas of the sky for meteors. It started off slowly, about 30/hour. After 3 hours it picked up dramatically, and we observed a peak of about 40/second that lasted for 10 to 20 minutes. This was 24,000 in a ten minute period, a rate of 144,000/hour. We stood in awe as the sky seemed filled with meteors.”