Chapter 8 - Vagabonds of the Solar System

Asteroids - chunks of rock and metal called planetesimals (these  collide to form planets)


Asteroid Threat?

Most orbit between Mars and Jupiter ( 2 - 3.5 AU) called the asteroid belt

Piazzi (1801) - discovers first Ceres - (patron goddess of Sicily) accounts for 30% of the know mass of ALL asteroids

Kirkwood gaps - caused by resonance with Jupiter’s gravity

Lagrange Points - stable orbits between two gravitational sources

Trojan Asteroids - in Jupiter’s Lagrangian points; one in front, one trailing


Amor - cross Mars’ orbit

Apollo & Atens - cross Earth’s orbit



COMETS - Long Haired Stars

More of Jerry Lodriguss' work check out his gallery

Head - small, bright area at front

Tail - always faces away from sun, can extend 30o across the sky and is brightest at perihelion


Upon closer inspection

Head is composed of
coma - heated gas which surrounds the
nucleus - the small center (dirty snowball)


Tail - is in reality two

dust - left behind and curves smoothly

gas or ion - ions blow straight back by the solar wind

Where do they come from?

The Oort Cloud - 50,000 AU

(Copyright 1997 Dr. Sten Odenwald) From Ask the Astronomer

Halley’s (Haw - le) - periodic


Kupier Belt Objects (KBOs)

 "Quaoar" (pronounced kwa-whar) after a Native American god.


Meteoroids - in space

Meteor - “falling star” burning up in the atmosphere

Meteorite - when it hits the ground

most are micrometeorites <1mm, ~ 100 tons a day

                        Seen Falling       Finds
Irons                 6%                     66%
Stony-irons        2%                     8%
Stones              92%                    26%

 Widmanstätten pattern


Meteor Showers - when we pass through the orbital debris of comets - they seem to come from one direction called the radiant.

Chp 8 - Asteroids & #