Meteoroids, Asteroids, and Comets

I. Asteroids

a. Asteroid

i. Small, irregular shaped objects

ii. Revolve around the sun

iii. Vesta: Brightest

1. can be seen with a telescope

b. Asteroid belt

i. Orbit between Mars and Jupiter

1. consists of lots of asteroids

ii. Unformed planet?

1. Jupiter’s gravity wouldn’t let planet form

c. Other Asteroids

i. Apollo Asteroids

1. Earth-crossing asteroids

ii. Trojan Asteroids

1. travel with Jupiter in its orbit

iii. Craters

1. when asteroids hit the surface

iv. Dinosaurs

1. asteroids impact ~65mya killed them

II. Meteoroids

a. Meteoroid

i. Chunk of rock/metal, smaller than an asteroid, orbits the Sun

b. Meteor

i. A meteoroid that has entered the atmosphere

ii. “Shooting star”

1. Glow from meteor heating up in the atmosphere

2. caused by friction

iii. Meteor Shower

1. an orbit of meteoroids in Earth’s orbit

2. Results in a “shower” of lights

c. Meteorites

i. A piece of a meteoroid that reaches Earth surface

ii. Two Types

1. iron and nickel

2. stone and iron

iii. Biggest Earth Crater from impact

1. 174 m deep; 1,219 m across

III. Comets

a. Comet

i. Icy object traveling around the Sun

ii. Over 2,000 in our Solar System

iii. Form beyond Pluto

1. Oort Cloud

iv. Irregular orbits

b. Orbits of comets

i. Travel in fixed orbits around the Sun

ii. Some get to close to the Sun

1. Burn up

iii. Some never return, other approach every so many years

iv. Tail

1. forms as orbit gets close to Sun

2. forms because ice center is evaporating