Section 3-5Comets, Asteroids and

Meteors

Objectives

• J.3.5.1. Describe the

characteristics of comets.

• J.3.5.2. Identify where most

asteroids are found.

• J.3.5.3. Explain what meteoroids

are and how they form.

Comets

• Comets are loose

collections of ice,

dust, and rocks

whose orbits are

usually very

eccentric, long,

narrow ellipses.

Objective J.3.5.1

A Comet’s Head• The head of the comet

consists of the nucleus

and the coma.

• The nucleus is the solid

chunk that is revolving

around the Sun.

• The coma is the cloud od

dust and ice that forms

around the nucleus.

Evolution Of A Comet

The Comet’s Tail

• The comet’s tail is the

debris being blown off

the nucleus by solar

wind as the comet

approached the Sun.

• What always pushes the

tail away from the Sun.

• Solar Wind

Comet McNaught In 2007

Comet Lovejoy In 2014

• Comet Lovejoy is fading

now as it has made it’s

way around the Sun

and is heading out into

the Solar System again.

What is the twisting

feature beneath it?

• The Great Wall of China

A Comet’s Tail

• A comet’s tail usually

splits into a gas tail and

a dust tail. The gas tail

will be more influenced

by solar wind and point

more away from the sun

while the dust tail will

be behind the nucleus.

The Origin Of Comets

The Kuiper Belt The Oort Cloud

The Asteroid Belt

• The asteroid belt is

located between the

orbits of Mars and Jupiter.

Most asteroids orbit the

Sun in this belt. Objective J.3.5.2.

Asteroids

Meteroroids

• Meteoroids are chunks of

rock or ice that have broken

off of comets or asteroids

and continue to orbit in the

solar system. Objective J.3.5.3

Meteors• When a meteoroid

enters Earth’s

atmosphere it becomes

a meteor. They appear

as a streak of light

across the sky. Objective

J.3.5.3.

• You might call it a “shooting

star” but it’s not a star at

all.

Meteorites

• Fortunately, most

meteors burn up in the

atmosphere before

they ever hit the

ground.

• If the meteor strikes the

ground, it’s name changes

to meteorite. This is a

name change only.

The Hoba Meteorite

• The Hoba Meteorite is

the largest known

meteorite on Earth as

well as the largest piece

of natural iron on Earth.

• It’s so massive it has

never been moved from

where it was discovered.

Meteor Crater In Arizona

Shoemaker-Levy 9

Shoemaker-Levy 9

Shoemaker-Levy 9

Shoemaker-Levy 9