COMETS, ASTEROIDS, AND

METEORS

COMETS

A small clump of ice and dust with an

extremely elliptical (oval) orbit around

the Sun.

As it nears the sun on it’s orbit, the ice

sublimates (goes straight from a solid to a

gas) and forms the coma and tail.

The comet becomes visible because the

gas gets into an excited state and lights

up (kind of like neon lights)

COMET ANATOMY

3 parts:

Nucleus

Coma

Tail: always points away from sun

PARTS EXPLAINED

Nucleus – mass of ice and frozen gas

Coma – cloud of gas that surrounds

the nucleus

Tail – formed when the comet travels

near the sun; it’s the nucleus vaporizing

COMETS

HUBBLE DETAILS AN INCREDIBLE

COMET:

This is a picture of

comet 73P breaking up

as it is passing by the

Sun.

The comet was 1.17 AU

from the sun and .22

AU from Earth.

Photo credit: NSA, ESA,

STSci

WHERE COMETS COME FROM…

Short period comets reside in

the Kuiper Belt

Long period comets reside in

the Oort Cloud

In 1994, Comet Shoemaker-Levy 9

collided with Jupiter.

ASTEROIDS

A rocky object revolving around the sun

It is smaller than a planet (this is what

makes it different from terrestrial/rocky

planets).

They are found between the orbits of Mars

and Jupiter in the Asteroid Belt!

ASTEROIDS

Description: Rocky remains from the

formation of the solar system

Composition: Rock and iron

Notable Asteroids:

Ceres – now a dwarf planet, only one in

the asteroid belt

Vesta – can be seen without a telescope

ASTEROIDS

Size: Varies from a few hundred feet to a

few hundred miles

Jupiter’s relationship with asteroids:

Scientists believe the asteroid belt is the

remains of a planet that never formed

because of Jupiter’s gravity

Evidence asteroids have hit planets:

Impact craters like the one thought to

have caused the dinosaur extinction

ASTEROIDS

METEORS

Description: Rocky or metal debris in

space; most no bigger than a pebble

Meteoroid: a small chunk of rock or dust in

space

Meteor: a streak of light in the sky

produced by the burning of a meteoroid

in Earth’s atmosphere

Meteorite: a meteoroid that has hit Earth’s

surface

THE LIFE OF A METEOR…

Please draw

something similar to

the image on the right

in your notes sheet.

At each stage, write a

short description of

what is happening

that is making it

“change” and label

each stage

Atmosphere

Earth’s Surface

METEOROIDS

Meteoroids are small chunks of rock and

dust left over from asteroids and comets

that pass by the Earth.

Composition: rocky, iron, or mixed

Location/orbit: Found within the path of

the Earth’s orbit around the sun.

METEORS

3 types:

Meteor: a streak of light in the sky produced by

the burning of a meteoroid in Earth’s atmosphere

Meteoroid: a chunk of rock or dust in space

Meteorite: a meteoroid that has hit Earth’s

surface

Meteor Impact Crater in

Arizona.

COMETS VS. METEORS (WHAT’S THE DIFFERENCE?)

If both look like bright streaks of light in the sky,

how can you tell the difference?

Comets seemingly hang motionless in the sky

whereas meteors quickly streak across the sky

(shooting star) and are only seen for a fraction

of a second

Comets are millions of miles away, meteors

are in our atmosphere.

Comets are orbiting the sun, Meteors are

headed towards the Earth’s surface.