Comets, Asteroids, and Meteoroids - Keller ISD Schools

Comets, Asteroids,
and Meteoroids

1801
Year Giuseppe Piazzi discovered the first
asteroid, Ceres

4.6
Earth years it takes the asteroid Ceres to travel
around the sun (Ceres – Biggest Asteroid with a
960 km circumference)

2880
Year asteroid 1950 DA will pass close to Earth
– The greatest known impact hazard

Asteroids
Asteroids are small, rocky worlds.
Most asteroids revolve around the
sun between the orbits of Mars
and Jupiter. (asteroid belt)

Asteroids
Earth has been struck many
times in its history by
asteroids.

This 142-million-year-old
crater has a diameter of almost
fourteen miles (twenty-two
km). Like many craters on
Earth, it is misleading. The
raised ring that is clearly
visible to the left is not the
crater rim. It is an erosional
remnant. The remains of the
actual rim are found farther
out from the ring.

•100 km
•212
Million
years old
•Canada

What are they made of?
Type
Composition
Percentage
of Asteroids
Albedo
(reflectivity)
Carbon
(C-type)
Carbon
over 75
percent
0.03-0.09 (Very
dark)
Silicate
(S-type)
Metallic iron mixed with ironsilicates
and magnesium-silicates
17 percent
0.10 -0.22
(Relatively
bright)
Metallic
(M-type)
Iron/ nickel
less than 7
percent
0.10-0.18
(Relatively
bright)
Dark (Dtype)
Water ice/frozen carbon
monoxide mixed with rock
less than 1
percent
0.05 (Relatively
dark and reddish)

Asteroid Ida and the tiny moon Dactyl

Comets
A comet is a
“dirty snowball” about the
size of an earth mountain.
(dirt and ice)
Comets’ orbits are
usually very long, narrow
ellipses.
They produce tails of gas
and dust when they
approach the sun.

Halley’s Comet….
Orbits every 76 years

Halley’s Comet Orbit…
next seen in 2062

Oort Cloud

Comet: Hale-Bopp
www.brainpop.com/science/space/comets/
• Winter and
early spring of
1997
• Next sighting:
4380

Deep Impact colliding with
Temple1

Organic compounds

Meteoroid
A meteoroid is a chunk of rock,
metal, or dust in space.

A Meteor: “A shooting star”
Shooting stars are
not actually stars.
These flashes of light
across the sky are
small bits of rock
burning up in the
Earth’s Atmosphere.

Meteorite
Meteoroids that survive as they
pass through the atmosphere
and hit Earth’s surface are
called meteorites.

http://www.meteorlab.com/METEORLAB2001dev/Open1.htm
There are three major types of
meteorites: stone, iron and
stony-iron.

Barringer Meteor Crater, Arizona
A meteorite can make a hole, or crater, in
the ground when it hits it. The larger the
meteorite, the bigger the hole.

SUMMARY
METEOROID: A piece of stone or metal
that travels in outer space.
METEOR: An object from space that
becomes glowing hot when it passes into
Earth's atmosphere.
METEORITE: A piece of stone or metal
from space that falls to Earth's surface.

Now do this
In your journal, define Asteroid, Comet,
Meteor, Meteoroid, and Meteorite.
Compare and contrast all three using the
Venn Diagram on the board.