Asteroids, comets, and meteoroids are small rocky or icy bodies that orbit the sun. Thousands of asteroids orbit in the asteroid belt between Mars and Jupiter. Asteroids are remnants of early planet formation. Comets are composed of ice and dust and have highly elliptical orbits, forming tails as they near the sun due to heating. When meteoroids enter Earth's atmosphere, they burn up and are seen as meteors or shooting stars. Those that survive are called meteorites and sometimes leave impact craters. Analysis of meteorites provides clues about early solar system formation and even the origin of life.

1. Vagabonds of the Solar System
Asteroids, Comets, and
Meteoroids

2. A search for a planet between Mars and
Jupiter led to the discovery of asteroids
• Thousands of
asteroids with
diameters ranging
from a few kilometers
up to 1000
kilometers.
• Most orbit within the
asteroid belt
between the orbits of
Mars and Jupiter
• Asteroids are small chunks of ROCK or Metal that
revolve around the sun..

6. The asteroids are the relics of planetesimals
that failed to accrete into a full-sized planet, thanks to
the gravitational effects of Jupiter and other Mars-sized
objects.

7. The sun and Jupiter are keeping the asteroids in
balance because both are pulling in opposite directions.
Jupiter’s gravity helped shape the asteroid belt

8. Often asteroids become CAPTURED because a planet’s
gravity pulls them in orbit.
Jupiter’s gravity captures
asteroids in two locations,
called Lagrangian points,
along Jupiter’s orbit

10. Asteroids occasionally collide with one another,
• causing them to break up into smaller fragments

11. Asteroids are found outside the asteroid belt—
and have struck the Earth
• These outside belt asteroids, called near-Earth objects,
move in highly elliptical orbits that cross the path of
Mars and Earth
• If such an asteroid strikes the Earth, it forms an impact
crater whose diameter depends on both the mass and
the speed of the asteroid

13. An asteroid may have struck the Earth 65 million years
ago, possibly causing the extinction of the dinosaurs
and many other species

14. Comets are a mixture of ice, dust, and a small
amount of rock in the form of a sphere.
Comets move around the sun in highly elliptical
orbits.

16. Comets are hard to find unless they are near
the SUN because…
• As they approach the
sun, the entire comet
vaporizes (Sublimes).
• The temperature
increases due to the
suns solar radiation.
• The nucleus of ice
vaporizes (Solid to a
Gas).
• Solar winds push the
gas and dust away to
form dust and ion tail.

17. PARTS of a COMET
NUCLUES: Center of a
comet made of ice, gas,
and dust
COMA: Thick envelope
of water, CO2, and dust
that melts/sublimes out
of the nucleus.
DUST TAIL: Solid rocky
particles being pushed
away by the sun’s solar
wind.
ION TAIL: Frozen CO2
being vaporized and
pushed away by the
sun’s solar wind.

18. An ion tail and a dust tail extend from the comet, pushed away
from the Sun by the solar wind and radiation pressure

22. Comets formed from left over material during the
formation of the solar system.
• Most comets are found in the Kuiper belt beyond Pluto.
• The Kuiper Belt is part of a vast cloud in near interstelar space
called the Oort Cloud.

24. Halley’s Comet – pt.1 (SD)

25. Comets eventually break apart, and their
fragments give rise to meteor showers
When Earth passes through the tail of a
comet, this is when we typically see
“Shooting Stars”

26. Small rocks in space are called meteoroids
Meteoroids:
– A meteoroid is a
chunk of rock that
is smaller than an
Asteroid.
– Average about 100
m in diameter.
– It is part of an
asteroid or left
over from comet
debris.
– Revolves around
the sun
– Located outside
Earth’s
atmosphere.

27. Meteors – When a meteoroid comes into
contact with Earth’s Atmosphere.
• Meteors burns up
due to the intense
friction of Earth’s
Atmosphere.
• We see a
shooting star in
the sky when this
occurs.

28. Meteorites are meteoroids that go through the entire atmosphere
without burning up completely, making landfall.
(A meteor that makes it through the atmosphere)

29. Meteorites cause craters on Earth Surface

30. Meteorites are classified as stones, stony irons,
or irons, depending on their composition

32. Irons and stony irons are fragments of the core of an asteroid
that was large enough and hot enough to have undergone
chemical differentiation, just like a terrestrial planet

33. Some meteorites retain traces of the early solar system
• Some stony meteorites
come from the crust of
such differentiated
meteorites, while others
are fragments of small
asteroids that never
underwent differentiation
• Rare stony meteorites
called carbonaceous
chondrites may be
relatively unmodified
material from the solar
nebula
• These meteorites often
contain organic material
and may have played a
role in the origin of life on
Earth
• Analysis of isotopes in
certain meteorites suggests
that a nearby supernova may
have triggered the formation
of the solar system 4.56
billion years ago

34. • Fragments of “burned out” comets produce
meteoritic swarms
• A meteor shower is seen when the Earth passes
through a meteoritic swarm