Chapter 16 Section 5

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Chapter 16 Section 5

• Comets, Asteroids, and Meteors

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Ch16 S5 Essential Questions

• What are the characteristics of comets?
• Where are most asteroids found?
• 3. What are meteoroids and how do they form?

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Comets

• Farther our in space, near the edge of the solar
  system a huge cloud formed.
• This cloud is believed by some astronomers to be
  the home of comets.

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Minor Members of the Solar System

• A comet orbits the sun. A comet is made up of
  ice, dust, and small rocky particles. You can
  think of a comet as a dirty snowball.
• Comets are small bodies made of rocky and
  metallic pieces held together by frozen gases.
  Comets generally revolve about the sun in
  elongated orbits.
• Comets are loose collections of ice, dust, and
  small rocky particles whose orbits are usually
  very long, narrow ellipses.

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Minor Members of the Solar System
? Coma
The brightest part of a comet is the head. A
comets head is made up of a nucleus and a coma.
The nucleus is the solid core of a comet. The
coma is a fuzzy outer layer made up of clouds of
gas and dust.
A small glowing nucleus with a diameter of
only a few kilometers can sometimes be detected
within a coma. As comets approach the sun, some,
but not all, develop a tail that extends for
millions of kilometers.
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Minor Members of the Solar System
? Kuiper Belt
Like the asteroids in the inner solar system,
most Kuiper belt comets move in nearly circular
orbits that lie roughly in the same plane as the
planets.
? Oort Cloud
Comets with long orbital periods appear to be
distributed in all directions from the sun,
forming a spherical shell around the solar system
called the Oort cloud.
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Minor Members of the Solar System
? Halleys Comet
The most famous short-period comet is Halleys
comet. Its orbital period is 76 years.
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Comets Tail Points Away from the Sun
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Asteroid Belt

• Most asteroids revolve around the sun between the
  orbits of Mars and Jupiter.
• An asteroid is a rocky object that orbits the
  sun. Asteroids are too small to be planets.
• Most asteroids are in orbit between Mars and
  Jupiter. This region of the solar system is
  called the asteroid belt.
• They have orbital periods of three to six years.

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• Most asteroids are less than 1 kilometer in
  diameter. Some are much larger.
• Scientists think that asteroids are leftover
  pieces of rock from the early solar system.

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Irregular Orbits of Asteroids
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Meteors

• Meteoroids come from comets or asteroids.
• A meteoroid is a chunk of rock or dust in space.
• Some meteoroids form when asteroids crash into
  each other. Other meteoroids form when comets
  break apart.

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• Meteoroids can enter Earths atmosphere. When one
  does, friction between the meteoroid and the air
  produces a streak of light in the sky. A meteor
  is a streak of light in the night sky produced by
  a meteoroid. (popularly called a shooting star)
• Most meteoroids burn up completely in Earths
  atmosphere. However, some hit Earths surface.
  Meteoroids that hit Earths surface are called
  meteorites.

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Minor Members of the Solar System

• Most meteoroids originate from any one of the
  following three sources
• interplanetary debris that was not
  gravitationally swept up by the planets during
  the formation of the solar system,
• material from the asteroid belt, or
• the solid remains of comets that once traveled
  near Earths orbit.

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Major Meteor Showers
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Ch16 S5 Essential Questions
video

• What are the characteristics of comets?
• Like a dirty snowball.
• Nucleus center solid part of the comet
• Coma fuzzy cloud of vaporized gases around the
  nucleus
• Tail stream of dust and gases always points
  away from sun
• Where are most asteroids found?
• Between the orbits of Mars and Jupiter in the
  asteroid belt
• What are meteoroids and how do they form?
• A chunk of rock or dust in space
• Form when asteroids collide in space or when
  comets break apart