Asteroids, meteorites, and comets

ASTEROIDS, METEORITES, AND COMETS

Created by: Jennifer Holloway Grade 5 Teacher Westernport Elementary School

Information for this PowerPoint obtained from: • NSTA Online Module: Solar System: Asteroids, Comets, and Meteorites •NASA •ESA •Windows2Universe.org

This is a meteorite that had been broken off of Mars from a large impact meteorite. It spent millions of years in space before landing in Antarctica.

Meteor Showers and Comets

Common Characteristics of Comets, Meteoroids, and Asteroids  Most are “leftovers” from the formation of

the Solar System.  Most didn’t form into planets themselves, nor were they part of the planets that did form.  Each contains rocky material.

Differences in Comets, Meteoroids, and Asteroids Comets have a great amount of icy material covering them because they are found at the far edge of the Solar System.

Meteoroids are very small rocky bodies that are found mostly near the orbits of planets. In fact, the meteor showers that we observe from Earth’s surface occur as Earth passes through a large concentration of them.

Asteroids contain little icy material and are much larger than comets. Most are found between the orbits of Mars and Jupiter.

Asteroids Was there a missing planet between Mars and Jupiter?

The space between Mars and Jupiter where all of the asteroids are is called the ASTEROID BELT.

Asteroid Belt Location

A Closer Look At Asteroids Eros, the second largest near- Earth asteroid is 33 km long and 13 km wide. Asteroid Belt Motion

Asteroids are objects composed of a combination of metallic and rocky material. One of their defining characteristics is that they are much smaller than

planets.

Barringer Crater (Meteor Crater) Winslow, Arizona

Meteors, Meteorites, Meteoroids The name depends on the location.

Meteoroid-small bits of debris from an asteroid or comet that orbit the Sun.

Meteor-When a meteoroid enters the atmosphere of a planet at high speed and friction causes it to burn up. Meteorite-If the meteoroid does not burn up completely in the atmosphere and collides with the surface. It is the piece that is left.

Comet Debris-Meteor Shower Simulation

The meteorites we find on Earth could have been which of the following? material left over from when the Solar System formed  broken off piece of an asteroid  piece of a star that has died and fallen to Earth  debris trail from a comet  part of a terrestrial planet or the Moon 

What happens to meteors as they fall through Earth's atmosphere?  They fall through the atmosphere without any change in size, mass, or appearance.  They burn up due to friction as they move through the atmosphere at high speeds.  They combine together due to gravity to form larger pieces of debris. They get stuck in the upper part of the atmosphere and never reach the surface.

A Closer Look at Comets

The Mawangdui silk, a 300 B.C. Chinese text of comet observations.

Comet Composition and Size Comets are basically dirty snowballs! Comet Kohoutek

•Rocky Core •Gases condense on the surface and freeze

Comet Hale-Bopp

A Comet’s Orbit What characteristics do comets and asteroids share?

 Both contain rocky material.  Both originate from the edge of the Solar System. Both were formed from planets. Their orbits are much more erratic than planets.

The Life of a Comet See an animation of the life of a comet.

The Kuiper Belt The outer edge of our Solar System is not empty. There are many, many huge spheres of ice and rock out near Pluto's orbit. Astronomers call this huge group of planetoids "Kuiper Belt Objects", or "KBOs" for short. The Kuiper Belt is a bit like the asteroid belt, but much farther from the Sun. See how they are out past Neptune and Pluto?

What might you predict about the formation of asteroids, meteorites, and comets?  Some of them could be the oldest bodies in

the Solar System.  Asteroids, comets, and meteorites did not form around the same time.  They contain material that formed from the planets.  They formed at the same time as the planets.

Flight of a Comet

EPOXI mission has successfully flown by comet Hartley 2.

Mercury's Caloris Basin taken by Mariner 10 in 1974. Image courtesy: NASA/JPL-Caltech.

Densely cratered surface of Mercury as seen by Mariner 10 in 1974. Image courtesy: NASA/JPLCaltech.

Impact craters near Mars' Promethei Terra region (top) and the Acheron Fossae region (bottom). Images courtesy: NASA/JPL-Caltech.

Heavily cratered surface of Mars' polar region. Image courtesy: NASA/JPL-Caltech.

The Mare Oriental region of the Earth's Moon shows several impact craters. Image courtesy: NASA.

The heavily cratered South Pole of the Moon as seen from the Clementine spacecraft. Image courtesy: NASA.

What could’ve created these craters?

Volcanic Processes Comets Meteoroids Asteroids

Meteoroid Hitting the Moon

Click for Video

Collisions With Planets

Mosaic of images showing the evolution of the ShoemakerLevy 9 G (a comet) impact site on Jupiter in 1994. Images not to scale. Image courtesy: NASA/JPL-Caltech/STScI.

Impacting Earth

Clearwater Lakes in Quebec, Canada. Created by an asteroid 290 million years ago.

Wolf Creek crater in Australia. Created by an asteroid impact approximately 300,000 years ago.

Which of the following are characteristics of a meteorite?  found on Earth’s surface after partially burning up in the atmosphere  found between Mars and Jupiter  have erratic orbits that bring them near the Sun  originate in the outer Solar System  composition can be rocky or metallic  a smaller piece of another body such as a planet

Which of the following are the characteristics of an asteroid?  often found between Mars and Jupiter  found on Earth’s surface after partially burning up

in the atmosphere  originate in the outer Solar System  a smaller piece of another body  composition is similar to the terrestrial planets  Have erratic orbits that bring them near the Sun

Which of the following are characteristics of a comet?  found on Earth’s surface after partially

burning up in the atmosphere  often found in the outer Solar System  found between Mars and Jupiter  a smaller piece of another body  have erratic orbits that bring them near the Sun  has an icy cover made of gases also found in the gas giant planets

Summary

Comets are icy bodies composed of rock, dust, and ice. Asteroids are large bodies somewhat similar to planets. Meteoroids are pieces of these larger bodies that have been show to be the oldest bodies in the Solar System.

Assess and Wrap-Up  Quiz  A Meteorite Game