Cosmic Collisions
catalog #3372
Video Production,
Scripts, Teacher’s Guide:
John Colgren
Consultant:
Joseph A. Auer, Jr., SB., M.S.
Planetary Studies Foundation
Elgin, IL
Host and Interview:
Paul Sipiera, A.A., B.A., M.S.
Planetary Studies Foundation
Elgin, IL
Published & Distributed by…
AGC/UNITED LEARNING
1560 Sherman Avenue
Suite 100
Evanston, IL 60201
1-800-323-9084
24-Hour Fax No. 847-328-6706
Website: http://www.agcunitedlearning.com
E-Mail: [email protected]
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Cosmic Collisions
Viewing Time: Part 1 - 16 minutes
Viewing Time: Part 2 - 14 minutes
INTRODUCTION
This video program is intended for use in grades 5 - 9. It may also be
used as a review for high school students. It is divided into two segments. Part One will present material about meteors, asteroids, and
comets. The host is Professor Paul P. Sipiera, geologist and astronomer. Part Two is a discussion by Professor Sipiera about meteorites.
Part One: The Shoemaker-Levy comet that impacted Jupiter in 1994
excited the scientific world and brought new public interest and attention to the subject of cosmic collisions. Our planet also shows the evidence of past collisions, collisions that may very well have caused dramatic changes to the evolution of Earth. Many scientists now believe
that the dinosaur extinction 65 million years ago was the result of a
large impact from either a comet or an asteroid. The Moon and Mercury, as well as other celestial bodies in our solar system, are heavily
cratered.
The atmosphere that surrounds our planet is a constant defense, as
every day millions of meteors stream through the gases and heat up,
burn, and disintegrate from friction. This video explains the difference between meteoroids, meteors, and meteorites. It will also discuss
the asteroid belt and comets that are often forgotten members of our
solar system.
Part Two: This segment concentrates on meteorites as Professor Sipiera
uses the world’s largest private collection of meteorites to describe the
three groups of meteorites and their various qualities.
Paul P. Sipiera is a professor of geology and astronomy at William
Rainey Harper College in Palatine, Illinois. He is associated with the
Schmitt Meteorite Research Group.
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SUMMARY OF THE VIDEO
There are two segments or parts to this program. The first part of the
video describes meteors, asteroids, and comets. It discusses past collisions with our planet and plans to avoid collisions in the future. The
Shoemaker-Levy comet and its impact with Jupiter are used to illustrate the massive power released during such collisions. NASA footage and 3-D computer animations are used to illustrate concepts discussed in the program.
The second part is a discussion about meteorites with Professor Paul
P. Sipiera. Part Two is optional.
You may wish to use these two parts on separate viewing days.
PROGRAM OBJECTIVES
After viewing the video and participating in the various activities, the
students should be able to...
• Explain the significance of the Shoemaker-Levy comet.
• Define terms such as meteoroid, meteor, meteorite, asteroid, comet,
coma, and comet tail.
• Describe the importance of our atmosphere and how essential it is to
protecting us from meteors.
• Describe some of the major cosmic collisions that have happened
over time.
TEACHER PREPARATION
We suggest you view both parts of the video before presenting them to
your students in order to become familiar with the content. Part Two
is optional. You may want to show the interview with Professor Sipiera
as a separate activity on a different day. Then review the blackline
masters that are provided and duplicate those you think will be helpful.
As you review the instructional materials in this program, you may
find it necessary to make some changes, deletions, or additions to fit
the specific needs of your class. Feel free to do so, for only by tailoring
this program to your students will they obtain the maximum instructional benefits afforded by the materials. An answer key for the
blackline masters is provided on page 6 of this guide.
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INTRODUCING THE VIDEO
Most people, and perhaps some of your students, will remember the
exciting visuals and high interest generated by the collision of comet
Shoemaker-Levy and Jupiter in 1994. Before showing the video, you
may want to have a discussion about collisions in space and determine
what students already know about the subject. Ask questions about
the massive cratering of Mercury and the Moon, and see if anyone can
identify why our planet isn’t as cratered. (The Earth’s atmosphere protects us. The gases in the atmosphere create friction as space debris
travels through them. The friction causes the debris to heat up, burn
and, in most cases, disintegrate.)
Present the video. The viewing time is 16 minutes for Part One and
14 minutes for Part Two.
FOLLOW-UP DISCUSSION
Conduct a class discussion after the video presentation using the following questions and answers:
1. Discuss cratering and its significance.
Answer: Cratering (the making of bowl-shaped holes by impact on the surface
of the planets and moons) is something that has continued in our solar system
for billions of years . It was an important and essential part of the formation
of the planets and moons and may even have been responsible for the delivery
of essential material for life as we know it. The water on our planet may be
from comets that collided with the Earth billions of years ago.
2. Why is the Earth's atmosphere so important?
Answer: Every day millions of meteors stream though the gases of our atmosphere, heat up, burn and disintegrate from friction before they are able to hit
the surface.
3. Why is the Moon so cratered?
Answer: The Moon has no atmosphere to burn up space rocks and minerals,
so cratering is widespread. Also, without an atmosphere or water and wind,
there is no weathering, and craters exist unchanged. In fact, the footprints
made by astronauts in 1969 are still there as fresh and untouched as the day
they were made.
4. What is the difference between a meteoroid, meteor, and meteorite?
Answer: A meteoroid is any piece of rock or metal that travels through space,
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a meteor is an a meteoroid that enters the Earth's atmosphere, and a meteorite
is a meteor that makes it through the atmosphere and to the surface of a planet.
4. Define and discuss asteroids, comets, comet tails, and comas.
Answer: Asteroids are large space rocks. They were once thought to be the
remains of an unformed planet between Mars and Jupiter. But that idea is
being challenged because if all the asteroids were combined, they would weigh
only about 1/20th as much as our Moon. Some are tiny, while the largest,
Ceres, is 623 miles in diameter. Asteroids could become moons if they get too
close to a planet.
Comets are objects made from frozen gases, dust, and pieces of rock that orbit
the Sun in very long, narrow orbits. Some comets have short periods and are
found in a belt that stretches from just outside the orbit of Neptune to a few
hundred times the distance from the Earth to the Sun. There are possibly 100
million comets in this belt. Much farther away, at about 50,000 times the
distance between the Earth and the Sun, is the Oort Cloud, which is a giant
cloud of as many as 100 billion comets.
A comet tail is material from the coma that is blown out by the solar wind,
which is a continuous stream of electrically charged particles that flows from
the Sun. The resulting tail always points away from the Sun. There are two
different kinds of tails--a gas tail, which is straight and narrow, and a dust
tail, which is wide and curved.
A coma is the fuzzy glowing ball that forms around the nucleus of a comet. It
grows as the frozen surface of the comet begins to melt. Some tails can grow
more than 100,000 miles across.
5. What is the significance of the Shoemaker-Levy comet?
Answer: The Shoemaker-Levy comet collided with Jupiter in 1994. It gave
scientiest around the world an opportunity to witness the collision of two
celestial bodies. The collision of Jupiter and the comet fragments had been
predicted after a team of astronomers, Eugene Shoemaker, his wife, Carolyn,
and David Levy, identified the comet fragments a year earlier in 1993.
6. Describe some of the major cosmic collisions that have occurred over
time.
Answer: • A women in Alabama who was hit by a nine-pound meteorite;
• A garage and car hit by a baseball-sized meteorite in 1938;
• In 1908, a tremendous explosion that left an entire forest flattened in Russian Siberia. The sound of the explosion was heard 600 miles away, and five
miles away, an entire herd of reindeer were killed. Scientists believe the
destuction was caused by a comet that burned up as it went through the earth's
atmosphere;
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• Many meteorites found in Antarctica;
• Most recently, the Shoemaker-Levy comet.
BLACKLINE MASTERS
Vocabulary Match is a good way to help reinforce the vocabulary
presented in the video. Students are to match the definition at the
bottom of the page with the term at the top of the page.
Path of a Comet is an experiment to demonstrate the elliptical path
of a comet.
Comets is a worksheet with four questions related to the movement
of a comet around the Sun. Students are to use the diagram to help
them answer the questions.
Photographing Meteors is an experiment describing a technique
for photographing meteors. A 35mm camera with a “B” setting and
tripod are required.
Viewing Meteors is an experiment designed to encourage students
to watch for meteors. They must watch the sky steadily for up to thirty
minutes, so comfort is important. A lawn chair set in a reclined position might work well. If they watch steadily for a hour, they may see
as many as ten meteors moving as streaks in the sky. Observations are
best between midnight and dawn.
Crater Formation is an experiment to make observations about the
formation of craters. There are actually three different procedures described. All three experiments use a common marble. One experiment is to see how height affects the crater formation. Another experiment is to see how a marble landing inside a crater changes things.
The third experiment is to see how marbles coming in at an angle are
different from marbles dropped straight down.
Quiz is based on material from Part One of the video program.
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ANSWER KEY
• Vocabulary Match
1. G
2. H
3. D
4. A
5. B
6. J
7. E
8. F
9. I
10. C
• Path Of A Comet
Observations
1. When the tacks are furthest apart, the ellipses look like the path of a
comet.
2. When the tacks are closer together, the orbit will be more circular.
Conclusions
1. Comets take a long time to orbit the Sun, because they are traveling
from the Oort Cloud, which is thousands of times further from the Sun
than our Earth. The comet may have been pulled out of the Oort Cloud
by the gravitational pull of an outer planet. It then is pulled towards
the Sun and swings around it, kicking back to the outer reaches of the
solar system.
2. For most of the trip a comet is not visible because it reflects light. It
doesn’t give off its own light. The huge coma and tail form only during the time the comet is near the Sun.
• Comets
1. The path of a comet is in the shape of an ellipse.
2. The comet would be brightest during the time it is closest to the Sun.
3. The tail of the comet is material from the coma that is blown out by
the solar wind. The solar wind is made up of particles that are given
off by the Sun.
4. Comets lose material because every time they pass the Sun some of
the frozen material they are made of is heated and blown off.
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• Photographing Meteors
The photographs should look like swirling spirals. Because of the rotation of the Earth, the stars will seem to have formed these spirals.
Meteors will look like streaks rather than spirals. If photographs come
out light or foggy, the exposure time may have been too long.
• Viewing Meteors
Meteors don’t last long. It only takes a few seconds for them to streak
across the sky. That’s why you have to be looking for an extended
period of time. Ancient people thought meteors were falling stars because these were little spots of light streaking across the sky.
• Crater Formation
Observations:
1. The higher the marble is dropped, the larger the crater.
2. Craters inside craters are interesting because of the upheaval of debris.
3. The material thrown out of the crater will be a giveaway for determining the angle of a meteor. Much of the material from the crater will
land out of the crater in the direction opposite the meteor’s impact.
• Quiz
1. A meteoroid is any particle in space.
A meteor is the name given to a rock or particle that speeds through
the atmosphere.
A meteorite is the name given to a meteor that gets through the atmosphere and makes contact with the surface of the Earth.
2. A nucleus is the center of a comet made up of frozen dirt, dust and
gas.
A coma is the fuzzy glowing ball that forms around the nucleus of a
comet.
A tail is made up of glowing material that is blown out of the coma by
particles in the solar wind.
3. Scientists have found evidence that 65 million years ago, a meteorite or comet struck the Earth causing drastic changes. Many species of
animals and plants died off. The dinosaurs were among the casualties.
The evidence for this occurance is a thin layer of iridium found in the
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fossil record. Iridium is rare on Earth but common to asteroids.
4. Asteroids are found in orbit between Mars and Jupiter. Some of the
asteroids are as big as a state, while some are much much smaller. They
can bump into each other causing one or the other to change orbit.
Also, the gravitational attraction of planets may cause an asteroid to
change its path.
5. The Moon has no atmosphere and therefore no protection from meteoroids. Also without an atmosphere and water, the craters remain
untouched by weathering.
6. The Earth has an atmosphere that protects our planet. As meteors
enter the atmosphere, they heat up and burn. Few will get through to
reach the surface. Craters on Earth don’t last long because of weathering. The wind and water will erode away the crater.
PART 2
INTERVIEW AND DISCUSSION WITH PROFESSOR SIPIERA
PART 2 is an optional video to be used at the teacher's discretion.
Professor Sipiera discusses three types of meteorites: iron, stony iron
and stony. The iron meteorites consist of approximetaly 92% iron,
whereas stony irons consist of approximately 50% of the metals iron
and nickel. Stony meteorites consist of smaller percentages of iron
and nickel along with other substances.
Professor Sipiera points out what to look for when identifying a meteorite. If you suspect a stone to be a meteorite, see if it's attracted to a
magnet. Inspect it for a blackened surface. Based on these results, do
a chemical analysis for nickel and iron.
Some interesting highlights from the video are:
1. Stony iron meteorites were used by Indians in the 1800s to make
arrowheads.
2. Most meteorites have fallen to Earth in remote areas.
3. Magnets are attracted to most meteorites, whereas most stones on
Earth are not attracted to a magnet.
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4. The shape of freshly-fallen meteorites gave space engineers the idea
for a deflector to be used on spacecraft reentering the Earth's atmosphere.
5. Some meteorites on Earth have been dated back as far as 4.61 billion
years. They are believed to be the oldest solid materials in our solar
system.
6. Diamonds have been found in meteorites formed during the death
of red giant stars that are older than our Sun. The meteorites, sometimes referred to as the Rosetta Stone of our solar system, can give us
evidence of the formation process of our planet.
7. There are water molecules in some meteorites. This provides us
with evidence of water as we know it that exists in space.
8. The Beringer meteorite crater in Arizona is large enough for three
million people to see a football game.
9. The astronauts who have visited the Earth's Moon found only a few
meteorites because the meteorites vaporized upon impact with the
surface of the Moon. The same is true with those meteorites which
have made contact with the Earth.
It is suggested that you carry on a discussion with your class that is
appropriate to the level of your students. The above informational
points may be helpful in your discussion.
The interview with Professor Sipiera may also be used as a resource
for student projects.
Script of Video Presentation
In 1994 scientists around the world watched as pieces from a disintegrated comet smashed into Jupiter. This was a great opportunity for
scientists to witness the collision of two celestial bodies. The collision
of Jupiter and the comet fragments had been predicted after a team of
astronomers identified the comet fragments a year earlier.
Eugene Shoemaker, his wife Carolyn, and David H. Levy took photographs of the night sky in March of 1993. Carolyn Shoemaker noticed
what she referred to as a squashed comet in one of the photographs.
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They contacted Jim Scotti at the Kitt Peak National Astronomical Observatory in Arizona, and he verified what they had observed. They
were looking at fragments of a comet that, on its last passage through
this part of the solar system, must have been torn apart.
Twenty large fragments impacted Jupiter at speeds of 37 miles per second. The largest fragments were over one mile in diameter and created disturbances in Jupiter’s atmosphere that lasted for months.
The results of the collisions will be studied for years, but one thing is
very apparent: the fragments created quite a stir on Jupiter. One of the
fragments made an explosion the size of the Earth.
What is the likelihood that a similar collision could happen on Earth?
Well, the answer is that it has. There is evidence all around the world
that our planet has been hit by large asteroids and comets at various
times throughout history. In fact, every single day an average of 20
million pieces of space debris make contact with our atmosphere.
Twenty million is an awfully large number (Professor Paul Sipiera explains the million book).
Most of the space garbage that makes contact with our atmosphere is
smaller than a grain of sand. Some of the rocks and metals that get
into our atmosphere are bigger but are burned and disintegrate before
they reach the surface. If they are large enough, they may be visible.
They are seen as streaks of light cutting across the sky. People refer to
them as “falling stars,” but they are really just pieces of rock or dust
burning up in the Earth’s atmosphere.
A meteoroid is any piece of rock or metal that is traveling through
space. If the meteoroid enters the Earth’s atmosphere, it is referred to
as a meteor. If the meteor travels through the atmosphere without
burning up and makes it to the surface of the planet, it is called a meteorite.
Most meteors burn up in the atmosphere because they can be speeding along at as much as 150,000 miles per hour. This is an incredibly
fast speed. At that speed, it would be possible to travel across the
United States in just over one minute. So when meteors traveling at
exremely fast speeds make contact with the gases of the Earth’s atmosphere, they heat up because of friction.
Friction is caused when two objects rub together. One of the products
of friction is heat. Just rub your hands together briskly for a few sec-
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onds, and you can experience that heat. The meteor heats up, glows
and burns. In most cases, it will be completely destroyed by friction.
However, every year about 500 meteorites may reach the Earth. Most
of these land in the oceans or in out-of-the-way places. Only about 150
meteorites hit the land. They range in size from pebbles to huge boulders. The largest ones can weigh many tons.
In Antarctica, scientists have found many meteorites. Meteroites found
in Antartica are among the best preserved because of the cold, dry climate. Several thousand meteorites have been found in Antarctica. They
are easy to spot against the snow- and ice-covered surface. One type
of meteorite seems to have come from Mars. It is possible that an asteroid crashed into Mars millions of years ago causing material from
that planet to be kicked into space. Now, millions of years later, a fragment from the surface of Mars may have landed in Antarctica.
Some other interesting meteorites contain organic matter, which means
that at least some of the substances on which life is based also exist in
space.
It might be hard to imagine the Earth being hit by meteorites, but all
you have to do is look at our closest neighbor, the Moon. The Moon is
heavily cratered. It has no atmosphere to protect it from meteoroids,
and without an atmosphere, it has no weather or water. Therefore,
things on the surface of the Moon stay pretty much the same. There is
no eroding or weathering from wind or water, so imprints remain. Even
the footprints made by astronauts over twenty-five years ago are still
as fresh as the day they were made.
The Earth is much larger than the Moon, so it is actually a bigger target
than the Moon. Therefore, more meteoroids make contact with the
Earth than the Moon. Our atmosphere protects us, but there is evidence of large impacts on Earth.
There are about 70 huge craters found throughout the world. One of
the most famous craters is in Arizona, near Winslow. This crater is
three-quarters of a mile across and was made within the past 50,000
years. The majority of the meteorite that made it was never found;
most of it disintegrated on impact. It was estimated to have been about
90 feet across and made up of iron and nickel.
The question may arise as to the chances of being hit by a meteorite. It
is felt that meteorites hit humans only once in 10,000 years. There is
only one known person to have been hit by a meteorite. A woman in
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Alabama was bruised when a nine-pound meteorite tore through the
roof of her house, hit a radio, and then hit her.
This is an exhibit that has been on display in the Field Museum of
Natural History in Chicago for years. It shows the sequence of events
that occurred in 1938 when a small baseball-sized meteorite hit a garage. It went through the roof of the garage and continued through
the roof of the Model T Ford that was parked in the garage at that time.
It went through the steel roof and through the car seat and floor. It
came to rest on the muffler under the car.
On June 30, 1908 in Russian Siberia, there was a tremendous explosion
that left an entire forest flattened. The sound of the explosion was
heard 600 miles away. Five miles away an entire herd of reindeer was
killed. Scientists believe that this tremendous destruction was caused
by a meteorite or comet that burned up as it went through the Earth’s
atmosphere. Fortunately this happened far from a populated area.
Many scientists believe that dinosaurs died out as a result of a collision
that may have occurred 65 million years ago.
Traces of an element called iridium seem to suggest that a comet or
meteorite of considerable size struck the Earth. Iridium is commonly
found in meteorites. It does occur on Earth but mostly near the core of
the planet. Iridium traces were found in Siberia at the site of that huge
explosion in 1908.
Scientists have also found a thin layer of iridium in the Earth’s fossil
record. It dates back to the time of global extinction all over the Earth.
Sixty- five million years ago, many species of plants and animals suddenly died out, just like the dinosaurs. Scientists believe that possibly
a comet or meteorite exploded in the atmosphere or actually struck the
surface of the planet. This explosion could have thrown huge amounts
of matter into the atmosphere causing a virtual blackout. Sunlight
couldn’t get through and plants and animals died as a result.
So where did asteroids, meteors, and comets come from? Scientists
believe our solar system formed over 4.5 billion years ago as clouds of
gas and dust began to form what would become the sun, planets and
the moons. Some of the leftover material orbits the Sun in the asteroid
belt between Mars and Jupiter.
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Asteroids are large space rocks. They were once thought to be the
remains of an unformed planet that lies between the orbits of Mars
and Jupiter. But that idea is being challenged, because if all the asteroids were combined, they would weigh only about 1/20th as much as
our Moon.
So far, 2,500 asteroids have been identified. Some are very small, and
the largest, Ceres, is 623 miles in diameter. It weighs as much as all the
other asteroids combined. Asteroids could become moons of various
planets if they get too close to a planet. The two moons of Mars, called
Phobos and Deimos, are thought to have been asteroids before being
captured by Mars’ gravitational pull.
Comets are objects made of frozen gases, dust and pieces of rock that
orbit the sun in elliptical orbits. Some comets have short periods and
are found in a belt that stretches from just outside the orbit of Neptune
to a few hundred times the distance from the Earth to the Sun. There
are possibly 100 million comets in this belt. The Hubble Space Telescope has just recently been used to spot a few of the larger comets in
this belt.
Much farther away, at about 50,000 times the distance between the Earth
and the Sun, is the Oort Cloud. This is a gigantic cloud of as many as
100 billion comets. A round trip orbit for these comets may take thousands of years. Collision between comets cause some to move inward
toward the Sun while others are bumped out of our solar system entirely.
Comets are made up of a nucleus which is the tiny solid part of the
comet. This is a dirty snowball of bits of rock and dust frozen in ice.
As the comet approaches the Sun, the heat from the Sun begins to vaporize some of the material that makes up the comet.
A coma is the fuzzy glowing ball that forms around the nucleus and
can grow to be more than 100,000 miles across.
The tail forms when solar wind from the Sun strikes the comet The
solar wind is a continuous stream of electrically-charged particles that
flow from the Sun. Because material is being blown away from the
comet by the solar wind, the resulting tail always points away from
the Sun, and can be millions of miles long. There are two different
kinds of tails that can form. A gas tail is straight and narrow. A dust
tail is wide and curved.
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Throughout history people have been interested in comets. In ancient
times comets were believed to be the bearers of doom and bad luck.
People were terrified by them. Today many scientists believe that it
might have been comets that brought life to our planet in the first place.
It is very possible that some of the water on Earth is actually from
comets billions of years ago.
There have been near misses recorded by NASA over the past few years.
For instance, in 1992, the asteroid Toutalis passed within 2.2 million
miles from Earth. In 1991, a smaller asteroid came within 106,000
miles of Earth. This is less than half the distance between the Earth
and the Moon!
So what are the chances that our planet will be struck again by a comet
or asteroid large enough to cause mass extinction? Some scientists
believe that such a collision could occur once every million years.
Is there something we could do to protect our planet? Scientists have
considered some possible solutions. One would involve intercepting
the incoming asteroid with a nuclear warhead. The bomb would be
detonated to one side of the asteroid, and the resulting explosion would
cause it to change course. Perhaps this is not the best idea since blowing up the asteroid would only make more projectiles.
We can be thankful that our planet has an atmosphere that can protect
us against most meteoroids. Without the protection, the Earth would
look like the Moon or Mercury. We should definitely keep an eye on
the comets and asteroids that come sweeping past our orbit around
the Sun. A big collision could cause devastating changes on Earth, and
it has in the past.
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