EXPLORING SPACE: OUR SOLAR SYSTEM

EXPLORING SPACE: OUR SOLAR SYSTEM Teacher's Guide Video Production, Scripts, Teacher s Guide: John Colgren Footage Provided By: NASA Lyndon B. Johnson Space Center Media Services Branch Houston, Texas Published and Distributed by AGC/UNITED LEARNING 1560 Sherman Avenue Suite 100 Evanston, Illinois 60201 1-800-323-9084 24-Hour Fax No. 847-328-6706 Website: http://www.agcunitedlearning.com E-Mail: info@agcunited.com

Space Exploration: Our Solar System Grade Level: 5-8 Viewing Time: Part 1-20 minutes Part 2-11 minutes INTRODUCTION This video production is divided into two parts which are each contained on one videotape. The first part is about the origin of our solar system, the sun, and the first four planets. The second part covers the remaining five planets. NASA footage is used throughout each part to highlight the key ideas and concepts presented. PROGRAM OBJECTIVES After viewing the video and participating in the various activities, students should be able to... Identify specific characteristics of each of the planets in our solar system. Describe the beginning of our solar system. Describe the make-up of the sun. Define plate tectonics. SUMMARY OF THE VIDEO The first part of the video uses computer-generated animation to illustrate how scientists believe the solar system evolved. Then information about the sun and the four inner planets is presented. NASA footage from satellites and unmanned landers is used to describe the conditions found on each planet. For example the Greenhouse Effect found on Venus is described and related to Earth. Also plate tectonics is presented as an explanation of Earth s continuing change. 1

The second part of the video program is devoted to the asteroids and the outer planets. TEACHER PREPARATION We suggest you view the video before you present it to your students in order to become familiar with its content. 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 in this guide. INTRODUCING THE VIDEO It is suggested that the video not be shown during one sitting. The material has been divided into two parts for a reason. There is a lot of information to be shared in this production, so use the video on two separate viewing days. PART ONE: The Inner Planets-20 minutes Survey the class to see what they may already know about the solar system. Ask questions such as... What is a solar system? When did our solar system begin? What are some of the things found in our solar system? How have we learned about the other planets in our solar system? Show the first part of the video program. PART TWO: The Outer Planets- 11 minutes The second part is about the asteroids and the outer planets. The outer planets are called gas giants because of their incredible size and gas composition. Pluto is the oddball 2

of the solar system. Stuck out with the gas giants, Pluto is more like the solid hard-core inner planets. BLACKLINE MASTERS Planets In Our Solar System, Pages 1 and 2 are designed to share information about basic facts about the planets in our solar system. Students will use the first page as a reference as they answer questions found on the second page. Before using the two pages be sure to discuss the meaning of the terms rotation and revolution. The rotation of a planet is the time it takes to spin once around an imaginary axis that goes through the planet. Revolution refers to the time it takes a planet to orbit the sun once. Mass - Gravity - Weight is a worksheet designed to show what individuals would weigh on other planets, the moon, or the sun. Students will use provided fractions or mixed numerals to calculate their weight on other worlds. Solar Bingo, Pages 1 and 2 are intended to be used together. Students use page 1 to create their own personalized playing card. They place the boldfaced terms in the sixteen empty squares of their playing card. The words can be placed anywhere and in any order on the card. The read cards on the second page should be cut out and used as draw cards once everyone is ready to play. One person will shuffle the read cards and then the top one is selected and read. Everyone decides what word on their card fits the definition on the read card. Then everyone uses a corn kernel, scrap of paper, or something small to mark that word on their card. The first one to fill a row horizontally, vertically, or four across diagonally is the winner. Solar System Model gives directions for setting up a scale model of the solar system using one inch equals one million miles. This activity should really help students appreciate the size of the solar system. 3

FOLLOW-UP DISCUSSION The following are suggestions for discussion following the video presentation. The planet Venus is suffering from what is known as the greenhouse effect. This condition is causing temperatures on Venus to soar. Venus has the hottest temperatures in our solar system brought on by the blanketing effect caused by the thick clouds that surround the planet. The clouds let energy from the sun in and then when this energy strikes the surface of the planet, instead of bouncing back into space, it is caught and held by the blanket effect of the clouds. Scientists are concerned that the greenhouse effect might happen on earth as more and more gasses are produced and released into the atmosphere by our industrialized nations. How would life on this planet be affected if the greenhouse effect does raise the climatic temperatures of earth? Discuss the idea that earth is an ever-changing planet. It is constantly being changed by erosion, volcanic eruptions, and plate tectonics. Look at globes and wall maps to see evidence of plate tectonics. India is on a plate that was once near the southwest side of Africa. For millions of years India has been going under the Asian plate causing the build up of the Himalayan mountains. Look at California which is on the Pacific Plate. It has been shifting as it moves against the North American Plate. How are the inner planets different from the outer planets? ANSWER KEY PLANETS IN OUR SOLAR SYSTEM 1. Venus 2. Venus 3. 84 earth years 4. 2,800,000,000 - two billion, eight hundred million miles 5. Jupiter 4

6. 24,575 7. Mars 8. b 9. b 10. a MASS - GRAVITY - WEIGHT Answers will vary. 3. The nine planets in our solar system revolve around the Sun because it has the greatest mass and, therefore, the strongest gravitational attraction. SOLAR BINGO Sun - the center of our solar system. Mercury - the closest planet to our sun. Venus - the hottest planet. Earth - 93,000,000 miles from the sun. Moon- the natural satellite of earth. Mars - this planet has the largest volcano known. Asteroids - these are found between Mars and Jupiter. Jupiter - this planet has a storm that has been raging for hundreds of years. Vacuum - the emptiness of space. Saturn - the ring system of this planet is the largest in the solar system. Uranus - a planet about the size of Neptune. Neptune - trades places with Pluto as furthest planet from the sun. Pluto - this planet has a moon which is half its size. Orbit - Planets revolve around the sun in an. Axis - the imaginary line through the center of a planet, moon, or star. Gravity - the pull towards the center of any object. SOLAR SYSTEM MODEL This is an information sheet that provides directions for constructing a model of the solar system. 5

VIDEO NARRATION SPACE EXPLORATION: OUR SOLAR SYSTEM Nearly five billion years ago our solar system began to form. It started as a huge cloud of dust and gas. This dust and gas began to collect in the center of this cloud. The cloud was spinning and the gravity caused the cloud to break apart. As more and more of this material came together, the temperature rose. As it became hot enough, a nuclear reaction began. The sun was born. Most of the material of the original cloud had formed the sun, but there was some dust and gas left that collected to form the planets, moons, comets, and asteroids of our solar system. It took about 100 million years for our solar system to form. This videotape will explore the nine planets of our solar system. It will discuss their characteristics, positions, sizes, and composition. Over the last few years, much has been learned about our neighbors and the center of it all, the sun. In fact, the center of the solar system is a good place to begin. The sun is the largest object in our solar system. It could easily hold one million earths. In fact, 98% of all the material of our solar system is inside the sun. Our sun's gravity keeps all the other objects in the solar system in regular orbits. For as huge as our sun seems to be, it is actually only an average-sized star. When we look into the night sky, we can see thousands of twinkling stars. They seem so very small to us because they are very, very far away. The distances are so great that they are not measured in miles but in light-years. What is a light-year? It sounds like a measurement of time, but it is a measurement of distance. It is the distance light travels in one year. Light travels at the incredible speed of 186,000 miles per second, which is like traveling from New York to San Fransico sixty-two times in one second. So to calculate the number of miles in a light-year, you must 6

figure out how many seconds there are in a year and multiply that number by 186,000. This number is close to six trillion, which is a very big number, especially when you consider one trillion is a million million. About the only person that can relate to those numbers wears clown shoes and sells hamburgers. Well anyway, the closest star to our planet, other than the sun, is 4.3 light-years away. That means it takes 4.3 years for the light from that star to reach us. In space, the distances are beyond imagination. But let's return home to our sun and its planets that make up our solar system. Our sun is just one of the one hundred billion stars in our galaxy called the Milky Way Galaxy. Our solar system is far from the center of this huge galaxy. The sun is made up of layers. The sun's energy is created in its center called the core. Temperatures in the core are estimated to be 27 million degrees Fahrenheit. This tremendous heat and pressure fuse, or combine, hydrogen atoms, changing them into helium atoms. This process is called nuclear fusion and an enormous amount of energy is released. The energy moves through the radiation zone and then the convection zone where it finally reaches the surface, which is called the photosphere. The temperature at this level is about 10,000 degrees Fahrenheit. The sun's atmosphere has two layers called the chromosphere and the corona. Energy from the core rises through the layers and is released into space as heat and light. People throughout history have realized the importance of the sun to life on earth. Without the sun's heat and light, life as we know it would be impossible. Early people worshipped the sun and some civilizations even treated the sun as a god. Scientists estimate that the sun has been active for about 4.5 billion years. Stars, like so many other things in the universe, go through a life. They are born, are active for 7

billions of years, and then die. Our star, the sun, is probably going to be active for another 4.5 billion years and and then it will go through changes. It will expand as a red giant. It will become so large that it will reach the orbit of the earth. Then it will shrink to an object no larger than the earth. There are nine planets in our solar system. They are usually divided into two groups: The inner and outer planets. The four planets that make up the inner planets have some common traits. They all have cores made up of iron and rocky surfaces. They are called terrestrial, which means earth-like. They are small planets. All four inner planets were bombarded by meteorites which cratered their surfaces. Mercury and Mars still show the signs of this massive cratering but Earth and Venus have weather conditions that have erased the evidence of this cratering activity. The outer planets are very far from the sun and are called gas giants. The only exception is tiny Pluto, which is grouped with the outer planets even though it is unlike them. Lets look at the inner planets first. Mercury is the closest planet to the sun. It is the second smallest planet and is only slightly larger than our moon. The iron core of Mercury is very large which makes it almost as heavy as Earth. Temperatures on Mercury are severe. The side facing the sun can reach 800 degrees Fahrenheit, and the side in darkness can reach -292 degrees Fahrenheit. One reason for such a wide range of temperature extremes is due to the fact that Mercury has no atmosphere. Without an atmosphere, heat from the sun can't be held. The planet takes 89 earth days to go around the sun, which is its year. The strange thing is that Mercury rotates on its axis very slowly. It takes 59 days to spin around once, which would be a Mercury day. 8

We know a lot about Mercury because of spacecraft sent to orbit it. Mariner 10 was launched in 1973 and photographed much of Mercury's surface. The second planet from the sun is Venus. It is often called Earth's sister planet, because they are both about the same size. Venus is the closest planet to Earth. Venus has a very thick atmosphere that works like a series of blankets trapping the sun's heat, causing temperatures of around 840 degrees Fahrenheit. Carbon dioxide makes up most of the atmosphere with clouds of poisonous sulfuric acid. Both the USSR and America have sent spacecraft to the planet. The USSR has successfully landed probes on the surface of the planet. The Magellan spacecraft was an American probe launched in 1989. It was launched from the space shuttle and created a detailed radar map of the planet. The atmosphere is so thick that it is impossible to view the surface without radar. Scientists on earth have been interested in the conditions on Venus because of what is called the greenhouse effect. The atmosphere around Venus is so thick that the sun's radiant energy gets through, hits the surface, and then reflects back. But because of the thick carbon dioxide atmosphere, the heat is trapped and can't go back into space. As a result, the temperatures on the planet are the highest of any planets in our solar system. Our scientists are concerned that a similar condition could develop in the earth's atmosphere if certain gasses continue to build up. Earth is the third planet from the sun. It is called a living planet because it is constantly changing. Three-fourths of the planet's surface is covered by water. 9

The solid land masses are actually on several plates, or sections, of the earth's crust that float on the liquid interior of the planet. These plates are constantly moving and shifting. There are volcanoes under the ocean floor that stretch along a series of faults or cracks in the crust. Molten material from the interior of the planet is released through these vents. As this happens, the plates move apart. The plates only move a little each year, but over millions of years there is a definite change. The continental plates move only one or two inches a year, but over time there have been huge changes. Two hundred million years ago all land masses were connected as the same land mass called Pangaea (Pan je a). Then over time, the continents have drifted apart. They continue to move today as every year Europe moves about two inches further from the United States. Plates can collide. The Himalayan mountains are a result of India colliding into the Asian plate. The plate India is on is going under the Asian plate, causing the Himalayan mountains to get larger every year. Sometimes when plates come together, they rub against one another. The Pacific Ocean plate is rubbing against the North American plate along the San Andreas Fault in California. There is much earthquake activity in this region as a result. The three main layers of the earth are the crust, the mantle, and the core. The crust is the outer layer and it varies in thickness from three to twenty-five miles thick. We can compare the earth to an apple. The crust is about as thin as the skin on the apple. Between the crust and the mantle is an area called the Moho. Rocks are very dense in this area. The mantle is an area of intense heat and pressure. Rocks in this area are so hot that they can flow like a liquid. This is where lava comes from. Under the mantle is the core, which is made up of two sections. The outer core is probably liquid iron, and the inner core is probably solid iron. Viewed from space, our 10

planet is like a huge blue ball with dark land masses and swirling white clouds. It is the only planet in our solar system with such an abundance of liquid water. On Venus, there is water in the atmosphere as vapor. On Mars, there is evidence of water once flowing across the surface. But on Earth, the water seems to be everywhere. It is in the atmosphere, frozen in the ice caps, and of course, it is found in our oceans, lakes, and rivers. Water and the important gasses of our atmosphere have created just the right conditions for life as we know it. Our planet is 93 million miles from the sun, which provides the heat and energy necessary for life. The light from the sun is used by the green plants of Earth in the process called photosynthesis. During photosynthesis, green plants change carbon dioxide, water, minerals from the soil, and sunlight into food for the plants and oxygen for animals. The sun's energy also evaporates water from the oceans to power the water cycle and provide fresh water. Obviously, we also need the heat energy of the sun to keep our planet's temperatures within a range suitable for life. Our planet is constantly changing because of the movement of the plates and the forces of nature. Water and wind erode the land and change the appearance of the earth's surface. An example is the Appalachian mountain range of the east coast of America. At one time in history, this mountain range was as tall, if not taller, than the Rocky mountains out west. But today there is no comparison. The Appalachian Mountains have worn down over millions of years. Another example has to do with the moon. There is no water or atmosphere on the moon and the surface has remained pretty much unchanged for millions of years. The boot prints left by astronauts back in 1969 are still as fresh and undisturbed as the day they were made. On earth, there is little evidence of past cratering because wind and water have erased them. This crater in Arizona is esti- 11

mated to be about 50,000 years old. Within time it will be weathered away. The moon is the earth's only natural satellite. Many planets have moons; in fact, they usually have more than one. The other unusual situation is that the moons of other planets are much smaller than the planets they orbit. The earth's moon is one-fourth the diameter of the earth's diameter. The moon has an effect on earth's oceans. The moon's gravity causes the tides in our oceans. The moon takes 27 days to go around the earth. It also takes that time to turn once on its axis so we always see the same side of the moon. In fact, it wasn't until the 1960s when spacecraft were sent to orbit the moon and take pictures that we could see the far side of the moon. For a long time, the origin of the moon was debated. Several theories were suggested, but from the study of moon rocks brought back by astronauts, the latest theory was established. This theory says that the moon and earth formed at the same time when something collided with the forming planet. Some of the material from this collision flew into orbit around what would become the earth. This material collected together to form the moon. Mars is the fourth planet from the sun. Mars is about half the size of Earth. Iron oxide in the Martian soil gives it a red appearance. In 1971, a probe called Mariner 9 was sent into orbit around Mars. It sent back over 7,000 pictures of the planet's surface. Some very extraordinary things were discovered. The largest volcano in our solar system, the Olympus Mons, is on Mars. The volcano is almost twice the height of Mt. Everest. The Olympus Mons is 15 miles high. Also on Mars is a canyon system that makes the Grand Canyon look like a ditch by the side of the road. The Valles Marineris stretches for nearly 3000 miles, which is like traveling from New York to San Francisco. 12

In 1975, two probes called Viking 1 and Viking 2 were launched to Mars. Once in Martian orbit, each probe released a lander. The landers were designed to be controlled from earth. Each lander used a robotic arm to scoop up soil samples. The samples were tested for water content and signs of life. Beyond the orbit of Mars is a region called the Asteroid Belt. This is a region filled with space debris. Possibly a planet was supposed to occupy this orbit, but it never completely formed, or maybe it collided with something and exploded into thousands and thousands of pieces. These asteroids range in size from fragments the size of grains of sand to pieces the size of the state of Texas. Past the Asteroid Belt are the outer planets. The next part in this series will discuss each of the outer planets. End of Part One Part Two: THE OUTER PLANETS The solar system is vast. The outer planets are found at unbelievable distances from the sun and our planet Earth. To get an idea for this vastness, we will make a scale model of the orbits of all nine planets. In this scale, one inch will equal a million miles. We'll need a large area to do this demonstration so this field will be handy. At one end of the field is the sun. Then 36 inches away is the planet Mercury, which is about 36 million miles away. Next comes Venus, which would be about 67 inches in our model. Then Earth is positioned about 93 inches away from our make-believe sun. Now the fourth planet, Mars, is positioned 141 inches away. Then comes Jupiter, which is 483 million miles from the sun. Saturn is almost twice the distance from the sun as Jupiter. Then, almost twice as far from the sun, comes Uranus. Neptune is another billion miles from the sun. Finally Pluto is found at an average distance of 3,666 million miles from the sun. Remember, the planets orbit the sun, so they cover a huge area during a years time. 13

Remember that in the first video we talked about the use of a light-year to measure distances in space. Well, to put things into perspective, if we want to include the nearest star to us other than our sun, we would have to expand our view quite a bit. Using the same scale of one inch equals a million miles, the closest star to us would be a great distance from this playing field. This field is near Chicago, and to include the nearest star we would have to travel to St. Louis. Remember that this is the closest star and there is nothing else between our solar system and this star. The solar system and universe are extremely immense. The outer planets are different from the inner planets in many ways. The inner planets have solid surfaces and dense cores of iron. The outer planets are made up of the four gas giants--jupiter, Saturn, Uranus, and Neptune, plus the tiny planet Pluto. The huge gas planets are mainly made up of hydrogen and helium. They have swirling atmospheres and thick clouds of various colors. Pluto is the oddball of the solar system for it is more closely related to the inner planets than the outer planets. Jupiter is the first of the outer planets. It is the largest planet in our solar system and weighs twice as much as all the other planets combined. Jupiter is so large that 1000 earths could fit inside. The planet's upper atmosphere is mostly hydrogen. Thousands of miles below this atmosphere the pressure is so great the hydrogen gas turns to liquid. There may be a small core of rock and iron under this surface of liquid hydrogen. The clouds of Jupiter are very colorful and unique. There is a storm on Jupiter that has been active for over three hundred years. It is called The Great Red Spot and is larger than three planets the size of earth. It was first observed in 1665. The Voyager spacecraft sent many pictures of Jupiter and discovered a ring system around this enormous planet. 14

Jupiter has sixteen moons. The four largest moons were actually discovered by the great astronomer Galileo Galilei. These moons have been carefully studied and photographed by space probes. Io is the only moon in the solar system to have active volcanoes. Lava flows out of some of the volcanoes and moves onto the surface, changing it. Ganymede is the largest moon in the solar system. It is even larger than the planet Mercury. This moon is covered by ice. The second largest moon is Callisto, which is heavily cratered and also covered by ice. Europa is covered by a thick layer of ice. It has no craters or mountains. It looks like a cracked egg shell. The next planet is Saturn and it is the second largest planet in our solar system. Like Jupiter, Saturn is a gas giant. The most spectacular thing about Saturn is its ring system. The rings are made up of dust and ice. They start about 30,000 miles from the planet and extend about 170,000 miles into space. Some of the ring systems are very complicated, such as the F ring that has braids and twists. Saturn has many moons; as of 1994 the total was eighteen. The largest moon of Saturn is Titan. It is larger than Mercury and is covered by a thick atmosphere of nitrogen. Beyond Saturn is Uranus. Uranus is twice as far from the sun as Saturn. It has a very unusual tilt. Uranus is tilted ninety degrees on its axis, which means the north and south poles are pointed towards the sun. It takes Uranus 84 years to go around the sun once. During that time, one side of Uranus is in complete darkness for 42 years and in complete sunlight for 42 years. Like the other gas giants, Uranus has a ring system. There are at least fifteen moons orbiting Uranus. 15

The last giant gas planet is Neptune. It is about the same size as Uranus and may have a rocky core surrounded by a surface of ice. The thick atmosphere is made of hydrogen and helium. Neptune also has a system of rings. Pluto is the smallest planet. It is so far from the sun that it takes 248 years to travel around the sun once. Pluto has a very strange orbit that takes it inside the orbit of Neptune at times. That means that Pluto can actually be closer to the sun than Neptune at times. Since 1979, Neptune has been the farthest planet from the sun. This will continue until 1999. Because of this unusual orbit, many scientists think Pluto may have been a moon of Neptune that fell into its own orbit around the sun. In 1978, a moon was discovered orbiting around Pluto. Pluto is so far away that little is known about it. All of our information about other planets has been supplied to us through the use of space probes. Humans have visited our moon, but no one has ever gone to a different planet. That kind of exploration can be taken care of by spacecraft that are controlled from earth. It makes good sense to send unmanned probes whenever possible to avoid danger to life. Space probes can gather all kinds of information and then send it back to huge receiving antennas on earth where the data can be analyzed and interpreted. Here is an example of the sophistication of such probes. This is a probe planned for the late 1990's. It is an unmanned mission to Mars. The space probe will not only take pictures and readings from the surface, but it will also gather soil samples that will then be sent back to earth through a complicated system of exchanges and finally a rocket trip back to earth. It is our fascination with the unknown that keeps us searching for answers to questions about our planet and our neighbors in the solar system. But even beyond the boundaries of our own place in space, we have attempted to reach out to the rest of the universe. 16

It took years for the Voyager spacecraft to reach the outer planets and nearly ten years for the two probes to leave our solar system. Carried on board each of these probes is a plaque with a map showing how to get to our planet. In addition, there is a gold-plated record containing messages in every world language and an assortment of sounds from the animals of earth. The Voyagers will continue to fly through space for many years to come and just maybe they will help guide other explorers to us. 17

AGC/United Learning 1560 Sherman Avenue, Suite 100 Evanston, Illinois 60201 (800) 323-9084, Fax (847) 328-6706 http://www.agcunitedlearning.com e-mail: info@agcunited.com 18 Space Exploration: Our Solar System Catalog #2938 ISBN No. 1-56007-450-7