CONTENTS A SPECIAL PLACE 4 EARTH’S AMAZING FEATURES 6 INSIDE EARTH 8 A ROCKY PLACE 10 THE ROCK CYCLE 12 A BLANKET OF AIR 14 WATER EVERYWHERE 16 A PLANET FIT FOR LIFE 18 ALWAYS IN MOTION 20 THE CHANGING SEASONS 22 AN AMAZING MOON 24 EARTH’S ANCIENT PAST 26 THE FUTURE OF OUR PLANET 28 GLOSSARY 30 FOR MORE INFORMATION 31 INDEX 32
4 A SPECIAL PLACE Earth is the third planet from the sun and one of eight planets in our solar system Earth orbits or travels around the sun at an average distance of about 93 million miles 150 kilometers Earth appears bright blue and white when viewed from outer space Earth is a special planet It is the only planet in the uni verse known to support life Life is possible on Earth thanks to the oxygen in its air and water on its surface A satellite flying 435 miles 700 km over Earth captured this beau tiful image of our unique planet
5 Earthʼs average temperature can change How might rising average temperatures affect humans THINK ABOUT IT Earth’s atmosphere also is the perfect temperature for life averaging about 59 F 15 C It is not too hot like Venus or too cold like Neptune But Earth is always changing due to its many cycles and systems Understand ing how these cycles and systems work is important because human activities conti nue to affect the plan et’s surface oceans and atmosphere A photograph taken at night shows the lights of the populated areas of Taiwan and mainland China
