Unit 2 Lesson 1 What Objects Are Part of the Solar System? Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 1 What Objects Are Part of the Solar System? Florida Benchmarks SC.5.E.5.2 Recognize the major common characteristics of all planets and compare/contrast the properties of inner and outer planets. SC.5.E.5.3 Distinguish among the following objects of the Solar System—Sun, planets, moon, asteroids, comets—and identify Earth’s position in it. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 1 What Objects Are Part of the Solar System? Planets are large, round bodies that revolve around a star. There are eight planets in our solar system. All planets rotate, or spin, around an axis. An axis is an imaginary line that goes through the center of the planet. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 1 What Objects Are Part of the Solar System? The Inner Planets The four inner planets are Mercury, Venus, Earth, and Mars. The inner planets are very dense and rocky. They also have thin atmospheres and small diameters. The inner planets have large solid cores and few moons. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 1 What Objects Are Part of the Solar System? The Outer Planets The planets farthest from the sun are Jupiter, Saturn, Uranus, and Neptune. The outer planets are known as gas giants. They are huge and made up mostly of gases. All of the outer planets have many moons and ring systems. Copyright © Houghton Mifflin Harcourt Publishing Company

Compare Inner and Outer Planets Unit 2 Lesson 1 What Objects Are Part of the Solar System? Compare Inner and Outer Planets Size, surface features, distance from the sun, temperatures, number of moons, and diameter make the inner and outer planets different. The period of revolution of a planet is the time it takes for a planet to revolve around the sun. The period of rotation of a planet is the time it takes to rotate on its axis. Copyright © Houghton Mifflin Harcourt Publishing Company

Mercury Mercury is the smallest planet in our solar system. Unit 2 Lesson 1 What Objects Are Part of the Solar System? Mercury Mercury is the smallest planet in our solar system. The surface of Mercury is full of craters. Mercury is the closest planet to the sun. Copyright © Houghton Mifflin Harcourt Publishing Company

Venus Temperatures on Venus are high enough to melt lead. Unit 2 Lesson 1 What Objects Are Part of the Solar System? Venus Temperatures on Venus are high enough to melt lead. Thick clouds on Venus are made up mostly of carbon dioxide. There are more than 1,000 volcanoes on Venus’s surface. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 1 What Objects Are Part of the Solar System? Earth Earth has an atmosphere made of mostly nitrogen, oxygen, and carbon dioxide. Earth is the only planet known to have abundant liquid water. Water helps keep Earth at temperatures that allow life. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 1 What Objects Are Part of the Solar System? Mars Mars is known as the “Red Planet” because of its red, rocky surface. Giant dust storms cover the entire planet. There are also huge volcanoes on Mars. Copyright © Houghton Mifflin Harcourt Publishing Company

Jupiter Jupiter is the largest planet in the solar system. Unit 2 Lesson 1 What Objects Are Part of the Solar System? Jupiter Jupiter is the largest planet in the solar system. Massive, spinning storms, such as the Great Red Spot, are visible on Jupiter. Jupiter has rings, but they are faint. Copyright © Houghton Mifflin Harcourt Publishing Company

Saturn Saturn is the second-largest planet in the solar system. Unit 2 Lesson 1 What Objects Are Part of the Solar System? Saturn Saturn is the second-largest planet in the solar system. Saturn has thousands of rings around it. The rings are made of ice and chunks of rock. Saturn has many moons and large storms, like Jupiter. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 1 What Objects Are Part of the Solar System? Uranus The axis of Uranus is tilted so far that it appears to rotate on its side. Heated gases deep inside Uranus bubble and burst onto the surface, causing bright clouds to form. Uranus has at least 13 faint rings. Copyright © Houghton Mifflin Harcourt Publishing Company

Neptune Winds on Neptune can reach 2,000 km/hr. Unit 2 Lesson 1 What Objects Are Part of the Solar System? Neptune Winds on Neptune can reach 2,000 km/hr. The Great Dark Spot on Neptune is a storm that travels around the planet. Neptune has nine rings around it. Copyright © Houghton Mifflin Harcourt Publishing Company