The Planets of the Solar System

1. The Planets of the Solar System Chapter 3 Lesson 12

2. The Planets of the Solar System • Space is full of natural objects. Some are close to Earth and some are far away. • The objects closest to us are part of our solar system. • The main parts of our solar system are the sun and the eight planets that travel around it.

3. The Planets of the Solar System • A planet is a large round object that travels in a set path around a star. • The sun is a star. • Each of our solar system’s planets is both similar and different from the others.

4. The Sun, Earth’s Closest Star • It might sound surprising to call the sun a star. • A star is a huge ball of hot gases that gives off its own light. • There is a good reason the sun looks so different compared to the other stars we see in the night sky. • The sun is much closer to us than any of the other stars.

5. The Sun, Earth’s Closest Star • Although the sun is still far away, it is close enough for us to see by its light and feel its heat. • Planets do not give off their own light. Then how do we see them at night???- Because they reflect sunlight to your eyes. • Earth is visible from space because sunlight bounced off Earth’s land, oceans, and atmosphere.

6. Ways that the Planets Are Similar • The motions of the planets are all somewhat similar. Each planet revolves around the sun. • To revolve means to move in a fixed path around another object. (walking around your desk)

7. Ways that the Planets Are Similar • Each planet rotates on its axis. • To rotate means to spin on an axis. • An axis is an imaginary line that runs through a planet from its north pole to its south pole. (ice skater spinning on a spot on the ice)

8. Ways that Planets Are Different • None of the planets are exactly like the others. • The planets move around the sun at different distances from it. • A planet’s orbit is its path around the sun. Each planet takes a different amount of time to make one trip around the sun. • The amount of time for a planet to go around the sun once is the planet’s year.

9. Ways that Planets Are Different • Each planet takes a different amount of time to spin once on its axis, as well. • One complete spin of a planet on its axis is the length of its day.

10. Solar System Data

11. Solar System Data • What information can you gather from the chart? • The farther a planet is from the sun, the longer its year is. That is because the planets path around the sun is longer the farther it is from the sun.

12. The Inner Planets • Mercury, Venus, Earth, and Mars are known as the inner planets. • They are the four planets closest to the sun and they are small and rocky.

13. Mercury • Closest planet to the sun. • Daytime temps reach 662oF. • Nighttime temps reach -274oF. • No liquid water. • Surface is pockmarked with craters.

14. Venus • Second closest planet to the sun. • Average temp is 896oF. • No liquid water. • Surface covered with canyons, volcanoes, valleys, mountains, craters, and plains. • Atmosphere is almost as thick as Earth’s, but it is made up of mostly carbon dioxide.

15. Earth • Third planet from the sun. • About ¾ of Earth’s surface is covered with water. • Atmosphere is 78% nitrogen, 21% oxygen, and 1% other gases. • Average temp is 68oF.

16. Mars • Fourth planet from the sun. • Temps range from 68oF to -220oF. • Some evidence has been found that water once flowed over the surface of Mars, but the only water now is ice at the poles. • Surface is spotted with craters and covered with mountains, valleys, extinct volcanoes, and plains. • Known as the “red planet” • Red color comes from rust-like substance on its surface. • Atmosphere is mostly carbon dioxide gas.

17. The Outer Planets • The outer planets include Jupiter, Saturn, Uranus, and Neptune. • They are the four planets farthest from the sun. • They are large and made up mostly of gas.

18. Jupiter • Fifth planet from the sun. • Largest planet in our solar system. • Atmosphere made up mostly of hydrogen and helium gas and parts are very colorful. • It has a huge red area called the Great Red Spot that is a storm that has been raging for hundreds of years. • Surrounded by a thin set of rings that are hard to see.

19. Saturn • Sixth planet from the sun. • Second largest planet in the solar system. • Atmosphere is thick. • Has the largest system of rings and they are made up of bits of ice and rock. These rings can be seen through a telescope.

20. Uranus • Seventh planet from the sun. • Third largest planet in the solar system. • Temperature of the clouds is -357oF. • It is green because of methane gas. • Uranus has rings but they are not as prominent as Saturn’s. • It’s axis is also tilted at much more of an angle than any of the other planets.

21. Neptune • Eighth planet from the sun. • Temperature of the clouds is around the same temperature as Uranus and so is the atmosphere. • Winds in the atmosphere have been measured at 684 miles an hour. • Neptune is surrounded by fewer rings than Uranus and Saturn.

22. Movements of the Planets in the Night Sky • If you watch the planets in the night sky, you may notice that their positions change in relation to the stars. • The stars seem to stay in the same patterns, while the planets move to different places. • Stars move in space, but they are so far away from Earth that we cannot see their movement. • We see the movement of the planets because they are much closer to Earth. We see them change positions against the background of stars.

23. 1. Which planet has the largest system of rings? • A. Uranus • B. Saturn • C. Neptune • D. Mercury

24. 1. Which planet has the largest system of rings? • B. Saturn

25. 2. Which planet takes the longest time to make one orbit around the sun? • A. Mars • B. Mercury • C. Neptune • D. Jupiter

26. 2. Which planet takes the longest time to make one orbit around the sun? • C. Neptune

27. 3. Which is the only planet in the solar system that is known to support life? • A. Mars • B. Venus • C. Earth • D. Saturn

28. 3. Which is the only planet in the solar system that is known to support life? • C. Earth

29. 4. Which planets are made up of mostly of gases? • A. Mercury, Venus, Earth, and Mars • B. Jupiter, Saturn, Uranus, and Neptune • C. Earth, Jupiter, Saturn, and Earth • D. Venus, Uranus, Neptune, and Jupiter

30. 4. Which planets are made up of mostly of gases? • B. Jupiter, Saturn, Uranus, and Neptune