1. Planets of the Solar system Section 4 Key Ideas Identify the basic characteristics that make the outer planets different from terrestrial planets. Compare the characteristics of the outer planets. Explain why Pluto is now considered a dwarf planet.

2. Planets of the Solar system Section 4 The Outer Planets Jupiter, Saturn, Uranus, & Neptune –separated from the inner planets by a ring of debris called the asteroid belt. Gas giant - planet that has a deep massive atmosphere In 2006, Pluto was reclassified as a dwarf planet.

3. Planets of the Solar system Section 4 Gas Giants Gas giants are larger & more massive, but much less dense. –did not lose their original gases during formation –has a thick atmosphere made of hydrogen & helium Each planet probably has a core made of rock & metals. All four have ring systems made of dust & icy debris.

4. Planets of the Solar system Section 4 Jupiter Fifth planet from the sun –largest planet in the solar system, more than 300 times that of Earth –orbital period is almost 12 years –rotates on its axis faster than any other planet (every 9 hours & 50 min) –has at least 63 moons, 4 of which are the size of small planets –has several thin rings that are made up of millions of particles

5. Planets of the Solar system Section 4 Jupiter’s Atmosphere & Interior Hydrogen & helium make up 92% of Jupiter, much like the sun. The orange, gray, blue, & white bands on the surface suggest organic molecules mixed with ammonia, methane, & water vapor. Jupiter’s interior is a sea of liquid, metallic hydrogen –as high as 30,000 ºC

6. Planets of the Solar system Section 4 Weather and Storms on Jupiter The Great Red Spot is a hurricane-like storm that has been raging for several thousand years. The Galileo spacecraft measured wind speeds up to 540 km/h. It has lightning & thunderstorms that are much larger than those on Earth.

7. Planets of the Solar system Section 4 Saturn Sixth planet from the sun –orbital period of 29.5 years –rotates on its axis every 10 hours & 30 min –made of hydrogen & helium –has a rocky, iron core –least dense planet in the solar system Saturn is very cold –average temperature of –176 °C Saturn has 60 moons –largest moon, Titan, is half the size of Earth.

8. Planets of the Solar system Section 4 Saturn’s Bands and Rings Saturn is known for its rings, which are 2 times the planet’s diameter. –most complex & extensive system of rings –made of billions of dust and ice particles Saturn has bands of colored clouds that run parallel to its equator. It’s rapid rotation & low density, causes Saturn to bulge at its equator & to flatten at its poles.

9. Planets of the Solar system Section 4 Uranus Seventh planet from the sun & third-largest planet in the solar system. –orbital period is almost 84 years –has at least 27 moons & at least 12 thin rings Uranus’s Rotation Uranus’s axis is almost parallel to the plane of its orbit ( turned on it’s side!) – rotates once about every 17 hours

10. Planets of the Solar system Section 4 Uranus’s Atmosphere Uranus has an atmosphere that contains mainly hydrogen & helium. –the blue-green color indicates that the atmosphere also contains significant amounts of methane –average temperature of Uranus is –214 °C

11. Planets of the Solar system Section 4 Neptune Eighth planet from the sun & is similar to Uranus in size & mass. –orbital period is nearly 164 years –rotates about every 16 hours –has at least 13 moons & six rings

12. Planets of the Solar system Section 4 Neptune’s Atmosphere Neptune’s atmosphere is made up mostly of hydrogen, helium, & methane. –has the solar system’s strongest winds, which exceed 1,000 km/h –average temperature is about –225 °C The Great Dark Spot was a giant storm the size of Earth that appeared & disappeared on Neptune’s surface.

13. Planets of the Solar system Section 4 Pluto Pluto is now defined as a dwarf planet –orbits the sun in an unusually elongated & tilted ellipse –made up of frozen methane, rock, & ice –average temperature of –235 °C –has extensive methane icecaps & a very thin nitrogen atmosphere –has three moons