1. O UTER P LANETS

2. L ETS REVIEW Name the four inner planets? What was there surface consisting of? What name were the four inner planets known as? Hint starts with a T

3. Most of what astronomers know about outer planets have come from space probes Compared to Earth some planets are huge Jupiter is 11 times larger If Earth were a Chihuahua Jupiter would be a Great Dane

4. four outer planets Jupiter, Saturn, Uranus, & Neptune Do not have solid surface Called Gas Giants Stronger gravitational force Partly solid core

5. J UPITER

6. Most massive planet Thick atmosphere of hydrogen and helium Colorful bands of thick clouds Great Red Spot: ongoing storm

7. J UPITER ’ S M OONS 4 moons: Io, Europa, Ganymede, Callisto Are 4 largest Later have discovered many more Io Covered with volcanoes Looks like giant pizza Europa Icy crust Ganymede Largest, icy and partly covered with craters Callisto Icy surface and every part covered with craters

8. F OLDABLE 5 th planet from the sun Largest planet Atmosphere is made mostly of hydrogen, helium, methane, and ammonia Great Red Spot is a ongoing storm Has a ring system Four large and 24 small moons Day=9hours56min Year=12 years

9. S ATURN

10. 2 nd largest Slightly smaller than Jupiter but with rings has greater diameter Thick atmosphere Contains clouds and storms Only planet less dense then water

11. S ATURN ’ S RINGS AND MOONS Rings made of chunks of ice and rock HUNDREDS of rings Each travel in their own orbit around Saturn Broad and think like a cd Recently rings have been discovered around other 3 gas giants but not as spectacular as Saturn's Many moons Largest called Titan: little light gets through

12. F OLDABLE 6 th planet from sun 2 nd largest planet Thick atmosphere At least thirty moons Largest moon: Titan (larger than Mercury) Less dense than water Has a ring system Day= 10 hours 39 min Year=29 years

13. U RANUS

14. 4 times the diameter of Earth but much smaller than Jupiter and Saturn Twice as far from sun as Saturn so much colder Looks bluish because of traces of methane in atmosphere First new planet discovered since 1781 Thought it might be a comet but when studied had an orbit just beyond Saturn Started major space exploration at the time

15. In 1986 Voyager 2 sent back our only close up views Only a few clouds Rotates in 17 hours Axis tilted at 90 degrees Rotates top to bottom instead of side to side Astronomer think a object hit it and turned it on its side 27 moons 5 largest icy, cratered surfaces, lava flows (comes from inside)

16. F OLDABLE 7 th planet from sun Third largest Has ring system Axis at 90 degrees (rotates top to bottom) 27 moons Atmosphere of hydrogen, helium, methane, and ammonia Methane caused bluish appearance Day=17 hours 14 min Year=84 years

17. N EPTUNE

18. 30 times farther from Sun than Earth Contains visible clouds 1989 Voyager flew past and discovered Great Dark Spot(about size of Earth) Probably a giant storm Didn’t last long, 5 years later it was gone Other smaller spots seem to come and go

19. 13 moons Largest Triton Near south pole covered with cap of ice, dark material erupts from underneath Covered with ridges and crators

20. F OLDABLE 8 th planet from Sun Great Dark Spot: Storm as large as Earth Has high altitude winds Atmosphere made of hydrogen, helium, methane, and ammonia Methane causes blue color Has 13 moons (Triton=largest) Has a ring system Day=16 hours 6 min Year=165 years

21. P LUTO & CHARON

22. Solid surfaces Less than 2/3 size of Earth’s moon Moon Charon is more than 1/2 size of Pluto considered double planet Revolve once every 248 years Astronomers don’t know much about them Pluto discovered in 1930, Charon in 1978

23. Is it really a planet? Many astronomers say it is too small Say it is just the largest of thousands of objects revolving around the sun beyond Neptune If astronomers had found these other objects before Pluto might not have called it a planet

24. F OLDABLE 9 th planet from Sun Atmosphere is nitrogen, carbon monoxide, and methane, Moon, Charon, half the size of Pluto Oval orbit sometimes puts it closer to the sun than Neptune 248 days to revole Solid Surface