1. SOLAR SYSTEMS
CHAPTER 21

2. definition Objects that revolve around a star Major members
Planets
Moons
Minor members
Dwarf planets
Asteroids
Comets
meteoroids

3. What is a planet? (as of Aug. 2006)
The IAU said that the definition for a planet is now officially known as "a celestial body that
(a) is in orbit around a star
(b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a (nearly round) shape and
(c) has cleared the neighborhood around its orbit." (not in a swarm of rocks)

4. Our solar system scoreboard
Planets= 8
Moons= 167
Dwarf planets= 5
Asteroids= 536,000+
Comets= 3,062

5. Exosolarsystems Other solar systems 565 new solar systems confirmed!
Over 687 planets (exoplanets)
First discovered in 1995
Estimated over 50 BILLION

6. Earth like planets (habitable zone)
Maybe 2?
Gliese D
6x more massive than earth “superearth”
In Libra
20 lya
HD b
In Vela
26 lya

7. METHODS to find a new planet

8. Radial Velocity
Planets are detected by studying light shifts due to star wobbles
Uses Doppler Effect
Red light moves towards
Blue light moves away

9. Astrometry
Measures star wobbles from geometry

10. Transit method Planet blocks star (eclipse) Light from star is lessen
Kepler mission

11. Optical detection
Block star’s light out using a chronograph

12. List of exoplanets

13. Exoplanet missions
Kepler- launched 2009
Has found 7 planets so far

14. Other research LBT (large binocular telescope)
Keck telescopes (Hawaii)
Spitzer Space Telescope
Infrared telescope

15. Our Solar System

16. Our solar system

18. The planets drawn to scale

19. INNER PLANETS

20. INNER PLANETS Terrestrial Rocky No rings
Smaller compared to Outer planets

21. MERCURY No atmosphere Temperatures fluctuate wildly
MESSANGER is currently orbiting Mercury- has completed 282 orbits (so far!)

22. Sept. 29, 2009 MESSANGER

23. Messenger 9/21/11
Mapping surface of Mercury

24. VENUS THICK atmosphere Rotation is retrograde Hot! Crushing pressure
Sun rise in west; set in east

25. Pancake volcanoes

27. MARS Thin atm. Windy Surface similar to Earth Volcanoes
Old river valleys- where’s the water?
Best chance to find fossil (life?) in SS

29. Opportunity and Spirit

30. Mars Moons
Phobos
Deimos

32. Jovian Planets Outer planets Large Many moons all have rings
Made of gas

33. JUPITER
Often captures comets/asteroids
Shoemaker/Levy comet (1994)

34. Jupiter’s Ring system Feb. 2007

35. Jupiter’s New Moons Jupiter now has 63 known moons
23 moons were discovered in by Earth-based telescopes

36. Saturn’s Rings Made of Water ice and dust
Sheppard moons keep rings in place

38. Uranian Weirdness

39. A few of Uranus’s moons
MIRANDA
PUCK
ARIEL
OBERON

40. Neptune
Very active weather

41. Triton- Liquid nitrogen volcanoes Cantaloupe terrain
Underground oceans?
Alien life?

43. Planet ?
2003 UB313
Renamed Eris (Xena)

44. What is a planet? (as of Aug. 2006)
The IAU said that the definition for a planet is now officially known as "a celestial body that
(a) is in orbit around a star
(b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a (nearly round) shape and
(c) has cleared the neighborhood around its orbit." (not in a swarm of rocks)

45. Pluto
Dwarf planet

47. Lowell Observatory where Pluto was discovered 1939

49. Plutoids
Dwarf planets beyond Neptune
Established in 2008

50. Planets, dwarf planets, plutoids

51. How many moons does Pluto have?

52. We’re on the way… New Horizons spacecraft was launched in Jan. 2006
Will arrive at Pluto July 2015