The Solar System

1. The Solar System • Includes the sun and the objects its gravity holds around it • Kuiper Belt • New Horizons 23.1

2. The Solar System • Geocentric theory • Ancient model of universe • Earth at center • Stars • Sun and moon 23.2

3. The Solar System • Geocentric theory • Planets • Circular orbits • Problems: • Differences in planet brightness • Retrograde motion 23.2

4. The Solar System • Geocentric theory • Ptolemy • Deferents • Epicycles • Upheld by Roman Catholic Church 23.2

5. The Solar System • Heliocentric theory • Nicolaus Copernicus • The Revolutions • Sun at center of universe • Moon orbits Earth 23.2

6. The Solar System • Heliocentric theory • Challenged by many • Copernican Revolution 23.2

7. The Solar System • Tycho • Most accurate astronomer of his time • Galileo • New telescope • Critic of geocentric theory 23.3

8. The Solar System • Kepler • Brilliant mathematician • Planets’ orbits are elliptical • Foci 23.3

9. The Solar System • Three laws of planetary motion • Planets move in ellipses with the sun at one focus 23.3

10. The Solar System • Three laws of planetary motion • A planet moves faster when closer to the sun and slower when farther away 23.3

11. The Solar System • Three laws of planetary motion • Time planets take to orbit the sun and their average distances from the sun always have the same mathematical relationship 23.3

12. The Solar System • Perihelion • Aphelion 23.3

13. The Solar System • Newton • Mathematically described gravitational force 23.3

14. The Planets • What is a planet? • IAU definition • 8 planets • Dwarf planets • Small solar system bodies 23.4

15. The Planets • What is a planet? • Classification by properties • Terrestrial • Jovian • Gas giants 23.4

16. The Planets • What is a planet? • Classification by position • Inferior • Transits • Superior • Retrograde motion 23.4

17. The Planets • Mercury • Closest to sun • Smallest • Short year, long day • No known moons 23.5

18. The Planets • Venus • Brightest planet in our sky • Appears to rotate backwards • Atmosphere 23.5

19. The Planets • Earth • Third planet from sun 23.5

20. The Planets • Mars • Reddish color • No geomagnetic field • Phobos and Deimos • Olympus Mons • Erosional features 23.5

21. The Planets • Jupiter • Fifth and largest planet • Rocky core with layer of metallic hydrogen • Great Red Spot 23.6

22. The Planets • Jupiter • Many moons • Galilean moons discovered in 1610 23.6

23. The Planets • Saturn • Equatorial bulge • Many moons • Ring system • Titan 23.6

24. The Planets • Uranus • Discovered by Herschel in 1781 • Axial tilt • Unusual structure • Faint rings 23.6

25. The Planets • Neptune • Most distant planet • More massive than Uranus, but has a smaller diameter • Rings 23.6

26. Nonplanetary • Dwarf planets • Pluto • Discovered by Tombaugh at Lowell Observatory • “Double planet” 23.7

27. Nonplanetary • Dwarf planets • Ceres • Haumea, Makemake, and Eris • Members of the Kuiper Belt 23.7

28. Nonplanetary • Small Solar System Bodies • Planetary moons • Asteroids • Comets • Meteors 23.8

29. Nonplanetary • Asteroids • Much smaller than planets • Asteroid belt • Trojans & Greeks • Near-earth asteroids 23.8

30. Nonplanetary • Comets • Composition • Head • Nucleus • Coma • Tail 23.8

31. Nonplanetary • Comets • Edmund Halley • Halley’s Comet • Periodic comets • Oort cloud 23.8

32. Nonplanetary • Meteoroids • Not visible in space even with telescope • Meteors • Meteoroid that enters atmosphere • “Shooting star” 23.8

33. Nonplanetary • Meteor showers • Meteorites • Reach earth’s surface • Form craters 23.8