theonion/content/node/32096

1. http://www.theonion.com/content/node/32096

2. Lecture 21

3. Outline For Rest of Semester • Oct. 29th Chapter 9 (Earth) • Nov 3rd and 5th Chapter 9 and Chapter 10 (Earth and Moon) • Nov. 10th and 12th Mars, Venus, and Mercury • Nov. 17th and 19th Jupiter and Saturn • Nov 24th Uranus and Neptune • Nov 26th Thanksgiving • Dec. 1st - Exam 3 • Dec. 3rd – Pluto, and the Kuiper Belt • Dec. 8th and 10th – Chapter 7 and 8 (Comparative Planetology I and II) • Tuesday December 15th (7:30 am – 10:15 am) Final Exam • No Reading days are scheduled this semester • Exam Periodbegins at 7:30 a.m. on Monday, December 14 and ends on December 21

4. Outline • Jupiter and Saturn • Orbit • Surface • Atmosphere • Rings • Moons

5. Questions • On posting “(with answers)” notes • NASA finding water on the moon • Why so many questions? •  I have not had a chance to post Quiz solutions in ppt recently • #18 “made no sense”

6. #18 Mars’ Atmosphere • Why does Earth have oxygen in its atmosphere while Mars does not?

7. Venus Greenhouse • The so-called greenhouse effect, which produces very high temperatures on the surface of Venus, is … The absorption of CO2 gas by the planet’s atmosphere of infrared radiation emitted by its surface.

8. Mercury Elongation

9. Outline • Jupiter and Saturn • Orbit • Surface • Atmosphere • Rings • Moons

10. It is difficult to see! http://homepage.ntlworld.com/mjpowell/Astro/Naked-Eye-Planets/Naked-Eye-Planets.htm

11. Why is the ecliptic at an angle with respect to the horizon?

14. Typo? • More than 1200 Earth’s would fit inside Jupiter • Jupiter is 11 times larger in diameter than Earth

15. Typo? No! • More than 1200 Earth’s would fit inside Jupiter • Jupiter is 11 times larger in diameter than Earth V ~ R3 ~ D3 = (pi/6)D3 VEarth ~ D3Earth VJupiter ~ (11*DEarth)3 ~ (11)3 D3Earth~ 1300 D3Earth

17. Inferior planets superior planets

21. A planet’s synodic period is measured with respect to the Earth and the Sun (for example, from one opposition to the next)

22. Periods • Rotational • Orbital • Sidereal • Synodic Measured with respect to something that is not rotating or orbiting

23. Orbit • http://learning.nd.edu/orbital/orbitals.swf

24. Extra-credit in-class Quiz Use cell phone if • If you have free text plan and • Don’t mind receiving ads otherwise Use notecard and hand in at end of class

25. Register for quiz 2 Text to 41411: astr111 2 rweigel You will receive either one or two texts in response Replace with your GMU email name

26. Question • Which is longer, Jupiter’s synodic or orbital period? • Which is longer, Jupiter’s synodic or Saturn’s synodic period? • Guess Jupiter’s and Saturn’s synodic period.

27. Which is longer, Jupiter’s synodic or orbital period? • Which is longer, Jupiter’s synodic or Saturn’s synodic period? • Guess Jupiter’s and Saturn’s synodic period. 2 1 a Synodic, Jupiter’s, longer than Earth’s 2 1 b Synodic, Saturn’s, longer than Earth’s 2 1 c Synodic, Saturn’s, shorter than Earth’s 2 1 d Synodic,Jupiter’s, shorter than Earth’s 2 1 e Orbital, Jupiter’s, longer than Earth’s 2 1 f Orbital, Jupiter’s, longer than Earth’s 2 1 g Orbital, Saturn’s, longer than Earth’s 2 1 h Orbital, Saturn’s, longer than Earth’s

28. Time to repeat from Earth’s perspective Question • Which is longer, Jupiter’s synodic or orbital period? orbital • Which is longer, Jupiter’s synodic or Saturn’s synodic period? Jupiter’s • Guess Jupiter’s and Saturn’s synodic period. A little longer than Earth’s orbital period.

29. Kepler’s Third Law P2 = a3 P = planet’s sidereal period, in years a = planet’s semimajor axis, in AU

30. Long orbital periods of Jupiter and Saturn cause favorable viewing times to shift

31. What is wrong with either of these tables?

32. What is wrong with either of these tables? Correct

33. The best time to observe Saturn from Earth is when it is • at opposition and it is midnight at your location on Earth. • at opposition and it is sunset or sunrise at your location on Earth. • at conjunction and it is midnight at your location on Earth. • at conjunction and it is sunset or sunrise at your location on Earth. • at opposition and it is just before sunrise at your location on Earth. 2 2 2 2 2 2 2 2 2 2

34. The best time to observe Saturn from Earth is when it is • at opposition and it is midnight at your location on Earth. • at opposition and it is sunset or sunrise at your location on Earth. • at conjunction and it is midnight at your location on Earth. • at conjunction and it is sunset or sunrise at your location on Earth. • at opposition and it is just before sunrise at your location on Earth.

36. Outline • Jupiter and Saturn • Orbit • Surface • Atmosphere • Rings • Moons

37. What happens to ornaments when hoop is spun? hoop

41. hoop 2 3 A 2 2 B 2 2 C 2 2 D

42. How to get Oblate hoop

43. The farther away from the axis, the more “thrown out” it gets.

45. Extra-credit in-class Quiz Use cell phone if • If you have free text plan and • Don’t mind receiving ads otherwise Use notecard and hand in at end of class All questions (correct or incorrect) worth 20 points (about two quiz questions).

46. Register for quiz 3 Text to 41411: astr111 3 rweigel You will receive either one or two texts in response Replace with your GMU email name NOT G NUMBER!

47. Both have arms attached to ears and shoulders. When they spin, which pair of arms swings out the most? Least? Y Y W W Z Z X X 3 1 • X Most, Y Least • Y Least, X Most • W Most, Y Least • X,Y,Z Most, W Least • W Most, X, Y, Z Least 3 1 3 1 3 1 3 1

48. Both have arms attached to ears and shoulders. When they spin, which pair of arms swings out the most? Least? Y Y W W Z Z X X 3 1 • X Most, Y Least • Y Least, X Most • W Most, Y Least • X,Y,Z Most, W Least • W Most, X, Y, Z Least 3 1 3 1 3 1 3 1

49. The farther away from the axis, the more “thrown out” it gets.

50. Both have arms attached to ears and shoulders. When they spin, which pair of arms swings out the most? Least? All red arms are same distance from spin axis. Black arms are closer. Red arms swing out most. Black arms wing out least.