1. Astronomy 101 The Solar System Tuesday, Thursday Tom Burbine tomburbine@astro.umass.edu

2. Course Course Website: –http://blogs.umass.edu/astron101-tburbine/http://blogs.umass.edu/astron101-tburbine/ Textbook: –Pathways to Astronomy (2nd Edition) by Stephen Schneider and Thomas Arny. You also will need a calculator.

3. HW #3 On Spark under Assessments: Due Date: February 2, 2010 1:00 PM

4. Metric System 1 kilometer = 1,000 meters 1 meter = 100 centimeters 1 centimeter = 10 millimeters

5. Scientific Notation 10000 = 10 4 100000000 = 10 8 10000000000 = 10 10 100000000000000000000 = 10 20 0.001 = 10 -3 0.0000001 = 10 -7

6. How do you write numbers? 31700000 = 3.17 x 10 7 2770000 = 2.77 x 10 6 0.00056 = 5.6 x 10 -4 0.0000078 = 7.8 x 10 -6

7. How do you do multiply? 10 6 x 10 8 = 10 (6+8) = 10 14 10 -5 x 10 3 = 10 (-5+3) = 10 -2 (3 x 10 4 ) x (4 x 10 5 ) = 12 x 10 (4+5) = 12 x 10 9 = 1.2 x 10 10

8. How do you divide? 10 8 /10 6 = 10 (8-6) = 10 2 10 -6 /10 -4 = 10 (-6-(-4)) = 10 -2 (3 x 10 8 )/(4 x 10 3 ) = ¾ x 10 (8-3) = 0.75 x 10 5 = 7.5 x 10 4

9. How many stars in the Universe Say there are 100 billion galaxies Each galaxy has 100 billion stars So how many stars in the universe

10. Answer Number of stars in universe = (100 x 10 9 ) x (100 x 10 9 ) = 10000 x 10 18 = 1 x 10 22 = 10,000,000,000,000,000,000,000 This is about the same number of grains of sand in every beach in the world

11. Questions: How many of these 10 22 stars have planets? How many of these planets have life?

12. My - Mercury Very - Venus Eager - Earth Mother - Mars Just - Jupiter Served - Saturn Us -Uranus Nine -Neptune Pizzas - Pluto

13. Does anyone play basketball?

14. Assume That the sun is the same size as a basketball Basketball diameter = 24.4 cm Sun Diameter = 1.4 x 10 9 m = 1.4 x 10 11 cm Scale Factor = 1.74 x 10 -10 Multiply scale factor by actual diameters of planets to get their approximate size

15. Mercury Diameter = 4.88 x 10 6 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 8.5 x 10 -4 m = 0.85 mm

17. Venus Diameter = 1.21 x 10 7 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 2.1 x 10 -3 m = 2.1 mm

19. Earth Diameter = 1.28 x 10 7 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 2.2 x 10 -3 m = 2.2 mm

21. Mars Diameter = 6.80 x 10 6 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 1.2 x 10 -3 m = 1.2 mm

23. Jupiter Diameter = 1.43 x 10 8 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 2.5 x 10 -2 m = 25 mm = 2.5 cm

25. Saturn Diameter = 1.21 x 10 8 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 2.1 x 10 -2 m = 21 mm = 2.1 cm

27. Uranus Diameter = 5.18 x 10 7 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 9.0 x 10 -3 m = 9 mm

29. Neptune Diameter = 4.95 x 10 7 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 8.5 x 10 -3 m = 8.5 mm

31. Pluto Diameter = 2.30 x 10 6 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 4.0 x 10 -4 m = 0.4 mm

34. What if we want to use the same scale factor to make a model of the solar system? What’s the problem?

35. How far away is Pluto? Pluto is 5.9 x 10 12 m from Sun on average Multiply by scale factor (1.74 x 10 -10 ) Relative Distance from Sun = 1027 m = 1.027 km

36. Seasons http://www.learner.org/resources/series28.html

38. Phases of the Moon- 29.53 day cycle

39. http://en.wikipedia.org/wiki/File:Lunar-Phase-Diagram.png

40. Eclipses Moon is tilted at an angle of 5 degrees to Earth’s orbit

42. http://astronomyonline.org/SolarSystem/LunarEcl ipse.asphttp://astronomyonline.org/SolarSystem/LunarEcl ipse.asp

43. Color of lunar eclipse The Moon does not completely disappear because of the refraction of sunlight by the Earth’s atmosphere If the Earth had no atmosphere, the Moon would be completely dark during an eclipse. The red color arises because sunlight reaching the Moon must pass through the Earth’s atmosphere, where it is scattered. Shorter wavelengths are more likely to be scattered by the small particles. By the time the light has passed through the atmosphere, the longer wavelengths dominate. This resulting light reflected from the Moon we perceive as red.

44. Solar eclipse

46. http://en.wikipedia.org/wiki/Image:Solar_eclips_1999_4_NR.jpg Solar eclipses occur approximately every 18 months However, they recur (on average) at any given place only once every 370 years Moon's umbra moves eastward at over 1,700 km/hr Every year, there are at least two lunar eclipses. Can be viewed anywhere on the night side of the Earth http://home.cogeco.ca/~astrosarnia/Photos/Lunar%20eclipse%20binocular.jpg

47. Solar eclipse of July 22, 2009 Lasted a maximum of 6 minutes and 39 seconds off the coast of Southeast Asia http://en.wikipedia.org/wiki/File:Solar_eclipse_22_July_2009_taken_by_Lutfar_Rahman_Nirjhar_from_Bangladesh.jpg http://upload.wikimedia.org/wikipedia/commons/f/f2/Solar_eclipse_animate_%282009-Jul-22%29.gif

48. Any Questions?