Sky Motions / Time - Objectives

1. Sky Motions / Time - Objectives • Geocentric - WRONG • Heliocentric • Seasons • Moon Phases • Eclipses

2. Model • Can be something we can touch, can be a computer simulation, can be a picture. • A tool to help us understand reality. • Never perfect, always has flaws.

3. Celestial Sphere • The apparent “crystal sphere” that we would have around the Earth if the stars, planets, the Sun, and Moon were actually all the same distance from Earth. • Not real, just a model that helps us understand reality.

6. Geocentric Model • Geo = Earth • Centric = centered

7. Geocentric=WRONG

8. Day • Sun appears to rise and set • Reality: Earth spins on axis in space

10. Local noon • When the Sun transits (appears the highest in the sky) on any given day • Not usually overhead • Not usually 12:00pm

12. Time Zones

14. Galileo Galilei

17. Galileo’s Astronomy Contributions • Moon - craters • Jupiter’s moons (Galilean moons) • Venus’s phases • Saturn’s rings • Sunspots (blindness)

19. Galileo’s Astronomy Contributions • Moon - craters • Jupiter’s moons (Galilean moons) • Venus’s phases • Saturn’s rings • Sunspots (blindness)

21. Io Europa Ganymede Callisto

22. Galileo’s Astronomy Contributions • Moon - craters • Jupiter’s moons (Galilean moons) • Venus’s phases • Saturn’s rings • Sunspots (blindness)

25. Galileo’s Astronomy Contributions • Moon - craters • Jupiter’s moons (Galilean moons) • Venus’s phases • Saturn’s rings • Sunspots (blindness)

27. Titan

28. Galileo’s Astronomy Contributions • Moon - craters • Jupiter’s moons (Galilean moons) • Venus’s phases • Saturn’s rings • Sunspots (blindness)

30. Galileo’s Astronomy Contributions • Moon - craters • Jupiter’s moons (Galilean moons) • Venus’s phases • Saturn’s rings • Sunspots (blindness)

31. Heliocentric • Helio = Sun • Centric = centered

34. Heliocentric model answers other questions for us

35. Seasons • What do you think causes the seasons? Draw a picture. • When it’s Summer here, what season is it in Europe? • When it’s Summer here, what season is it in South America? • When it’s Summer here, what season is it in Australia?

36. Seasons • 23.5º tilt of the Earth’s axis • How directly the sunlight hits Earth • Length of the day • NOT distance • Distance varies very little, orbit nearly circular • Both Northern and Southern Hemispheres would have the same seasons but they don’t. • Jan 3 actually day we’re closest to Sun

41. Special Days • Vernal Equinox, March 21 • Summer Solstice, June 21 • Autumnal Equinox, September 21 • Winter Solstice, December 21

43. Astrology ≠ Science • Some parts are testable and have been proven WRONG • Other parts are NOT falsifiable (vague descriptions that could be true for anyone) • But, if we think of horoscopes as a flawed model, we can use the flaws to teach science!

44. Ecliptic • The path the Sun appears to take through the sky throughout the year. • The actual path (orbit) the Earth takes around the Sun.

45. Zodiac • The band of constellations that the Sun appears to pass through as it travels along the ecliptic throughout the year

47. Zodiac • The band of constellations that the Sun appears to pass through as it travels along the ecliptic throughout the year • Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, Ophiuchus, Sagittarius, Capricorn, Aquarius, Pisces

49. Other names from Zodiac • Tropics of Cancer / Capricorn • Arctic / Antarctic Circles • First Point in Aries (Vernal Equinox)