1. annular eclipse -

• the moon is not close enough to the earth to completely block the sun, so the sun rings the moon

2. autumnal equinox

• when the sun crosses the celestial equator in the fall season, directly over the earth’s equator

3.celestial coordinates

• points on the celestial sphere defined by declination and right ascension

4. celestial equator

• line on the celestial sphere directly over the earth’s equator

5. celestial sphere

• the inside of a sphere where the stars and other objects appear to be fixed

6. constellation -

• a group of stars that appear to form a pattern

7. crescent -

• moon phase that appears as a thin sliver, less surface visible than quarter moon

8. declination -

• degree measure above or below the celestial equator

9. diurnal -

• The daily progression of the Sun, Moon, planets and stars across the celestial sphere

10. eclipse -

• event where one body passes in front of another, blocking the light from the light producing body

11. eclipse season-

• season during which lunar and solar eclipses are possible

12. ecliptic -

• path the Sun follows through the celestial sphere over the course of a year.

13. equinox -

• times of the year when the Sun is directly over the equator

14. full moon -

• all the viewable surface of the Moon is illuminated

15. gibbous -

• more than half of the viewable surface of the Moon is illuminated

16. light-year -

• the distance light travels in one year

17. line of nodes -

• the lines where the plane of the Earth’s orbit and the plane of the Moon’s orbit cross

18. lunar eclipse

• the shadow of the Earth falls on the Moon

19. lunar phase -

• the apparent change of shape of the surface of the Moon as different amounts of the illuminated surface are visible

20. new moon -

• none of the illuminated surface of the Moon is visible

21. north celestial pole -

• point on the celestial sphere directly over north pole

22. partial eclipse -

• not all of the surface of the object is covered by the shadow

23. penumbra -

• the area where all the light from the Sun is not blocked

24. precession -

• the ‘wobble’ of the Earth on its axis

25. quarter moon -

• exactly half of the visible surface of the Moon is illuminated or shaded

26. revolution -

• the movement of any object through its orbit

27. right ascension

• the position of any object in the celestial sphere east or west of a beginning point

28. rotation -

• the spinning of any object on its axis

29. seasons -

• the changes in climatic conditions caused by Earth’s orbit and its tilt on its axis

30. sidereal day -

• a day measured by the position of the stars

31. sidereal month

• a month measured by the position of the Moon in the celestial sphere (measured by the stars)

32. sidereal year -

• a year as measured by the position of the stars

33. solar day -

• a day measured by the position of the Sun in the sky

34. solar eclipse -

• the shadow of the Moon falls on the Earth

35. south celestial pole -

• point on the celestial sphere directly over the south pole

36. summer solstice -

• date when the Sun is as far north of the celestial equator as it will be

37. synodic month -

• a month as measured by the phases of the Moon

38. total eclipse -

• entire surface of the object is blocked,viewers are in the umbra

39. tropical year -

• time it takes Sun to make one complete trip around the celestial sphere on the ecliptic

40. umbra -

• eclipse area where all the light from an object is blocked

41. vernal equinox -

• date in the spring season when the Sun is directly over the equator

42. universe -

• the totality of all space, time, matter, and energy

43. wane -

• when the size of the visible, illuminated surface of the Moon appears to shrink from one date to the next

44. winter solstice -

• date when the Sun is as far south of the celestial equator as it will be

45. wax -

• when the size of the visible, illuminated surface of the Moon appears to grow from one date to the next

46. zodiac -

• the constellations through which the Sun passes over the course of a year

1. Why is it important to astronomical science that the laws of physics as we know them apply equally well throughout the whole universe?

• It’s the only way we can understand and predict occurrences in other areas of the universe.

2. Why does the sun rise in the east and set in the west each day? Does the moon also rise in the east and set in the west? Why? Do the stars do the same? Why?

• The sun, moon, and stars rise in the east and set in the west because the earth rotates from west to east.

3. How many times in your life have you traveled around the sun?

• How old are you in years?

4. Why do we have seasons on earth?• The Earth’s axial tilt causes the Sun’s heat

energy to fall more directly and less directly on certain areas of the Earth at different times of the Earth’s yearly orbit.

5. Why do we see different stars in summer than in winter?• The night time side of the Earth faces

different directions in space at different times of the year.

6. At what phase of the Moon would you expect there to be the most burglaries? Why?

• At new moon it is darkest.

7. If one complete hemisphere of the Moon is always lighted by the sun, why do we see different phases of the moon? • The orbit of the moon around the Earth

causes the Sun’s rays to illuminate different areas of the surface of the Moon. We always see the same side of the Moon, so the fraction of that side that is illuminated changes.

8. What causes a lunar eclipse? A solar eclipse?

• Lunar - Earth between Sun and Moon.

• Solar - Moon between Sun and Earth.

9. What does the fact that there are both annular and total eclipses tell us about the Moon’s distance from the earth?• The distance from the Earth to the Moon

changes.

10. Why aren’t there lunar and solar eclipses every month?• The Moon’s orbital plane is at an angle to

the plane of the Earth’s orbit.

11. From what part’s of the earth is the Pole Star (Polaris) never visible?

• The south pole area.

1. Cosmology –

• the study and descriptions of the universe

• for example, the geocentric model of the solar system (earth at the center) is one cosmology

2. deferent -

the orbit of the planet in the Ptolemaic solar system

3. direct motion -

the normal motion of a planet from west to east from one night to the next

4. epicycle -

• the smaller circle in the orbit of a planet, in addition to the deferent in the Ptolemaic solar system

• explained the retrograde motion of the planets

5. geocentric -

• the model of the solar system (cosmology) with the earth at the center

• everything orbited the earth

6. parallax -

• The apparent shift in position of an object as it is viewed from different positions.

• The lack of observable parallax in the stars was one reason scientists did not believe the earth was moving.

7. Ptolemaic model -

• Best geocentric model of the solar system.

• Consisted of 80 different circles.

8. retrograde motion -

• When a planet is observed to move from east to west from one night to the next.

• The opposite of direct motion.

9. solar system -

• The collection of all objects that orbit the sun.

• In the geocentric system, it was the collection of all objects that orbited the earth.

10. triangulation -

• Using angles, trigonometry, and parallax to determine the distance to an object.

1. What is parallax? Give an example.

• Parallax is the apparent shift in position of an object as it is viewed from different positions.

• When riding in a car, distant objects appear to be moving more slowly than nearby objects.

2. What are epicycles and deferents?

• The deferent is the orbit of a planet; the epicycle is the smaller additional circle.

• Used in the Ptolemaic solar system.

3. Give a brief description of the Ptolemaic model of the universe.

• The earth is at the center, geocentric.

• The planets orbited in deferents.

• The planets also orbited in epicycles to explain retrograde motion. (See question 2.)