Archaeoastronomy

Can You Answer the Following Questions?

1. Devise a definition for archaeoastronomy using the two words, which in combination form the new word. Propose a definition which encompasses both meanings.

a. Astronomy: (to the ancients) The interpretation and understanding of the movements of the heavenly bodies.

b. Archaeology: The study of past human life from the material remains which have been left behind.

c. Archaeoastronomy:

2. State two reasons why early humans would have possessed an interest in the night sky.

3. Why would early humans consider the sun, moon and planets important enough to deify? Hint: What made them different from the stars?

MOTIONS OF THE "HOLY" SEVEN

4. What aspects about the moon would have made it more favorable than the sun for its use as the earliest of calendars? Hint: Consider the phase period of the moon (29.5 days) in comparison to the cycle of the year (365 days).

5. Why, in reality, did the moon turn out to be a rather poor calendar in comparison to the sun? Hint: Divide 29.5 into 365.

6. Describe several seasonal effects between summer and winter which are easily observable to anyone who cares to monitor the sun.

7. Using a foresight (a distant mountain or geographical feature) and a backsight (the position from which the observations are being conducted), identify two methods by which the progression of the seasons could be monitored. You may want to sketch your answers.

BASIC DEFINITIONS

8. The spinning of a body about its axis is a good definition for _______________.

9. The motion of a less massive body around a more massive body is termed _______________. Mass is the quantity of material a body possesses.

10. The inclination of the imaginary line about which the earth rotates to the perpendicular of its orbital plane defines this planet's ____________________. The number of degrees measured in this angle, for the earth, is equivalent to _______________.

11. The exact period of time it takes the earth to complete one revolution equals ____________________, while one rotation consumes an interval of ____________________.

UNDERSTANDING THE SEASONS

12. The seasons are the result of the _______________ of the axis of the earth.

13. The earth's axial tilt equals _______________ degrees from the perpendicular to the ecliptic. If the axis of the earth were perpendicular to the ecliptic, a person standing at the same location would NEVER/ALWAYS (circle one) see a change in the noontime altitude of the sun.

14. If the observer, however, is on a tilted planet, the sun's noontime altitude will appear to change. If this change is great enough, _______________ will be the result on that planet.

15. As the earth, revolves around the sun, its axis always ______________________________.

16. Hold a flashlight at various angles to a wall, keeping the distance of the beam to the wall the same. In order to make the light fall over the smallest area, how must the beam be directed toward the wall? ________________________________________________. The more obliquely the beam strikes the wall, the LARGER/SMALLER will be the area illuminated.

17. The energy source of the flashlight is the same, no matter how the beam is directed toward the wall. But the energy falling upon the wall per unit area varies, depending upon the _______________ at which the beam intersects the wall.

18. When the beam strikes the wall at a low angle there is MORE/LESS (circle one) energy per unit area. The opposite is true when the beam is at a higher angle. The same can be said for the angle at which the sun's energy strikes the earth. This is caused by the earth's ____________________.

THE EQUATORIAL GRID

19. The coordinate system which gives navigators the ability to locate objects on the surface of the earth is called _______________ and _______________.

20. _______________ measures distance north and south of the equator while _______________ gauges distance east and west of the prime meridian. These two circles serve as reference circles which allow the establishment of earth's grid system.

21. If the coordinate system of latitude and longitude is projected into space, a new grid system is formed which is very useful to astronomers and is called the ________________ system.

22. Where the equator intersects the sky, a new circle is formed called the _______________. Latitude circles become circles of _______________, while longitude meridians become hours of _________________.

23. Latitude must be designated north or south of the terrestrial equator. Its counterpart in the sky, mentioned in the last problem, is denoted as _______________, depending upon its location with respect to the _______________ equator.

24. Longitude is specified as east or west of the prime meridian. Its sky counterpart is measured eastward from the intersection point of the ___________________ and the _______________. This position is called the ___________________, and it represents the position of the sun at the first moment of _______________.

25. The _______________ represents the path which the sun takes in the sky as the earth revolves around this object. Another way of defining the _______________ is to say that it is the earth's orbital plane projected into space.

26. The number of degrees represented by the inclination of the ecliptic to the celestial equator is equal to _______________.

27. Since the sun moves along the ecliptic, it is not normally crossing the celestial equator. This means that the sun is at some angular measure above or below the celestial equator. The maximum angle which the sun can be above or below the celestial equator is equal to _______________. This corresponds to a declination of ________________ or _______________ respectively.

28. The maximum deviation of the sun above or below the celestial equator occurs on the dates of _______________ and _______________ respectively, and are known as the ___________________ and the ___________________ respectively.

29. The midsummer sun is simply another word for the ____________________ while the midwinter sun represents the ____________________ sun.

30. The total deviation of the sun, from its highest position in the sky at noon (73.5° for Allentown) to it lowest position in the sky at noon (26.5° for Allentown) is equal to _______________. How is this related to the inclination of the earth's axis from the perpendicular to the ecliptic? _________________________________________________________________________

31. If the axis of the earth was inclined 35° from the perpendicular to the ecliptic, the total deviation of the sun from its highest to its lowest position would be _________________ degrees.

32. The inclination of the earth's axis is responsible for what phenomenon which was very keenly watched by the ancients?

33. What significance does 23 ½° have to the earth's grid system of latitude measurement?

a. Tropic of Cancer/Capricorn:

b. Arctic/Antarctic Circle:

34. At the time of the vernal and autumnal equinoxes the sun rises in the direction of due _______________ and sets due _______________. The declination of the sun at these two times of the year is the same and equals _______________.

35. If the sun or any other celestial object is at a positive (northerly) declination, its rising position will always be _______________ of east, while its setting location will always be _______________ of west.

36. Objects with negative declinations will always rise and set to the _______________ of east and west respectively.

37. The celestial equator lies along the declination circle of _______________.

STONEHENGE

38. Where is the location of Stonehenge? State a country and the distance and direction from its principal city.

39. The construction of Stonehenge occurred in _______________ stages. To the nearest 1000 years, the first stage was begun around _______________ while the last stage was completed about _______________.

40. _______________ The massive upright boulders which form the outer circle and inner horseshoe structure of Stonehenge...

41. _______________ The rock cap stones which lie on top of the upright boulders...

42. _______________ The freestanding structures which compose the center horseshoe. They consist of two uprights and a cap stone.

43. _______________ The sun rises over this sarsen at midsummer. The declination of the sun at this time is _______________.

44. _______________ Fifty-six holes were equally spaced in a circle surrounding the outer stone circle of Stonehenge.

45. _______________ A circular trench, about 300 feet in diameter, with the detritus thrown toward the outer stone circle.

46. _______________ The corridor which lead away from the monument in the direction of midsummer sunrise and eventually joined with the Avon River.

47. ___________________ The sun set behind this structure at midwinter when viewed from the center of Stonehenge.

48. ___________________ Sunrise at midwinter was observed to occur at this location.

49. Based upon the aforementioned alignments, Stonehenge could be described as a structure responsible for what practical function.

THE JULIAN AND GREGORIAN CALENDARS

50. The natural units of the calendar are the day, based upon the _______________ of the earth; the month, based upon the _______________ cycle of the moon; and the year, based upon the _______________ of the earth.

51. The period of revolution of the earth with respect to the vernal equinox is called the _______________ year. It is equal to 365.242199 days in length.

52. Almost all calendars were originally based upon the _______________ cycle of the moon. This is understandable because the moon is a bright object and easy to observe, while its phases occur in a much SHORTER/LONGER (circle one) period of time than the interval of a year.

53. All civilizations knew that it was the ______________ which was important to the growing of crops. The solution, to correct for the fact that the phase period of the moon did not divide integrally into the tropical year, was to add extra months to bring the lunar calendar into phase with the tropical year. This process is known as _______________.

54. The roots of our present-day calendar go back to the _______________ Republic which originally used a lunar scheme. The year was composed of 12 months totaling 355 days. Every two to four years an extra month had to be _______________ to bring the calendar back into alignment with the sun. This was always done following the month of February.

55. Because of political mismanagement of the lunar calendar by the Roman priests, ____________________ (a person's name) adopted the concepts of a new solar calendar in 46 BC. It was composed of 12 months and contained 365 days.

56. This calendar, named the ______________ calendar, went into effect on January 1st, 45 BC

57. It was well known by Sosigenes, Caesar's Egyptian astronomer, that the tropical year actually contained about _______________ days. Therefore, each year the earth was given one quarter day less time than it needed to complete its revolution around the sun. The result was that after four years the earth lagged one full day behind the seasons. The problem was solved by intercalating _______________ day every four years at the end of February to bring the earth in step with the sun. All years divisible by four were designated as ____________________.

58. The Julian year had 365.250000 days, while the tropical year had 365.242199 days. In 325 AD the Council of Nicaea fixed the dates when Easter could occur in relation to the sun's crossing of the vernal equinox. Since the repetition of Easter was a function of the tropical year, the date which the sun crossed the vernal equinox, according to the Julian calendar, would gradually over the centuries become EARLIER/LATER (circle one).

59. Eventually the Julian dates for Easter would begin interfering with the fixed date of another important Christian holiday, _______________. Pope _______________ XIII instituted additional calendar reforms in 1582 by dropping 10 days from the year to restore the date of the sun's crossing of the vernal equinox to about March 21st. October 4, 1582 was followed by October 15th. In the matter of leap years, all years divisible by four were still considered leap years, but only century years divisible by _______________ were designated as such. This new calendar was called the _______________ calendar and had 365.242500 days as compared to the tropical year of 365.242199 days. The calendar was now accurate to one day in 3300 years.