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The Age of Things: Sticks Stones and the Universe

The Age of Things: Sticks Stones and the Universe. Precession, Polaris, and the Pyramids of Egypt. http://cfcp.uchicago.edu/~mmhedman/compton1.html. Last Time: Calendars are the Key to Mayan History. Piedras Negras Stela 3, Drawn by Linda Schele. When calendrical information is unavailable,

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The Age of Things: Sticks Stones and the Universe

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  1. The Age of Things:Sticks Stones and the Universe Precession, Polaris, and the Pyramids of Egypt http://cfcp.uchicago.edu/~mmhedman/compton1.html

  2. Last Time: Calendars are the Key to Mayan History Piedras Negras Stela 3, Drawn by Linda Schele

  3. When calendrical information is unavailable, the age of things can sometimes be determined using astronomical data

  4. Warning! Astrophysict talking about Egyptology!

  5. The Ages of Ancient Egypt The General Structure of Egyptian History Is well established However, the Egyptians did not have a calendar that counted years from a fixed point in the past Years were instead counted From the time the last king came to power.

  6. The Ages of Ancient Egypt To figure out exactly when events occurred in time, we need to know all the kings that ever ruled egypt and how long each one ruled … but existing records are incomplete

  7. The Ages of Ancient Egypt Historical records from each kingdom are abundant enough that events can be well located relative to each other in time. But records from the intermediate periods are sparse, so the length of time occupied by these periods is quite uncertain. Old Kingdom Old Kingdom F.I.P. F.I. P. or? Middle Kingdom Middle Kingdom

  8. The Ages of Ancient Egypt The Middle and New Kingdoms are anchored in time by written texts that mention astronomical events No such text exists for the Old Kingdom, so this period can “float” in time over a few hundred years

  9. In 2000, K.E. Spence suggested the Pyramids themselves could provide the key to anchoring the Old Kingdom in time

  10. The Old Kingdom: The Age of Pyramids The Great Pyramids at Giza

  11. The Three Pyramids of Snofru and the pyramids of the Fifth Dynasty

  12. The pyramids are very accurately aligned with the cardinal directions N W E S

  13. There are slight alignment errors in all the pyramids N W E S

  14. A Curious Pattern in the Pyramids West Side East Side 1/2o East 0o Alignment Error West 1/2o M B R

  15. Timing the Construction of the Pyramids Turin Papyrus Palermo Stone

  16. A Curioser Pattern in the Pyramids 1/2o East Alignment Error (arcminutes) 0o 1/2o West Relative Time (years) (60 arcminutes = 1 degree)

  17. A Curioser Pattern in the Pyramids 1/2o East Alignment Error (arcminutes) 0o 1/2o West Relative Time (years) (60 arcminutes = 1 degree)

  18. A Curioser Pattern in the Pyramids Slope ~ 1/2 degree per century 1/2o East Alignment Error (arcminutes) 0o 1/2o West Relative Time (years) (60 arcminutes = 1 degree)

  19. Precession of the earth Celestial Pole in 2500 BCE Celestial Pole Today

  20. The Precession of the Earth affects the night sky The Northern Sky in 2500 BCE The Northern Sky Today N N Precession causes the stars to move with respect to North at a rate of about 1/2 degree per century

  21. The Night Sky in the Age of the Pyramids N

  22. Using Two Stars to find True North N N

  23. This method has an error that changes with time 2500 BCE 2000 BCE N N

  24. The Sign of the alignment error depends on which star is higher in the sky N N

  25. 1/2o East Alignment Error (arcminutes) 0o 1/2o West Relative Time (years) (60 arcminutes = 1 degree)

  26. The Northern Stars were important to the Egyptians: They were the “indestructable” stars, which never died Ceiling of the tomb of Seti I

  27. Which pair of stars did the Egyptians use?

  28. Which pair of stars did the Egyptians use? Movement of the Celestial Pole The celestial pole moves with respect to the line at a rate that depends on the position of the stars

  29. Different Star-pairs would give different slopes 1/2o East Alignment Error (arcminutes) 0o 1/2o West Relative Time (years) (60 arcminutes = 1 degree)

  30. Only nine pairs of stars give lines that pass through the NCP in a reasonable time

  31. Only one pair of stars are consistent with the observed data Observed Drift Rate in the alignment error

  32. If the Egyptians used these stars, then we now exactly when the pyramids were built 2500 BCE 2400 BCE 1/2o East Alignment Error (arcminutes) 0o 1/2o West Relative Time (years)

  33. Et tu, Djedefre? 2500 BCE 2400 BCE 1/2o East Alignment Error (arcminutes) 0o 1/2o West Relative Time (years)

  34. Et tu, Djedefre? 2500 BCE 2400 BCE 1/2o East Alignment Error (arcminutes) 0o 1/2o West Relative Time (years)

  35. Only one pair of stars are consistent with the observed data Observed Drift Rate in the alignment error

  36. E=mc2 Next Time The Physics of Carbon 14

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