Mayan Astronomy

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Mayan Astronomy

• Mark Bohn
• Jesse Rahikainen

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Who Were the Maya?

• Lived in what is now Central America from around
  1500 B.C. to 900 A.D.
• They had a very advanced society for their time,
  their mathematics and astronomy were far beyond
  most peoples with equivalent technology.
• The religion of the Maya focused on the sky and
  the movement of celestial bodies. A caste of
  astronomer-priests observed the sky and predicted
  how the heavens would move.

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Why did they study the stars?

• The heavenly bodies were seen as gods that had
  influence over every thing that happened.
• By being able to tell what the stars were going
  to do it was supposed that a person would be able
  to tell the future and know the proper times for
  doing various things.

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Cosmology
The universe is layered, nine layers for the
underworld, thirteen for the heavens. Earth was
not the center of the universe but considered
important because it had parts in both the
underworld and heavens.
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Venus

• Considered one of the most important planets by
  the Maya.
• It was tied to warfare and war cults.
• Unlike the ancient Greeks the Maya knew that both
  the morning and evening star were Venus.
• Calculated a Venusian year to be 584 days (it is
  actually 583.92) which they divided into four
  seasons morning star, disappearance at superior
  conjunction, evening star, disappearance at
  inferior conjunction.

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Sun and Moon

• The Sun and Moon were hero twins that defeated a
  great bird pretending to be the Sun.
• Another story puts the Sun and Moon as husband
  and wife with Venus being the Sun's twin brother.
• Mayans had figured a single lunation to be
  29.5302 days (actually 29.53059) and the solar
  year to be 365 days with various accounts of
  higher accuracy.

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Sun and Moon cont.

• Eclipses were considered a portent of doom by the
  Maya and as a result of their great importance
  they were studied carefully.
• Because of this the Maya created extremely
  accurate solar eclipse charts that still work
  today.

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Other Celestial Bodies

• Comets - Predicted the death of nobility.
• Milky Way - Road to the underworld for the
  spirits of the dead.
• Jupiter - Inaugural rituals, ball games, and
  sacrifices were scheduled according to
  this planet.
• Pleiades - Marketplace, would appear in the
  morning sky around the time for
  planting crops.

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How Did They Do It?

• The Maya had the advantage of being near the
  equator, this made it easier to observe the
  movement of the sun giving them a very accurate
  way to count how long a year lasted.
• The astronomer-priests would use nothing more
  than some crude tools, their naked eyes, and lots
  of patience to observe the movement of of the
  heavens.

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How Did They Do It? cont.
The astronomer-priests would build temples that
were very tall so they were able to see into the
distance and then using forked or crossed sticks
and a fixed point on the horizon they would
measure the position of a star or planet.
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How Did They Do It? cont.
They would do this for years and then using this
data, along with some mathematics, would
calculate how long it took for the celestial body
they were observing to make a syndocial cycle.
They would write all this information down into
books called codices.
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How Did They Do It? cont.

• Entire cities were also built to be aligned with
  the stars or cardinal directions. This allowed
  for timing of rituals and agricultural events.
• Buildings were sometimes built so certain things
  would happen only during a few days of the year.
  Such as during the equinoxes at Chichen Itza a
  snake can be seen on the side of the steps of the
  temple.

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How Did They Do It? cont.
They had also figured out a way to take into
account retrograde motion. This is when a planet
appears to stop then change direction in the sky,
the cause of this being the observed planet has a
slower orbit than Earth. There were also rituals
and events associated with planets when they had
stopped or when they were in retrograde.
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Calendars

• One of the greatest accomplishments of the Maya
  were their calendars.
• They had calendars to track the years of most of
  the celestial bodies they had recorded
  information about. Besides just the Moon and Sun
  they had calendars for Venus, Mars, and Jupiter.

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Calendars cont.

• The Venusian calendar was comprised of three
  different calendars.
• Each calendar overlapped the others by a couple
  days, this helped keep them on time. It would
  take 384 years from the day it was created for
  that calendar to become useless.

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Calendars cont.

• There was a ritual calendar that consisted of 260
  days that was made of two sprockets, one numbered
  one to thirteen and the other with the 20 names
  of days.

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Calendars cont.

• The two parts of the calendars acted like gears.
  The smaller one cycling faster than the larger
  one.

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Calendars cont.

• Besides the ritual calendar the Mayans also kept
  track of a 365 day civil calendar.
• This calendar consisted of 18 named months, each
  20 days long. Five days, which were considered
  unlucky, were added to the end to give a total of
  365 days.
• The final day of each month wasn't a coefficient
  of 20 but rather a seating of the month to
  follow. This was justified by the belief that any
  time span is felt before it begins and after it
  ends.

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Calendars cont.

• There is still a third calendar that the Mayans
  used called the long count calendar. This
  calendar was able to identify a unique date in a
  5200 year period. The use of this system
  consisted of counting various time periods much
  like we use weeks and months.

Normally the Mayans used a base 20 number system
when counting
But when counting with the long count calendar
the third place used 18 instead of 20.
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Calendars cont.

• So for an example the number 2.5.10.2 in a base
  20 number system would be 2203520210202
  which is 18202, but using the long count system
  it would be 2202185201810202 which is
  16402. The reason for the difference is unknown,
  but is thought that it was done to make the third
  time period 360 days, which is very close to 365.

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Calendars cont.

• Besides these there was one more cycle that was
  important to the Maya, a creation-destruction
  cycle they believed takes place every few
  thousands of years. They said that we have passed
  through four cycles so far.
• The last cycle ended around August 13, 3114 B.C.
  with a great flood that left the Earth covered in
  darkness. The current age will end on December
  12, 2012 with a great earthquake.