1. The first astronomers created calendars from changes they saw in the Moon. Some ancient people around 5,000 years ago set up large stones to mark the movement of the Sun and other stars. One of those old observatories is Stonehenge in what we now call England.
  2. Ancient natives of North American lined up circles of stones with the Sun and stars to chart the rising Sun and the begining of summers.
  3. In southern Mexico, the Mayans built special buildings to watch the Moon and the planet Venus. They had a calendar by 800 A.D. that was more accurate than the calendar used in Europe.
  4. Ancient Egyptians depended on the Nile River to flood their fields and make it possible to grow crops. They became the first to use a calendar with a 365-day year after their priests discovered that flooding returned about every 365 days.
  5. There are stars and constellations that always appear in Earth’s northern sky. For instance, the Big Dipper is one of those constellations. Ancient sailors used stars and constellations to guide their travels. Polynesians, for example, sailed among the Pacific Ocean islands by watching stars.
  6. To explain why planets seemed to change direction, Ptolemy used old calculations by Hipparchus to understand planetary motion. Hipparchus worked about 130 B.C. and Ptolemy about A.D. 150, which suggestes it took 280 years to come up with the complicated scheme used to predict future positions of planets.
  7. For instance, al-Battani working about 900 A.D. devised new ways of calculating planetary positions. If it hadn’t been for Arabs, Greek science would have been lost.
  8. Astrolabes. “Star-finders” or astrolabes were created by Arab astronomers to solve complicated astronomy problems. One side of an astrolabe contained a detailed star map.

Miscellaneous:

  1. Polaris is today’s north star. It was not in the same position 4,500 years ago as it is today, and would not have helped the pyramid builders.
  2. In July 1054, a star could be seen blazing in the heavens. For three weeks it was so bright it could be seen in daylight. The only reason we know of it today is because Arab, Chinese, Japanese and Native American astronomers noted it. That supernova created what we now call the Crab Nebula. Chinese astronomers wrote about a “guest star” in the constellation Taurus that became four times brighter than Venus and was visible in daylight for 23 days. The yellow colored “guest star” was visible to the naked eye at night for 653 days. Anasazi Indian artists living in Arizona and New Mexico and the Mimbres Indians of New Mexico are thought to have recorded the supernova in their pottery. The Japanese poet Sadiae Fujiwara wrote about the star Zeta Tauri. There are no records of European or Arab observations of the 1054 supernova that have survived to modern times.