ASTRONOMY BASICS: A BRIEF HISTORY

Astronomy is the oldest of the sciences. When Stoneage humans turned to an agrarian way of life and began to settle into communities, their interest must naturally have turned to the "heavens":

The seasons became important; during different times of the year, different stellar patterns appear in the sky. In the spring, Virgo and her accompanying constellations signal the time to prepare the earth, to plant crops, and to be wary of floods. In the fall, Orion rises to indicate time to harvest and to prepare for winter.

The approximate equivalence of the human menstrual cycle and the 30 day orbital period of the Moon which produces lunar phases led to the belief that the heavens, and the Moon in particular, were related to fertility. (What is the Moon's phase right now?)

To early humans facing an uncertain and changeable future, the constancy of the heavens must have suggested perfection and certainly led to deification in many cultures.

We may expect that eclipses would have been especially frightening to early humans. After predicting the seasons, eclipse prediction may have been one of the earliest astronomical activities.

Stonehenge, constructed between 3100-2000 BCE on England's Salisbury Plain, may have been a Stoneage astronomical site (observatory is too strong a word), at least in part. Certainly the alignment of the "heelstone" with the rising Sun on Midsummer's Day (June 21, the Summer Solstice) represents a true astronomical alignment, and many other Megalithic sites have similar alignments. In Stonehenge Decoded, astronomer Gerald Hawkins argued that there exist a large number of astronomical alignments, though further study suggests that many of these are fortuitous.

Cosmologist Fred Hoyle has suggested that Stonehenge may have been used to keep track of the solar-lunar eclipse cycle. Far outside the still partially standing ring of Sarsen Stones is a ring of 56 holes, known as the Aubry holes. Hoyle has noted that movement of a marking stone by 3 positions each time the Sun rose over the heelstone (or by one position three times yearly) would complete a circle in 18.67 years -- approximately the period for the "nodes", the intercepts of the lunar and solar paths in the sky, to complete a cycle. Certainly ritual use of Stonehenge would have been more important that its astronomical functions and much of this interpretation must remain speculation. We may be certain, however, that Stonehenge was indeed constructed by Stoneage humans without the assistance of alien astronauts as suggested in some pseudo-scientific books. Visit the Complete Stonehenge

Eastern observers, notably the Chinese, kept careful track of events in the skies, particularly the appearance of "guest stars" -- comets, novae and other transients. Chinese records of the guest star that we now call Comet Halley can be traced back to 240 BCE and possibly as early as 1059 BCE.

One of the most important Chinese records is of a guest star that was bright enough to be seen during the daytime for nearly a month in the constellation that we call Taurus in July 1054. We believe this to be the supernova explosion that gave rise to the Crab Nebula, and our knowledge of the date of the explosion itself is a very important key in understanding the deaths of massive stars. This event was also chronicled by the Anasazi in Chaco Canyon and by Native Americans elsewhere, but is curiously absent from European records in the Middle Ages.

As the above suggests, Archaeoastronomy is an active and exciting field of research.

Western scientific history begins with the ancient Greek civilization about 600 BCE.