Patsy Ann Todd, age 13of Neffsville Penn
How can they predict a solar eclipse?
Astronomy is the study of the stars in their vast oceans of apace. Like every science, it must begin with observations with masses of notes and records. It took thousands of years to chart the wandering paths of the planet’s But without this information: Galileo could never have proved that the sun is the center of the Solar System. Mankind has always been a stargazer, noting and charting the heavenly parade from generation to generation. Even the modern astronomer depends upon these patient, age‑old records The Chaldeans figured out how to predict the eclipses at least 3,000 years ago, and their system is still accurate.
These stargazers studied the heavens from tall buildings in the deserts of ancient Mesopotamia. They were also interested in numbers. Sixty sixties was a share, or saros. The term saros was also used for a period of time covering 223 full moons, which is 18 years eleven and one third days or 6x585.32 days. This saros of 223 lunar months the Chaldeans noted, was related to the eclipses of the sun and moon.
Their patient records showed that the eclipses follow a pattern. There is a series including 29 lunar eclipses, ten total solar eclipses and 31 partial or annular solar eclipses. The series takes 18 years, eleven and a third days or 223 lunar months • a period of time equal to a saros of the ancient Chaldeans. After this, the series repeats itself with variations.
A modern astronomer can explain why the eclipses follow this pattern. We have a solar eclipse when the moon gets directly between us and the sun and its shadow falls upon the earth. We have a lunar eclipse when the earth passes between the moon and the sun and its shadow falls upon the moon. We do not have eclipses as the moon circles the earth every month because the lunar orbit is irregulars
Eclipses are rare because the moons shadow usually falls short the earth and as a rule the whirling satellite manages to dodge the shadow of the earth.
A new saros repeats the eclipses 120 degrees to the west. After three saroses of 54 years, the series of eclipses has swept clear around the globe. The next series repeats a little north or south of the original positions. The present pattern of solar eclipses is sweeping slowly southward. In 20 saroses, some 1200 years, the pattern of solar eclipses sweeps gradually from pole to pole.
Our astronomers know that the pattern of eclipses is caused by they pattern of movements of the gun, the earth and the moon. The Chaldeans gathered their information about the saros by counting and charting the parade of eclipses through thousands of years, We think they figured the pattern of lunar eclipses first, for this is somewhat easier. Having found the pattern, they could then apply the same system to the solar eclipses.