Astronomy Ch. 3

It helped them keep track of time and seasons, and it was used by some cultures for navigation. Only a few ancient cultures were good a predicting eclipses, and eclipses play little practical role in civilization.

based on everyday ideas of observation and trial-and-error experiments In that sense, modern science is just a formalization of ideas that innate to human beings.

the seven naked-eye objects that appear to move among the constellations The days got their original names long before the time of the prophets.

used to keep lunar calendars approximately synchronized with solar calendars. This is the saros cycle, not the Metonic cycle.

developed a model of the solar system that made sufficiently accurate predictions of planetary positions to remain in use for many centuries This idea predated him by centuries and later proved to be wrong.

they were the first people known to try to explain nature with models based on reason and mathematics, without resort to the supernatural Many books were indeed lost, but certainly not all other books from all other cultures.

A model designed to explain what we see in the sky while having the Earth located in the center of the universe. The geocentric model developed in ancient Greece and was generally accepted until the time of the Copernican revolution.

An Earth-centered model of planetary motion published by Ptolemy Ptolemy did not have the Sun in the center of his model.

create a detailed model of our solar system with the Sun rather than Earth at the center Newton discovered the law of gravity.

observe planetary positions with sufficient accuracy so that Kepler could later use the data to discover the laws of planetary motion Galileo discovered four moons orbiting Jupiter.

Stellar parallax Stellar parallax, which essentially offers direct proof that the Earth orbits the Sun, was not observed until some two centuries after Galileo.

The focus of an ellipse is always located precisely at the center of the ellipse.

The force of attraction between any two objects decreases with the square of the distance between their centers. This is a direct consequence of Kepler's second law.

make specific predictions that can be tested through observations or experiments A "model" that does not make such predictions cannot be tested and hence is not scientific.

a theory A hypothesis is an educated guess.

Astrology played an important part in the development of astronomy in ancient times, but it is not a science by modern standards. Although many astronomers might consider astrology to be a waste of time today, no serious astronomer would disregard the importance of astrology to the ancient development of astronomy.