22.1 Part 1 Note Guide

22.1 Part 1 Note Guide

Early Astronomy

·  Earth is one of ______planets and many smaller ______that orbit the ______

·  The sun is part of a much larger family of perhaps ______stars that make up our galaxy, the ______

·  There are ______of galaxies in the universe

·  A few ______ago scientists thought the Earth was the ______of the universe

Ancient Greeks

·  ______is the science that studies the ______

·  Astronomy deals with the properties of objects in ______and the ______under which the universe operates

·  The “______” of early astronomy (600 B.C.-A.D. 150) was centered in ______

·  The early Greeks used ______arguments to explain natural events but they relied on ______

·  The Greeks used instruments such as the ______to track the positions of the ______

·  The Greeks developed the basics of ______

·  Using these branches of mathematics, they measured the sizes and distance of the ______

·  The Greeks made many astronomical ______

·  The famous Greek philosopher ______(384-322 B.C.) concluded that Earth is ______because it always casts a curved shadow when it passes between the sun and the moon

·  Aristotle’s belief that Earth is round was largely ______in the Middle Ages

·  The first successful attempt to establish the size of Earth is credited to ______(276-194 B.C.)

·  Eratosthenes observed the ______of the noonday sun in two Egyptian cities that were roughly north and south of each other—______(presently Aswan) and ______

·  Finding that the angles differed by ______, or ______of a complete circle, he concluded that the circumference of Earth must be ______the distance between these two cities

·  The cities were ______stadia apart, giving him a measurement of ______stadia

·  Many historians believe the stadia was ______

·  This would make Eratosthenes’ calculation of Earth’s circumference—______kilometers—a measurement very close to the modern circumference of ______kilometers

·  Probably the greatest of the early Greek astronomers was ______(second century B.C.), best known for his ______catalog

·  Hipparchus determined the location of almost ______, which he divided into six groups according to their ______

·  He measured the length of the ______to within minutes of the modern ______and developed a method for predicting the times of ______to within a few hours

Geocentric Model

·  The Greeks believed in the ______

·  They thought that Earth was a ______that stayed motionless at the ______of the universe

·  In the geocentric model, the ______, ______, and the other known planets—Mercury, Venus, Mars, and Jupiter—orbit ______

·  ______the planets was a transparent, hollow sphere on which the ______traveled ______around Earth

·  This is called the ______sphere

·  To the Greeks, all the ______, except ______, appeared to remain in the same relative position to one another

·  These seven ______included the sun, the moon, Mercury, Venus, Mars, Jupiter, and Saturn

·  Each was thought to have a ______around Earth

·  The Greeks were able to explain the apparent movements of ______in space using this model

·  This model, however, was ______

Heliocentric Model

·  ______(312-230 B.C.) was the first Greek to believe in a sun-centered, or ______, universe

·  In the heliocentric model, Earth and the other planets ______

·  Aristarchus used ______to calculate the relative distances from Earth to the ______and from Earth to the ______, but he came up with measurements that were much too small

·  However, he did learn that the sun was many times more ______than the moon and many times ______than Earth

·  Though there was evidence to support the heliocentric model, the Earth-centered view dominated ______thought for nearly ______years

Ptolemaic System

·  Much of our knowledge of Greek astronomy comes from ______

·  In a ______work published in A.D. 141, Ptolemy presented a model of the universe that was called the ______system

·  It accounted for the ______of the planets

·  The ______with which his model was able to predict the motion of the planets allowed it to go unchallenged for nearly ______

·  Just like the Greeks, Ptolemy’s model had the planets moving in ______around a motionless ______

·  However, the motion of the ______against the background of stars seemed odd

·  Each planet, if watched night after night, moves slightly ______among the stars

·  ______, each planet appears to ______, ______direction for a time, and then resume an eastward motion

·  The apparent westward drift is called ______

·  This rather odd apparent motion results from the combination of the motion of ______and the ______motion around the sun