Chapter 2 - 2.2

28. The great astronomer of ancient times who summarized and improved a system of circles upon circles to explain the complicated motions of the planets (and published the system in a book now called The Almagest) is:

c. Ptolemy

25. When a planet temporarily moves westward in the sky over the course of several weeks or months (instead of eastward, as it typically does), we call it:

c. retrograde motion

23. How did Eratosthenes measure the size of the Earth?

d. by measuring the height of the Sun in the sky on the same day in two cities at different latitudes

24. Which of the following was NOT done by Hipparchus, the great ancient astronomer?

d. explained retrograde motion

22. Which ancient Greek thinker suggested (long before Copernicus) that the Earth is moving around the Sun?

b. Aristarchus

27. The slow tipping of the Earth's axis in a circle with a period of about 26,000 years is called:

a. precession

29. In Ptolemy's system the planets orbit the Earth and not the Sun. How did the system explain the retrograde motion of planets like Jupiter?

d. the planets moved on a small circle whose center, in turn, circled a point near the Earth

26. Which of the following is NOT a result of the Earth's precession?

d. the stars twinkle when seen from the surface of planet Earth

21. Which of the following is NOT an argument for showing that the Earth must be round:

e. the Sun is seen blocking different constellations in the course of a year