Chapter 2 Ancient Astronomy

What problem has precession caused for many of the schools of astrology?

Because of precession, the constellations are no longer lined up with the astrological signs that are named after them; since astrology was set up, the two have slipped one sign apart

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

Aristarchus

How did Eratosthenes measure the size of the Earth?

by measuring the height of the sun in the sky on the same day in two cities at different latitudes

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

precession

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:

retrograde motion

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:

Ptolemy

Based on the scientific and statistical tests of astrological predictions, which of the following statements is the most reasonable?

a. astrology has passed every test with flying colors and scientists now agree that the positions of celestial objects are very important in determining our personalities and future Correct Response b. astrology has not passed any clear scientific or statistical test and, as a result, most scientists are very doubtful that it can predict anything meaningful about our lives c. astrology has passed about half of the tests that have been devised for it, and it is very controversial; about half the scientists think it works, and the other half do not d. no one has ever tested astrology, so it is not possible to say whether it is a useful predictive tool

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

a. compiled a pioneering catalog of the positions of hundreds of stars b. created the system of star magnitudes that we still use today c. discovered that the Earth has a motion called precession Correct Response d. explained retrograde motion

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

a. the Earth wobbles (like a spinning top) with a period of 26,000 years b. where the Earth's axis points in the sky changes over the centuries and millennia c. Polaris will no longer be the North Star in several thousand years Correct Response d. the stars twinkle when seen from the surface of planet Earth

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

a. during an eclipse of the Moon, the shadow of the Earth is always seen to be round b. when ships travel a large distance away, we see their hulls disappear first and their masts disappear last c. the height of the North Star changes as we travel to different latitudes d. photographs of the Earth from space always show a round body Correct Response e. the Sun is seen blocking different constellations in the course of a year

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?

a. the planets were not moving along the ecliptic but all over the celestial sphere b. the planets moved in very elongated ellipses, and their speed in orbit changed radically over the course of a year c. the Sun moved among the planets, and pulled them out of their circular orbits Correct Response d. the planets moved on a small circle whose center, in turn, circled a point near the Earth