2.10.1: Review Questions
Review Questions
From where on Earth could you observe all of the stars during the course of a year? What fraction of the sky can be seen from the North Pole?
2.
Give four ways to demonstrate that Earth is spherical.
3.
Explain, according to both geocentric and heliocentric cosmologies, why we see retrograde motion of the planets.
4.
In what ways did the work of Copernicus and Galileo differ from the views of the ancient Greeks and of their contemporaries?
5.
What were four of Galileo’s discoveries that were important to astronomy?
6.
Explain the origin of the magnitude designation for determining the brightness of stars. Why does it seem to go backward, with smaller numbers indicating brighter stars?
7.
Ursa Minor contains the pole star, Polaris, and the asterism known as the Little Dipper. From most locations in the Northern Hemisphere, all of the stars in Ursa Minor are circumpolar. Does that mean these stars are also above the horizon during the day? Explain.
8.
How many degrees does the Sun move per day relative to the fixed stars? How many days does it take for the Sun to return to its original location relative to the fixed stars?
9.
How many degrees does the Moon move per day relative to the fixed stars? How many days does it take for the Moon to return to its original location relative to the fixed stars?
10.
Explain how the zodiacal constellations are different from the other constellations.
11.
The Sun was once thought to be a planet. Explain why.
12.
Is the ecliptic the same thing as the celestial equator? Explain.
13.
What is an asterism? Can you name an example?
14.
Why did Pythagoras believe that Earth should be spherical?
15.
How did Aristotle deduce that the Sun is farther away from Earth than the Moon?
16.
What are two ways in which Aristotle deduced that Earth is spherical?
17.
How did Hipparchus discover the wobble of Earth’s axis, known as precession ?
18.
Why did Ptolemy have to introduce multiple circles of motion for the planets instead of a single, simple circle to represent the planet’s motion around the Earth?
19.
Why did Copernicus want to develop a completely new system for predicting planetary positions? Provide two reasons.
20.
What two factors made it difficult, at first, for astronomers to choose between the Copernican heliocentric model and the Ptolemaic geocentric model?
21.
What phases would Venus show if the geocentric model were correct?