Exam 1, Part 2

How were ancient astronomers different from modern day astronomers?

Ancient astronomers included religious and esthetic preferences in their model.

A circle is an ellipse with an eccentricity of _________.

0

Rank the following planets from highest average orbital speed (1) to lowest average orbital speed (4). There is one object that is NOT a planet.

1. Mercury 2. Venus 3. Jupiter 4. Saturn

Planets travel at the highest speed when they are close to the Sun and at the lowest speed when they are far away from the Sun.

True

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?

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

When does the Sun cross the celestial equator?

September and March

Your zenith is always directly about your head, unless you are in the southern hemisphere where it is below your feet.

False

In the Heliocentric model, which phase of Venus is never seen from Earth? Use this image as a reference to answer the question.

Gibbous, Half and, Crescent are all seen from Earth.

How was Eratosthenes able to estimate the size of the Earth?

He measured the curvature of the Earth by observing the shadow of a column.

Which of the following objects was not considered a "wanderer" by ancient astronomers ?

Pluto

Which is NOT true about the celestial sphere?

The ecliptic is an extension of Earth's equator.

If you lived in ______________, you would see Polaris _____________ above the horizon.

Washington DC, 38 degrees

Kepler's first law states that the orbits of the planets are __________. He came to this conclusion based on __________.

ellipses, observations of the planets

Which of the following was NOT done by Galileo Galilei?

explaining retrograde motion with the heliocentric hypothesis

What was one of the main reasons that astronomers in the Middle Ages doubted the Geocentric Model?

it failed to accurately predict the positions of the planets

Ancient astronomers knew about precession of the ____________, which means that as time passes, it points at a different ___________.

north celestial pole, star

The image below shows ______________ motion, or when a planet travels ____________ relative to the fixed stars.

retrograde, backwards

Why was stellar parallax NOT observed by ancient astronomers?

stellar parallax is too small to observe without powerful telescopes