Astronomy Chapter 2 Quiz

A circular orbit would have an eccentricity of...

0.

Compared to orbital velocity, escape velocity is about:

40% more.

Which of the following is a contribution to astronomy made by Galileo?

Jupiter has four moons orbiting it. The astronomical telescope can show us far more detail than the eye can. Venus appears almost fully lit when it lies on the far side of the Sun. The Moon has craters, mountain, valleys, and dark flat areas on its surface.

The Law of Universal Gravitation was developed by:

Newton.

What does Kepler's third law imply about planetary motion?

Planets further from the Sun orbit at a slower speed than planets closer to the Sun.

How did Galileo's observations of Venus disprove the Ptolemaic model?

Ptolemy said that the epicycles for both Venus and Mercury were centered on the Earth-Sun line, so they must always lie between us and the Sun, so would always appear as crescents in the telescope. Galileo found Venus went through the entire phase cycle, proving that she revolved completely around the Sun, as predicted by Copernicus in his heliocentric model. (Galileo, through his telescope, perceived that Venus exhibited phases life that of our moon. Phases like these could only be explained if the planet Venus orbited around the Sun. The phases of Venus could not be explained by Ptolemy's Geocentric Model. Galileo knew that the Roman Catholic Church was incorrect. The Earth was not the center of the universe.)

The most famous prehistoric astronomical observatory is:

Stonehenge.

Which of the statements below is part of both the Ptolemaic and Copernican models?

The Moon orbits the Earth once a month.

Which of these was a contribution of Newton to astronomy?

The Sun's gravity is greatest on a planet at perihelion, so the planet must speed up. His differential calculus lets us calculate planetary motions more accurately. Artificial satellites could be put into orbit about the Earth. The Moon pulls as strongly on us as we do on it.

Galileo found the rotation period of the Sun was approximately

a month.

According to Copernicus, the retrograde motion for Mars must occur...

at opposition, when the earth overtakes Mars and passes between Mars and the Sun. at greatest elongation, when Mars can get up to 47 degrees from the Sun.

If the distance between two asteroids is doubled, the gravitational force they exert on each other will...

be one forth as great.

Which of these was NOT seen telescopically by Galileo?

stellar parallax

The Ptolemaic model of the universe:

explained and predicted the motions of the planets with deferents and epicycles.

The force of gravity varies with the...

inverse square of the distance separating the two bodies. product of the two masses.

The Ptolemaic model probably persisted for all these reasons EXCEPT:

it accounted well for Galileo's observations of the phase cycle of Venus.