Question 1

The heliocentric model was actually first proposed by

Accepted Answer

Aristarchus.

Question 2

Compared to orbital velocity, escape velocity is about:

Accepted Answer

40% more

Question 3

Given that the planet orbiting the nearby star 51 Pegasi is about 20X larger than the Earth, but 400X more massive, on that world you would weigh:

Accepted Answer

the same as you do here.

Question 4

Jupiter lies about 5 A.U. from the Sun, so at its distance:

Accepted Answer

the Sun\'s gravity is 25 times weaker than its pull on the Earth.

Question 5

Scientists today do not accept the Ptolemaic model because:

Accepted Answer

the work of Tycho and Kepler showed the heliocentric model was more accurate.

Question 6

The most famous prehistoric astronomical observatory is:

Accepted Answer

Stonehenge

Question 7

The Law of Universal Gravitation was developed by:

Accepted Answer

Newton.

Question 8

Galileo found the rotation period of the Sun was approximately

Accepted Answer

a month.

Question 9

According to Kepler\'s third law, the square of the planet\'s period in years is:

Accepted Answer

proportional to the cube of its semimajor axis in A.U.

Question 10

Which of these was NOT seen telescopically by Galileo?

Accepted Answer

stellar parallax

Question 11

Kepler\'s first law worked, where Copernicus\' original heliocentric model failed, because Kepler described the orbits as

Accepted Answer

elliptical, not circular.

Question 12

Combining Newton\'s and Kepler\'s laws, we can weigh the Sun, provided we know:

Accepted Answer

the size of the A.U. and exact length of the year.

Question 13

A circular orbit would have an eccentricity of

Accepted Answer

0.

Question 14

Which of these was a contribution of Newton to astronomy?

Accepted Answer

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

Question 15

How does Kepler\'s First Law refine the Copernican model greatly?

Accepted Answer

Copernicus, like the Greeks, thought all orbits were circular. But when Kepler used elliptical orbits, particularly with Mars and Mercury, the theory fit the actual observations of planetary motion much better than did the old Ptolemaic one.

Question 16

Relate Kepler\'s Second Law to the speeds of the planets.

Accepted Answer

In equal time intervals, the lines that connect each of the planets to the sun must all sweep out equal areas. The longer this line, the slower the planet could move and still sweep out this constant area. Thus more distant planets orbit the Sun slower, and each planet will speed up at perihelion and slow down at aphelion.

Question 17

he force of gravity between two objects:

Accepted Answer

increases with the masses of the bodies, but decreases with the square of the distances between them.

Question 18

Which of these observations of Galileo refuted Ptolemy\'s epicycles?

Accepted Answer

the complete cycle of Venus\' phases

Question 19

Geosynchronous satellites orbit at about four earth radii, where the earth\'s gravitational pull is:

Accepted Answer

1/16 g.

Question 20

Which was a contribution to astronomy made by Copernicus?

Accepted Answer

He laid out the order and relative motion of the known solar system

Question 21

Which of the following was NOT a contribution of Galileo to astronomy?

Accepted Answer

The changing appearance of Saturn\'s rings corresponds to our seasons

Question 22

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

Accepted Answer

The Moon orbits the Earth once a month.

Question 23

According to Copernicus, the retrograde motion for Mars must occur

Accepted Answer

at opposition, when the earth overtakes Mars and passes between Mars and the Sun.

Question 24

The heliocentric model was actually first proposed by:

Accepted Answer

Aristarchus

Question 25

The most accurate Greek attempt to explain planetary motion was the model of:

Accepted Answer

Ptolemy

Question 26

Which concept was NOT a part of Kepler\'s Laws of Planetary Motion?

Accepted Answer

Epicycles are needed to explain the varying brightnesses of the planets.

Question 27

During the eighteenth and nineteenth centuries, attempts to precisely measure the astronomical unit relied largely on rare:

Accepted Answer

transits of the inferior planets across the Sun.

Question 28

Which of these was NOT a telescopic discovery of Galileo?

Accepted Answer

the moons of Saturn

Question 29

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

Accepted Answer

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

Question 30

Orbital speed is the speed with which a planet moves around the Sun. This speed is determined by

Accepted Answer

the mass of both the planet and the Sun and the distance between the two.

Question 31

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

Accepted Answer

- Jupiter has four moons orbiting it. - The Moon has craters, mountain, valleys, and dark flat areas on its surface. - 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. - all of the above is correct

Question 32

Which of these was NOT a part of the original Copernican model?

Accepted Answer

Mercury speeds up at perihelion, and slows down at aphelion.

Question 33

Escape velocity is the speed required to

Accepted Answer

overcome the gravitational pull of an object

Question 34

The Ptolemaic model probably persisted for all these reasons EXCEPT:

Accepted Answer

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

Question 35

According to Copernicus, retrograde motion for Venus must occur around

Accepted Answer

inferior conjunction, when it passes between us and the Sun.

Question 36

A planet whose distance from the Sun is 3 A.U. would have an orbital period of how many Earth-years?

Accepted Answer

square root of 27

Question 37

Upon which point do Copernicus and Kepler disagree?

Accepted Answer

The orbits of the planets are ellipses, with one focus at the Sun.

Question 38

The place in a planet\'s orbit that is closest to the Sun is called

Accepted Answer

perihelion

Question 39

The principal culture that transferred Greek astronomical knowledge to Renaissance Europe was:

Accepted Answer

Islamic.

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