Deck 3: Analyzing Scales and Motions of the Universe

Question 1

Greek astronomers knew that Earth was round more than 2000 years ago.

Answer 1

True

Question 2

Nicolaus Copernicus devised the first comprehensive Sun-centered model.

Answer 2

True

Question 3

An astronomical unit (AU)is the distance between Earth and the Moon.

Answer 3

False

Question 4

Eratosthenes' value of Earth's circumference is remarkably close to the modern value.

Question 5

Occam's razor is the idea that the most simple and most straightforward explanation of observations in nature is most likely to be the correct one.

Question 6

Kepler's laws describe planetary orbits,but they can also describe the motion of two stars in a binary star system.

Question 7

Planets do not fall into the Sun during their orbits because they have a sufficiently high velocity moving them forward.

Question 8

The Ptolemic system was the first comprehensive heliocentric model.

Question 9

The word "planet" is derived from a Greek term meaning

A) astrological sign.
B) non-twinkling star.
C) bright nighttime object.
D) wanderer.

Question 10

The average distance between Earth and the Sun is called a "light-year."

Question 11

The force of gravity between two objects is attractive and dependent only on the mass of the larger object,not of the smaller object.

Question 12

Earth pulls harder on the Moon than the Moon pulls on Earth.

Question 13

The farther a moon is from Jupiter,the slower it moves and the longer it takes to orbit around its orbit.

Question 14

As viewed from Earth,the farthest a planet can be observed from the rising Sun is called the greatest eastern elongation.

Question 15

The sidereal period is the time it takes the planet to complete one full orbit of the Sun relative to the very distant background stars.

Question 16

Although Galileo did not invent the telescope,he was the first person to systematically make observations of astronomical objects using the telescope.

Question 17

When a planet is in retrograde,it rises in the west and sets in the east.

Question 18

An orbit with an eccentricity approximately equal to 1 is almost a perfect circle.

Question 19

Humans first determined that Earth is round in the year 1492.

Question 20

In order for an object to have acceleration,a net force must act on that object.

Question 21

Retrograde motion of a planet when viewed from Earth is caused by

A) the relative motions of Sun and planet.
B) its elliptical orbital path.
C) the relative motions of Earth and planet.
D) the inclination of its orbit to the ecliptic plane.

Question 22

The book describing Copernicus's revolutionary work on planetary motions was published

A) in the year of his death.
B) when he was only a young man.
C) when he was in the prime of his life,age 45.
D) in the year that Newton was born.

Question 23

Before the invention of the telescope,the known planets were

A) Mercury,Venus,Mars,Jupiter,and Saturn.
B) Mercury,Venus,Mars,Jupiter,and Uranus.
C) Jupiter,Venus,Neptune,Mars,and Saturn.
D) Mars,Neptune,Jupiter,Mercury,and Venus.

Question 24

In Ptolemy's geocentric theory of the solar system,what name is given to the small circle around which the planet moves while the center of this circle orbits Earth?

A) Celestial equator
B) Ecliptic
C) Deferent
D) Epicycle

Question 25

In the Greek era,it was almost universally believed that

A) the pole star represented the center of the universe,around which Earth and all other objects revolved.
B) Earth was at the center of the universe.
C) the Sun was at the center of the universe.
D) the Milky Way represented the observable universe,with its center as the center of the universe.

Question 26

The center,or fixed point,of the Greek model of the universe was

A) the center of the Galaxy.
B) close to Earth's center.
C) a point midway between Earth and the Sun.
D) the Sun's center.

Question 27

Which of the following statements correctly describes why Copernicus decided that the orbits of Mercury and Venus were smaller than the orbit of Earth?

A) Both planets show a complete cycle of phases,like the Moon.
B) Both planets can sometimes be seen high in our sky at midnight.
C) Both planets occasionally pass through conjunction with the Sun,as seen from Earth.
D) Both planets stay fairly close to the Sun in our sky.

Question 28

Which of the following most closely expresses the principle of Occam's razor as it applies to theoretical explanations of physical phenomena?

A) The theory that has the longest history is the most likely explanation.
B) The theory requiring the most assumptions is the most likely explanation.
C) The newest theory is most likely to be the correct one.
D) The theory requiring the fewest assumptions is the most likely explanation.

Question 29

Nicolaus Copernicus was the first person to

A) develop a mathematical model for a Sun-centered solar system.
B) use a telescope to observe the sky at night.
C) use ellipses to describe the orbits of the planets.
D) describe planetary orbits using the force of gravity.

Question 30

In the geocentric model for the solar system developed by Ptolemy,to what does the word "epicycle" refer?

A) One complete cycle of planetary motions,after which the motions repeat themselves (almost)exactly
B) A small circle around which a planet moves while the center of this circle moves around Earth
C) The large circle (orbit)centered on Earth about which the center of a smaller circle moves while the planet itself is moving along the smaller circle
D) The length of time taken by a planet to go between two successive times when it is farthest from Earth

Question 31

The primary purpose of describing planetary orbits in terms of epicycles and deferents was to account for the

A) generally eastward motion of a planet compared to background stars while the whole sky appeared to move westward.
B) variation of brightness of a planet with time.
C) difference between the sidereal period and the synodic period of a planet.
D) pattern of direct and retrograde motion of a planet as it moved slowly against the background of stars.

Question 32

In Ptolemy's description of the solar system,the deferent is a(n)

A) circular path (around the Sun)along which the center of a planet's epicycle moves.
B) circular path (around Earth)along which the center of a planet's epicycle moves.
C) elliptical path along which a planet moves around the Sun.
D) circular path along which a planet moves while the center of this circular path itself moves in a circle around Earth.

Question 33

Ptolemy developed

A) a heliocentric model for the solar system.
B) the design for Stonehenge.
C) a geocentric model of the solar system.
D) a method for the measurement of Earth's radius.

Question 34

When observing planetary motions from Earth,the phrase "direct motion" refers to

A) the motion of the planet directly toward or away from Earth at certain parts of the planet's orbit.
B) a slow eastward motion of the planet from night to night against the background stars.
C) a slow westward motion of the planet from night to night against the background stars.
D) the apparent westward motion of the planet (along with the Sun,Moon,and stars)across the sky due to the rotation of Earth.

Question 35

The early Copernican system for planetary motions is

A) Earth-centered,with planets,the Sun,and the stars moving in perfect circles.
B) Earth-centered,with planets moving in epicycle patterns around Earth.
C) Sun-centered,with planets moving in perfect circles around the Sun.
D) Sun-centered,with planets moving in elliptical orbits,the Sun being at one focus of the ellipse.

Question 36

The motions of the planets against the background stars in our sky can best be described as

A) regular and uniform eastward motion.
B) general eastward motion interrupted by occasional stationary periods when planets do not appear to move with respect to the stars.
C) regular patterns,with general eastward motion interrupted by periods of westward motion.
D) regular patterns,with general westward motion interrupted by periods of eastward motion.

Question 37

Ptolemy's model for the solar system was

A) Sun-centered,with planets moving in circles around it.
B) Earth-centered,with the Sun,Moon,and planets moving in ellipses in the sky.
C) Sun-centered,with elliptical planetary orbits.
D) Earth-centered,with epicyclic planetary orbits.

Question 38

When observing planetary motions from Earth,the phrase "retrograde motion" refers to

A) the motion of the planet away from Earth during part of its orbit.
B) a slow eastward motion of the planet from night to night against the background stars.
C) the apparent westward motion of the planet (along with the Sun,Moon,and stars)across the sky due to the rotation of Earth.
D) a slow westward motion of the planet from night to night against the background stars.

Question 39

The Greek scientist who developed an early and viable geocentric model of the universe was

A) Brahe.
B) Eratosthenes.
C) Aristotle.
D) Ptolemy.

Question 40

One major contribution of Ptolemy to the development of astronomy was to

A) develop and expand on a mathematical model for the solar system,in which planets move in epicycles around centers that move in circles around Earth.
B) derive a mathematical model for the solar system,in which planets move around the Sun in circular orbits.
C) originate the idea of a geocentric (Earth-centered)cosmology in which planets move in circles around Earth,which was later developed mathematically by Aristarchus.
D) derive a mathematical model for the solar system,in which planets move around Earth in elliptical orbits,moving fastest when closest to Earth.

Question 41

To specify an object's velocity completely,we need to specify

A) its speed.
B) the rate of change of its acceleration.
C) its direction of travel.
D) its speed and direction of travel.

Question 42

How will the illuminated side of Mars appear to us when it is at opposition?

A) Quarter-phase,or half-illuminated
B) Gibbous
C) A full circle
D) Crescent shaped

Question 43

Venus shows changes in angular size and also shows phases similar to those of the Moon.When Galileo first saw these changes,he concluded that

A) Venus orbits the Moon.
B) Venus orbits the Sun.
C) the Moon really orbits Venus,not Earth,after all.
D) Venus,like the Moon,orbits Earth.

Question 44

As seen by an observer on Saturn (or one of its moons),which of the following planets can never pass through inferior conjunction?

A) Jupiter
B) Venus
C) Neptune
D) Earth

Question 45

How many moons of Jupiter did Galileo see?

A) 4
B) 12
C) 1
D) 0

Question 46

Which of the following did Galileo find most significant about his observations of the motions of the large moons of Jupiter?

A) Their motions are counterclockwise (viewed from the north),just like the orbits of the planets.
B) Their orbits were elliptical,just like Kepler predicted.
C) Their orbits obeyed Kepler's second law.
D) The moons farther from Jupiter had longer periods,just as Copernicus had discovered for the planets around the Sun.

Question 47

Galileo's observations suggested to him that the planets revolve around the Sun.This idea was

A) original with Galileo and had not been suggested before.
B) similar to the teachings of the Roman Catholic Church.
C) similar to the ideas of Ptolemy.
D) similar to the ideas of Copernicus.

Question 48

Which one of the following does NOT exhibit retrograde motion when observed from Earth?

A) Mercury
B) Venus
C) The Moon
D) Mars

Question 49

The greatest inaccuracy in Copernicus's theory of the solar system was that he

A) placed the planets in circular orbits.
B) placed the planets on epicycles,the centers of which followed orbits around Earth.
C) did not allow for retrograde motion.
D) assumed that the planets move in elliptical orbits with constant speeds rather than variable speeds.

Question 50

When Jupiter is at opposition,it rises at

A) midnight.
B) noon.
C) sunrise.
D) sunset.

Question 51

What did Galileo see when he observed Venus through his telescope?

A) Venus has phases like the Moon and has its largest angular diameter at gibbous phase.
B) Venus has an angular size that increases and decreases markedly,but it does not show phases (e.g. ,crescent,gibbous).
C) Like the Moon,Venus shows phases,and its angular size remains almost constant.
D) Venus has phases like the Moon and has its largest angular diameter at crescent phase.

Question 52

One of the major contributions of Galileo to the development of modern astronomy was to

A) discover the satellites (moons)of Jupiter.
B) prove that planetary orbits were ellipses.
C) use parallax to prove that Earth moved around the Sun.
D) develop the first mathematical heliocentric model of the solar system.

Question 53

When Mercury is at its farthest distance from Earth,it is at

A) greatest elongation.
B) inferior conjunction.
C) superior conjunction.
D) opposition.

Question 54

How will the illuminated side of Venus appear to us when it is at its greatest eastern elongation?

A) A full circle
B) Half-illuminated,or quarter-phase
C) Gibbous
D) Crescent shaped

Question 55

A planet appears exactly half-lit (looking like the first- or last-quarter moon)when it is

A) in retrograde motion.
B) at inferior conjunction.
C) at greatest elongation.
D) at opposition.

Question 56

A significant contribution of Kepler to our understanding of the solar system was the

A) discovery that Earth orbits the Sun.
B) discovery that planetary orbits are not circular.
C) observation of the phases of Venus.
D) idea of a gravitational force between Earth and the Sun.

Question 57

What did Galileo see when he observed Venus through his telescope?

A) Nothing interesting,because Venus is perpetually cloud-covered
B) Four satellites (moons)orbiting Venus
C) A set of rings
D) Phases like those of the Moon

Question 58

Who was the first astronomer to use a telescope for viewing the sky?

A) Newton
B) Brahe
C) Ptolemy
D) Galileo

Question 59

Which of the following planetary configurations is NOT possible for the planet Mercury?

A) Superior conjunction
B) Greatest elongation
C) Inferior conjunction
D) Opposition

Question 60

Which of the following objects cannot transit (pass in front of)the Sun when viewed from Earth?

A) Mars
B) Venus
C) The Moon
D) Mercury

Question 61

A perfect circle is an ellipse with an eccentricity of

A) zero.
B) one.
C) pi.
D) infinity.

Question 62

Two of Kepler's laws of planetary motion applied to Earth are that the radius vector from the Sun to Earth sweeps out equal areas in equal times,and that Earth's orbit is an ellipse with the Sun at one focus.One consequence of these is that

A) Earth must rotate on its axis.
B) the Sun must rotate on its axis.
C) Earth moves at different orbital speeds at different times of the year.
D) Earth's orbital plane lies in the same plane as the orbits of the other planets.

Question 63

Which of the following statements is TRUE,according to Kepler's third law?

A) The smaller the orbit,the longer it takes for the planet to complete one revolution.
B) The smaller the radius of a planet,the more rapidly it rotates on its axis.
C) The larger the orbit,the longer it takes for the planet to complete one revolution.
D) The time to complete one revolution of its orbit depends on the size or radius of the planet.

Question 64

Acceleration of a moving body is defined as the rate of change of

A) position with time.
B) kinetic energy with time.
C) mass with time.
D) velocity with time.

Question 65

The semimajor axis of an ellipse is

A) the distance from one focus to any point on the circumference of the ellipse.
B) the distance from the center to one side of the ellipse along the shortest diameter of the ellipse.
C) the distance from the center of the ellipse to one end along the largest distance across of the ellipse.
D) half the distance between the foci of the ellipse.

Question 66

Kepler's second law states that a line joining a planet to the Sun

A) sweeps through equal angles in equal times.
B) points in the same direction at all times.
C) sweeps out equal areas in equal times.
D) moves equal distances along the planet's orbit in equal times.

Question 67

At what point in its orbit is a comet closest to the Sun?

A) Perihelion
B) Inferior conjunction
C) Opposition
D) Aphelion

Question 68

The person who first showed that planetary orbits are ellipses was

A) Kepler.
B) Newton.
C) Galileo.
D) Copernicus.

Question 69

A certain object in space is accelerating.From this,we know for certain that

A) its speed is changing.
B) both its speed and its direction of travel are changing.
C) its speed or its direction of travel is changing,but not both.
D) its speed,its direction of travel,or both are changing.

Question 70

Kepler's third law,the harmonic law,provides a relationship between a planet's

A) mass and orbital period.
B) orbital period and length of semimajor axis.
C) physical radius and its time of rotation on its axis.
D) orbital eccentricity and length of semimajor axis.

Question 71

If an object's orbit around the Sun has an eccentricity of 0.8,then the orbit is

A) a straight line.
B) a long,thin ellipse.
C) almost circular.
D) exactly circular.

Question 72

Kepler's first law states that the orbit of a planet about the Sun is a(n)

A) circle with the Sun at the center.
B) ellipse with Earth at the center.
C) ellipse with the Sun at one focus.
D) ellipse with the Sun at the center.

Question 73

To which point in a planetary orbit does the word "perihelion" refer?

A) The "other" focus (the one not occupied by the Sun)
B) The precise center of the orbit
C) The point closest to the Sun
D) The point farthest from the Sun

Question 74

Which of the following statements about an asteroid moving in a circular orbit around the Sun is NOT true?

A) It is moving at a constant speed.
B) It is moving on a flat plane.
C) It is moving at a constant velocity.
D) It is accelerating.

Question 75

The eccentricity of a planet's orbit describes

A) its tilt with respect to the plane of Earth's orbit (the ecliptic plane).
B) its shape compared to that of a circle.
C) its motion at any specific point in its orbit as seen from Earth,that is,whether direct,retrograde,or stationary.
D) the tilt of the planet's spin axis with respect to its orbital plane.

Question 76

How closely do you expect Comet Halley to obey Kepler's laws (particularly P² = a³ with P in years and a in AU)?

A) Never,because it moves independently and is not related to the motions of the planets
B) Very closely only when it is close to the Sun (within Earth's orbital distance)
C) Closely only at very large distances
D) Fairly closely,because it is gravitationally bound to the Sun

Question 77

Acceleration due to gravity on the Moon is

A) significantly smaller than that on Earth.
B) the same as on Earth.
C) twice that on Earth because the Moon is smaller than Earth.
D) zero.

Question 78

According to Kepler's second law,an object in an elliptical orbit around the Sun is traveling fastest when it is at what position?

A) Because it travels at a constant speed throughout its orbit,there is no such position.
B) When it is approaching the Sun,because attraction is greatest over this region
C) Aphelion,farthest from the Sun,because it has to move farther per day at that position
D) Perihelion,the closest point to the Sun

Question 79

In the simplified version of Kepler's third law,P² = a³,the units of the orbital period P and the semimajor axis a of the ellipses must be,respectively,

A) seconds and meters.
B) years and light years.
C) years and meters.
D) years and astronomical units.

Question 80

The Kepler model of the solar system is

A) Sun-centered,with planets moving in circles around it.
B) Earth-centered,with the Sun,Moon,and planets moving in ellipses in the sky.
C) Earth-centered,with planets describing epicycles in the sky.
D) Sun-centered,with elliptical planetary orbits.