Astronomy 1

Front 1

The number of degrees in a full circle is

Back 1

360

Front 2

An arcsecond is a measure of

Back 2

angle

Front 3

How many arcseconds are there in a full circle?

Back 3

360 × 3600

Front 4

If the Moon subtends about ½° and is about 400,000 km from Earth, what is its
approximate diameter?

Back 4

3500 km

Front 5

The diameter of the hydrogen atom, 0.00000000011 meters can be written in scientific
notation as

Back 5

1.1 × 10
−10
m

Front 6

(10 to the power 0) is

Back 6

1

Front 7

What is the approximate angular diameter of the Sun in arcseconds?

Back 7

1860

Front 8

Astronauts on the Moon look back at Earth, a distance of about 400,000 km away. If
the cities of Washington, D.C., and New York are separated by about 300 km, what will
be the angle between them when viewed from the Moon?

Back 8

.04 degrees

Front 9

Consider the angular diameter of the planet Saturn as viewed from Earth. Which of thefollowing is a correct statement about this angular diameter?

Back 9

This value changes. The angular diameter gets larger as the Earth’s distance to Saturn
becomes smaller, and smaller as the Earth’s distance to Saturn becomes larger.

Front 10

The average distance from Earth to the Sun, 149,600,000 km, can be written in
scientific notation as

Back 10

1.496 × 10^8 km

Front 11

By what approximate factor in scientific notation is a human being (height about 2 m)
larger than the nucleus of a hydrogen atom, or proton (diameter about 10 ^
−15
m)?

Back 11

2 × 10^15

Front 12

One astronomical unit, or one AU is defined as the

Back 12

mean distance between the Sun and Earth.

Front 13

Diurnal motion of objects in the sky is caused by the

Back 13

rotation of Earth on its axis.

Front 14

You are observing from the east coast of the United States as a star rises above the
horizon. At this same instant your friend on the west coast will find that this star

Back 14

has not yet risen.

Front 15

What basic pattern do stars seem to trace out in our sky if you watch (or photograph)
stars near the north celestial pole for a period of several hours?

Back 15

circles, with the north celestial pole at the center

Front 16

In late September, Andromeda appears high in the sky at midnight. Six months later
Virgo appears high in the sky at midnight. Where is Andromeda at this time of the year?

Back 16

It is high in the sky at noon and is thus not visible.

Front 17

How much of the overall sky is north of the celestial equator, that is, in the northern
hemisphere?

Back 17

exactly one half

Front 18

The celestial equator is defined as the

Back 18

line in the sky that is perpendicular to Earth's spin axis.

Front 19

Which of the following lines or points is always directly over your head, no matter
where on Earth you go?

Back 19

zenith

Front 20

The ecliptic crosses the celestial equator at

Back 20

two points, known as equinoxes.

Front 21

If you view the sky from twenty degrees north of the equator, the north circumpolar
stars (which do not rise and set) would be

Back 21

the stars within twenty degrees of Polaris, the north star.

Front 22

The apparent path of the Sun across our sky, day by day, throughout the year, is
known as the

Back 22

ecliptic.

Front 23

If we could observe background stars in daylight, how would the Sun appear to move
against this background because of our motion on an orbiting Earth?

Back 23

1° per day, from west to east

Front 24

What is the primary cause of Earth’s seasons?

Back 24

Earth’s rotation axis tilts with respect to the plane of its orbit around the Sun.

Front 25

In the northern hemisphere, summertime occurs when

Back 25

sunlight falls more directly on this hemisphere, heating it more than at other times of
the year.

Front 26

The direction of Earth’s rotation about its axis is the same as the direction of its
revolution about the Sun. How does a solar day compare to a sidereal day on Earth?

Back 26

A solar day is always longer.

Front 27

What does it mean to be “in the tropics”; that is, between the Tropic of Cancer and
the Tropic of Capricorn?

Back 27

The Sun is directly overhead on at least one day of the year.

Front 28

The vernal equinox is that time of the year when the

Back 28

Sun crosses the equatorial plane, or celestial equator, moving north.

Front 29

At the summer solstice in the northern hemisphere, the Sun

Back 29

reaches its highest angle above the southern horizon for the whole year.

Front 30

During one complete year, an observer on the equator would be able to see what
fraction of the overall sky?

Back 30

100%

Front 31

Precession is

Back 31

a very slow conical motion of Earth's axis of rotation.

Front 32

Precession of Earth's axis of rotation is caused by

Back 32

(c) the gravitational pull of the Moon and the Sun on the equatorial bulge of Earth.

Front 33

33. An observer's meridian passes through

Back 33

(a) his zenith and the north and south celestial poles.

Front 34

. If you were going to send a spacecraft to circle the Moon and photograph the entire
far side (the side not visible from Earth), during which lunar phase (as seen from Earth)
would you do the photography?

Back 34

) new moon

Front 35

Why do we see different phases of the Moon?

Back 35

The motion of the Moon in its orbit around Earth causes us to see different amounts
of the sunlit side of the Moon.

Front 36

If the Moon is located at the vernal equinox on the first day of spring, what then is the
phase of the Moon?

Back 36

new

Front 37

When will the first quarter moon rise, approximately?

Back 37

noon

Front 38

If an observer on Earth sees the Moon to be full, than at the same time an observer on
the Moon would see Earth to be at what phase?

Back 38

new

Front 39

You are standing in the middle of the far side of the Moon. Which one of the following statements about what you can and cannot see would be true?

Back 39

You could never see Earth from that location.

Front 40

How does the Moon rotate to keep one face pointed toward Earth at all times?

Back 40

It rotates once per month.

Front 41

The term “synodic month” refers to the

Back 41

time for a complete cycle of lunar phases.

Front 42

The term sidereal month refers to the

Back 42

time over which the Moon completes one orbit around Earth, relative to the stars.

Front 43

During a lunar eclipse the

Back 43

Earth comes between the Sun and the Moon.

Front 44

During a total lunar eclipse (as viewed from Earth) you are standing on the Moon
looking back at Earth. What do you see?

Back 44

Earth appears as a black disk with only a faint glow around the edges.

Front 45

A total lunar eclipse is visible in principle (assuming clear skies everywhere)

Back 45

to everyone in one hemisphere of Earth.

Front 46

The line of nodes of the Moon's orbit is the

Back 46

line of intersection between the Moon's orbit and Earth's orbit (the ecliptic plane).

Front 47

During a solar eclipse, the

Back 47

Moon comes between Earth and the Sun.

Front 48

There is about a 5° angle between the orbit of the Moon and the

Back 48

plane of the ecliptic, or Earth's orbit.

Front 49

Which of the following factors makes it far more likely that a person will have seen a total lunar eclipse than a total solar eclipse?

Back 49

A total lunar eclipse can be seen by people on most of the nighttime side of Earth,
while a specific total solar eclipse can be seen only by people within a narrow strip of
Earth's surface.

Front 50

Assuming clear skies everywhere, a total solar eclipse is visible

Back 50

only to people in a long narrow path much smaller than a hemisphere.

Front 51

Eratosthenes measured the radius of Earth by

Back 51

noting the different angles of the Sun at midday on the same day of the year at
different positions on Earth.

Front 52

How did the ancient Greek astronomer Aristarchus of Samos determine that the
Moon's diameter was about 1/3 that of Earth?

Back 52

by measuring the time it takes the Moon to move through Earth's shadow during a
lunar eclipse

Front 53

What is the cause of an annular eclipse?

Back 53

The Moon's position in its orbit is near apogee, its farthest point from Earth.

Front 54

In about 280 B.C., Aristarchus devised a method of estimating the relative distance of
the Sun and the Moon from Earth by

Back 54

measuring the angle between the Sun and Moon when the Moon is at first or third
quarter.

Front 55

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

Back 55

a slow westward motion of the planet from night to night against the background
stars.

Front 56

Ptolemy's model for the solar system was

Back 56

Earth-centered, with epicyclic planetary orbits.

Front 57

In Ptolemy's description of the solar system, the deferent is

Back 57

a circular path (around Earth) along which the center of a planet's epicycle moves.

Front 58

The early Copernican system for planetary motions is

Back 58

Sun-centered, with planets moving in perfect circles around the Sun.

Front 59

When Mercury is at greatest elongation, what is the angle between the line from Earth
to Mercury and the line from Mercury to the Sun?

Back 59

(b) 90°

Front 60

What is the angle between the line from Earth to Jupiter and the line from Earth to the
Sun when Jupiter is at opposition?

Back 60

180°

Front 61

The synodic period of a planet is the time between

Back 61

successive alignments of Sun, planet, and Earth (e.g., time between successive
oppositions).

Front 62

If a particular asteroid with a circular orbit is seen at opposition every 1.44 years, then
its sidereal period is

Back 62

3.27 years.

Front 63

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

Back 63

Venus has phases like the Moon and has its largest angular diameter at crescent phase.

Front 64

Which of the following statements correctly states the significance of Galileo's
observation that Jupiter has satellites (moons)?

Back 64

It showed that bodies can orbit an object other than Earth.

Front 65

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

Back 65

an ellipse with the Sun at one focus.

Front 66

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

Back 66

perihelion, closest point to the Sun

Front 67

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

Back 67

The larger the orbit, the longer it takes for the planet to complete one revolution.

Front 68

According to Newton's first law,

Back 68

if no force is acting on an object, then the object's speed and direction of travel will
both be constant.

Front 69

Newton's second law states that acceleration produced by a force is

Back 69

inversely proportional to the mass on which the force acts.

Front 70

Which of the following statements is a correct version of Newton's third law?

Back 70

Whenever object A exerts a force on some other object B, B must exert a force of
equal magnitude on A in the opposite direction.

Front 71

The phenomenon of parallax is the

Back 71

change in apparent position of a nearby object as the observer moves.

Front 72

Suppose an asteroid is discovered in an elliptical orbit with a period of exactly one
Suppose an asteroid is discovered in an elliptical orbit with a period of exactly one
year and at perihelion it is 0.5 AU from the Sun. How far from the Sun is this asteroid
when at aphelion?

Back 72

1.5 AU

Front 73

If the mass of the Sun were doubled, the gravitational force on Jupiter due to the Sun
would be

Back 73

twice its present value.

Front 74

If the mass of the Sun were increased by a factor of four, the period of Jupiter’s orbit
around the Sun would be

Back 74

half its present value.

Front 75

Does the Sun or the Moon have a greater effect in causing the tides on Earth?

Back 75

The Moon, because it has a larger difference between pulling on the near side and
pulling on the far side of Earth.