Chapter 2

Question 1

Boulder, Colorodo : What are your latitude and longitude?

Answer 1

The latitude in Boulder is 40 N and the longitude is about 105∘W.

Question 2

Where does the north (or south) celestial pole appear in your sky?

Answer 2

The north celestial pole appears in Boulder ‘s sky at an altitude of 40 in the direction due north.

Question 3

Is Polaris a circumpolar star in Boulder ‘s sky?

Answer 3

Polaris is circumpolar because it never rises or sets in Boulder ‘s sky.

Question 4

Two stars that are in the same constellation:

Answer 4

may actually be very far away from each other

Question 5

The North Celestial Pole is 35 above your northern horizon. This tells you that you are at:

Answer 5

latitude 35 N

Question 6

Beijing and Philadelphia have about the same latitude but very different longitudes. Therefore, tonight’s night sky in these two places:

Answer 6

Will look about the same

Question 7

Earth’s axis points toward the star Polaris

Answer 7

in winter and spring

Question 8

When it is summer in Australia, the season in the United States is

Answer 8

winter

Question 9

If the Sun rises precisely due east:

Answer 9

it must be the day of either the spring or fall equinox

Question 10

The fact that we always see the same face of the Moon tells us that the Moon

Answer 10

rotates with the same period that it orbits Earth

Question 11

A week after full moon, the Moon’s phase is

Answer 11

third quarter

Question 12

If there is going to be a total lunar eclipse tonight, then you know that:

Answer 12

moon’s phase is full

Question 13

When we see Saturn going through a period of apparent retrograde motion, it means

Answer 13

Earth is passing Saturn in its orbit, with both planets on the same side of the Sun

Question 14

How many arcminutes are in a full circle?

Answer 14

2.16×10^4

Question 15

Polaris is 10 degrees above your horizon. Where are you?

Answer 15

Latitude 10 degrees N

Question 16

We see two stars separated by one degree on the celestial sphere. What can we infer about these stars?

Answer 16

They rise and set at about the same time

Question 17

If Earth’s rotation slowed down so that it completed exactly one rotation about its axis in 100 hours, what would be the typical time interval between sunrise and sunset?

Answer 17

50 hours

Question 18

About how many stars are visible to the naked eye on a clear, dark night away from city lights?

Answer 18

Approxiamitely 2000

Question 19

What is the celestial sphere?

Answer 19

The celestial sphere is a representation of how the entire sky looks as seen from Earth.

Question 20

What is the ecliptic?

Answer 20

the path the Sun appears to trace around the celestial sphere each year

Question 21

What do astronomers mean by a constellation?

Answer 21

A constellation is a region in the sky as seen from Earth

Question 22

As Earth goes around the Sun each year, Earth’s rotation axis in the North points

Answer 22

in the direction of the celestial pole, near Polaris, throughout the year