Astronomy Midterm Chapter 2

How many arcseconds are in a full circle?

1.296×10^6 arcseconds

The Moon's angular size is about 12∘. What is this in arcseconds?

1800

How many arcminutes are in a full circle?

2.16×10^4 arcminutes

The Moon's angular size is about 12∘. What is this in arcminutes?

30

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?

50 hours

What do astronomers mean by a constellation?

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

What is the celestial sphere?

A representation of how the entire sky looks as seen from Earth

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

Approximately 2,000

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

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

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

Latitude 10 degrees north

Is Polaris a circumpolar star in Charleston 's sky? Choose the correct explanation.

Polaris is circumpolar because it never rises or sets in Charleston 's sky.

When we say the universe is expanding, we mean that:

The average distance between galaxies is growing with time.

Latitude and Longitude of Charleston SC

The latitude in Charleston is 32∘N and the longitude is about 80∘W.

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

The moon's rotation period is the same as its orbital period

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

The north celestial pole appears in Charleston 's sky at an altitude of 32 ∘ in the direction due north.

The fact that nearly all galaxies are moving away from us, with more distant ones moving faster, helped us to conclude that:

The universe is expanding

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

They rise and set at about the same time

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

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

If the Sun rises precisely due east:

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

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

latitude 35∘ N.

Two stars that are in the same constellation:

may actually be very far away from each other.

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

the Moon's phase is full

What is the ecliptic?

the Sun's apparent path along the celestial sphere

In winter, Earth's axis points toward the star Polaris. In spring:

the axis also points toward Polaris.

A week after full moon, the Moon's phase is:

third quarter

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

will look about the same

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

winter