Chapter 1-3

The apparent visual magnitudes of four stars are listed below. Of these four stars which one appears dimmest in the sky?

+2.8

If the apparent visual magnitude of the Sun is -26.5 and that of the full moon is -12.5, what is the light intensity ratio of sunlight to moonlight received at Earth on the day of the full moon?

400,000

Which type of eclipse may be visible to all the people on one side of Earth?

A total lunar eclipse.

At what location on Earth is an observer who has the south celestial pole directly overhead?

At Earth's South Pole (90 degrees South latitude).

At what location on Earth is an observer who has the celestial equator passing through a point directly overhead?

At Earth's equator (0 degrees latitude).

What is responsible for the motion described in the previous question?

Earth's rotation on its axis.

The least extreme tides (Neap Tides) on planet Earth occur during which moon phase?

First Quarter and Third Quarter

Which statement below is the best simple description of the tidal force?

It is a differential gravitational force that acts on the different parts of a body.

Why does the Sun move relative to the stars as described in the previous question?

It is due to Earth revolving around the Sun.

The apparent visual magnitude of star A is 2 and the apparent visual magnitude of star B is 1. Based on this information which statement below must be true?

Light output and distance cannot be determined from a star's apparent visual magnitude alone.

The most extreme tides (Spring Tides) on planet Earth occur during which phase of the Moon?

New and Full

When it is autumn in Asia, what season is it in Antarctica?

Spring

Which statement below best describes the motion of the Moon relative to the stars?

The Moon moves eastward relative to the stars about 13 degrees per day.

How does the Moon's motion relative to the stars compare to the Sun's motion relative to the stars?

The Moon moves faster than the Sun and in the same direction.

Why does the rotational axis of Earth precess?

The Sun and Moon pull on Earth's equatorial bulge.

If the tilt of Earth's axis were to change from 23.5 degrees to 0 degrees what celestial circles would coincide for all observers?

The celestial equator and the ecliptic.

How does one cycle of the Moon's motion relative to the stars compare to one cycle of the Moon's motion relative to the Sun?

The cycle relative to the stars is shorter than the cycle relative to the Sun.

The ocean tides on Earth are primarily due to the influence of what celestial body?

The moon.

Which statement below most accurately describes modern constellations?

They are 88 well defined regions on the celestial sphere.

How many tidal bulges on planet Earth are due to the Moon's gravitational influence?

Two.

If the moon reaches Full phase on May 6, it is at _____ phase on May 17.

Waning Crescent

What changes occur in the Earth-Moon system due to tidal forces?

a. Earth's rate of rotation is slowing. b. The same side of the Moon now always faces Earth. c. The Earth-Moon distance is increasing. ALL of the above

Which of the following is true about the umbra of the Moon's shadow?

a. It is very dark, or a total shadow. c. Its "cone" points away from the Sun. BOTH

Why is amount of solar heating less on a clear day in January at northern latitudes than on a clear day in July?

a. The Sun is above the horizon for less than 12 hours in January in the north. c. At low Sun angles, the received sunlight is spread over a larger surface area. BOTH

A total solar eclipse occurs when the Moon is

a. at New phase. b. near the ecliptic. BOTH

The Milankovitch hypothesis proposes that the ice ages on Earth are due to long-term changes in the amount of seasonal solar heating brought about by

a. changes in the shape of Earth's orbit. b. precession of Earth's rotational axis. c. changes in the tilt angle of Earth's rotational axis. ALL of the above

The precession of Earth's rotational axis causes the location of the

a. north celestial pole and south celestial pole to change. b. vernal equinox and autumnal equinox to change. c. summer solstice and winter solstice to change. ALL of the above

The remaining 48 ancient constellations that we still recognize today are located

at mid and northern celestial latitudes.

What part of the Sun is visible during the "peak" of a total solar eclipse?

b. The chromosphere. c. The corona. BOTH

During a total lunar eclipse the Moon is

b. a reddish color. c. in Earth's umbra. BOTH

A total lunar eclipse occurs when the Moon is

b. near the ecliptic. c. at Full phase. BOTH

What is the most likely Greek letter name of the second brightest star in the constellation Lyra?

beta Lyrae

The five naked-eye planets and three telescopic planets that wander among the stars in the sky are always near the

ecliptic.

During Third Quarter phase, the Moon will rise at about

midnight.

When you observe a star on the celestial equator for a period of a few hours, you notice that it

moves from east to west relative to the horizon.

If you could see the Sun and stars during the daytime for several weeks you would notice that the Sun

moves slowly eastward relative to the stars.

Which pair of apparent visual magnitudes listed below indicates that we receive about 16 times as much visible light from star W than from star X?

mv star W = 2, and mv star X = 5

If the Moon is at one of its nodes it must be

on the Ecliptic.

The time for one cycle of lunar phases is

the same as the time for one cycle of the Moon relative to the Sun.

In one cycle of lunar phases each crescent and gibbous phase has a duration of about one

week.