AST 101: Chapter 1 Cycles Of The Sky

Order these locations according to the length of shadow cast at noon on an equinox, from longest (top) to shortest (bottom).

1. Quebec, Canada (53 North) 2. Phoenix (33.5 North) 3. Equator

Order the following times of year for the Northern Hemisphere from the hottest (top) to the coldest (bottom).

1. Six weeks after the summer solstice (The hottest time is a bit after the solstice as the land and oceans build up heat.) 2. The summer solstice 3. The spring equinox 4. The winter solstice 5. Six weeks after the winter solstice.

Arrange the times of year based on the position of sunset, from farthest north (top) to farthest south (bottom).

1. Summer solstice 2. A week before the autumnal equinox 3. A week before the spring equinox 4. Winter solstice

Order the events by the length of time each takes, with the longest at the top and the shortest at the bottom.

1. The Earth orbits the Sun once. 2. The Moon Orbits the Earth one time. 3. The Earth rotates once. 4. The Sun rises and later sets.

Order the events by the length of time each takes, with the longest at the top and the shortest at the bottom.

1. The Earth orbits the Sun once. 2. The Sun Moves through one constellation. 3. The Earth rotates once 4. The Sun rises and later sets

How long does it take for the dates of eclipses to repeat?

18.6 years (Yes, As a result of the precession of the Moon's (tilted) orbit, eclipses happen 20 days earlier each year, leading to an 18.6 year cycle.

What time will the waning gibbous Moon (Day 19) be highest in the sky?

3 A.M.

What is a constellation?

An area of the sky for conveniently locating objects A group of stars that form a fixed pattern in the sky.

An __ is a grouping of stars that represents a story or symbol of consequence to a culture and can be handy for locating objects on the celestial sphere.

Constellation

As viewed from Earth, how do the stars appear to move relative tot he north celestial pole?

Counterclockwise around the pole.

Why would an astronomer living 5000 years ago probably recognize constellations visible in our night sky? The patterns ___________.

Do not change appreciably over 5000 years

On the vernal and autumnal equinox, the Sun rises due _______.

East

Select the statements that apply to a lunar eclipse.

Eclipses only occur when the Moon is within 1* of crossing the ecliptic. The Earth's shadow falls on the Moon.

The Sun appears to move along the celestial sphere on a line called the _____.

Ecliptic

Select all the choices that correctly describe equinoxes or solstices.

Equinoxes occur when the sun crosses the celestial equator. During equinoxes, the Earth experiences daytime and nighttime of equal length. The Northern Hemisphere's summer solstice occurs when the Sun is at its northernmost point on the celestial sphere.

True or False: The stars of a constellation are found close together in space.

False The stars appear next to each other as seen from Earth but may be at very different distances from us.

If there is a new Moon today, then what phase will the Moon have in one week?

First Quarter

If the Moon enters it waxing crescent phase tonight, then what lunar phase will you see in approximately two weeks?

Full Waning Gibbous

Why does the Sun rise and set?

It appears to move because of the Earth's rotation.

Why is the concept of the celestial sphere useful to use? (Select all that apply).

It is a convenient way to visualize the motion of celestial bodies. It is a convenient way to describe the location of celestial bodies.

In what ways does the celestial sphere model of the heavens oversimplify reality?

It places the Sun and Plants at approximately the same distance as the stars. It treats all stars as being the same distance. It places the Earth at the center of the universe. It misrepresents the true sizes of stars and planets.

Why is the new moon more difficult to see from Earth than the full moon?

It rises at the same time as The Sun The illuminated Hemisphere of the moon is facing completely away from us

Which parts of the Earth receives 24 hours of daylight for part of the year?

Latitudes above 66.5* N (the Arctic Circle) Latitudes below 66.5* N (The Antarctic Circle)

The figure shows the arrangement of the Earth, Sun, and Moon for a _____.

Lunar Eclipse

A total solar eclipse occurs when the Moon passes between the ___ and the _______.

Moon Sun

What time of day will you see the first-quarter moon rise (cross the horizon)?

Noon

Select all the choices that correctly describe equinoxes or solstices.

On the spring equinox, the Sun is moving from below to above the celestial equator. On a solstice, the Sun is the farthest it gets from the celestial equator.

The sun rises due east and sets due west _____.

Only on an equinox

The tilt of the Moon's orbit shifts a little bit each year, which changes the dates eclipses occur each year. This shift in the orientation of the plane of an orbit is called

Precession

Scientific models are ____.

Representations of nature Used to predict behavior or outcomes typically only useful over specific ranges of sizes or conditions.

One ____ Of a planet is a single trip around the Sun. One ____ is a day.

Revolution Rotation

The celestial sphere describes the position of stars in a way which makes the Universe easier to comprehend. This is a good example of scientific ____.

Scientific Model

The longest day (daytime) of the year occurs on the summer.

Solstice

Which celestial objects rise in the east and set in the west as seen from Earth? (Select all that apply)

Stars near the celestial equator Jupiter The Moon The Sun

The light we see from phases of the Moon comes from _____.

Sunlight reflected by the Moon

One year on Earth is the time it takes for

The Earth to make one revolution around the Sun.

One day on Earth is the time it takes for

The Earth to rotate once

Which of the following is responsible for the Earth's seasons?

The Earth's rotation axis is tilted compared to its orbit.

Usually the entire night side of the Earth can see a lunar eclipse, but solar eclipses are only seen in small areas and happen much faster. This is mostly because ___________.

The Earth's shadow is much bigger than the Moon's

Why is the moon seen as a waning crescent at the location labeled 'A' and not a waxing crescent?

The Moon is moving counterclockwise (as seen in the diagram), and as it gets closer to the Sun, the sunlit portion is turning away from us.

Which of the following can happen during a total lunar eclipse?

The Moon may appear dark red.

Every month, The Moon passes between the Earth and Sun (New Moon) and on the opposite side of the Earth from the Sun (Full Moon). Why don't we see eclipses every month?

The Moon's orbit it tilted.

The Earth's tilt is responsible for which of the following?

The Sun appears to move north and south on the celestial sphere (changes declination) over a year. The North Pole experiences daylight for six months.

Select all the statements that apply to the Sun's path on the winter solstice in the Northern Hemisphere.

The Sun rises in the southeast. The Sun's path across the sky is the shortest all year.

Select all of the statements about the seasons that are correct.

The Sun warms the ground more directly in the summer. There are more daylight hours in the summer than in winter.

Solar eclipses can be hard to observe because ______. (Select all that apply.)

The eclipse path is often over water Totality lasts only a few minutes, so clouds can be a problem The eclipse path is narrow

Select all the reasons why we don't have eclipses every month

The moon may pass above or below the Earth's shadow. The Earth and the Moon have orbits that are tilted compared to each other. The Moon's orbit is tilted 5 degrees from the ecliptic.

Select all that apply to a total solar eclipse.

The sky may become dark as night. The Moon completely covers the Sun.

Select all the choices that describe the path of Sun in the sky if you are at a latitude between 23.5* north and 23.5* south.

The twilight period is shorter than at other latitudes. On some days, the Sun can reach a point directly overhead.

Stars appear as points on the sky, some brighter than others. Why?

Their brightness depends strongly on both how much light a star produces and how far away it is. (Yes, there is a wide range of intrinsic brightness and a wide range of distances, and both are important.

Select all of the following that describe circumpolar stars?

They are found close to one of the celestial poles. They always remain above, or below, the horizon.

Select the statements that apply to solar eclipses

They only occur during new moon. Partial eclipses occur more often than total eclipses. They can be annular eclipses. The Moon's shadow falls on the Earth.

if the moon its waxing crescent phase tonight, then what lunar phase will you see in approximately two weeks?

Waning Gibbous

Which of the following are names of phases of the Moon?

Waning Gibbous Full Moon Waxing Crescent New Moon

Which one of the following is not a complete name of a lunar phase?

Waxing