Astronomy - Test 1 (Chapter 2)

When are eclipse seasons?

when the nodes of the Moon's orbit are nearly aligned with the Sun .

What is the Saros cycle?

the 18-year cycle over which the pattern of eclipses repeats.

Which of the following never goes in retrograde motion?

the Sun.

The precession of the Moon's nodes means that...

the eclipse seasons occur less than 6 months apart.

Orion is visible on wine evening in the northern hemisphere but not summer evenings because of...

the location of Earth in its orbit.

We can describe a position on Earth's surface by stating its...

Latitude and longitude.

At approximately whaat time would a full Moon be on your meridian?

Midnight.

Which of the following statements about constellations is false?

Most constellations will be unrecognizable hundreds of years from now.

What are Buffalo NY Circumpolar Constellations?

Ursa Minor, Ursa Major, Cassiopeia, Draco, Cepheus.

If the Moon rises around 3 AM, it phase must be...

Waning Crescent.

If Earth's axis had no tilt, would we still have seasons? Why or why not?

We would no longer have seasons, because the Sun's light would hit at the same angle all throughout the year, depending only on where you lived. The slight change in distance between Earth and the Sun during the year would not produce much of an effect.

A million years from now, Alpha Centauri will no longer be the nearest star system to our own.

Stars appear to move randomly in the local solar neighborhood.

The Big Dipper will look different 100,000 years from now than it does today.

Stars appear to move randomly in the local solar neighborhood.

How many arc seconds are in 1 degree?

3,600

How many stars can you see with your naked eye on a clear, moonless night from a dark location?

A few thousand.

Which of the following correctly describes the meridian in your sky?

A half-circle extending your horizon due east, through your zenith, to you horizon due south.

Suppose you live on the Moon. How long is a day (i.e., from sunrise to sunrise)?

A lunar month .

Which of the following best describes the modern definition os a constellation?

A region of the celestial sphere.

What is a circumpolar star?

A star that always remains above your horizon and appears to rotate around the celestial pole.

Describe the celestial equator in our sky.

Answers will vary with latitude; here is a sample answer for 40°N: The celestial equator is a half-circle that stretches from the due east point on the horizon, through an altitude of 50° due south, to the due west point on the horizon.

Where is the north celestial pole in our sky?

Answers will vary with latitude; here is a sample for 40°N: The north celestial pole appears at an altitude of 40°, in the direction due north.

At what altitude and in what direction in your sky does the north or south celestial pole appear?

Answers will vary with your latitude; latitude = altitude of NCP (or SCP in Southern Hemisphere).

What do we have seasons on Earth?

As Earth goes around the sun and Earth's axis remain pointed toward Polaris, the Northern and Southern hemispheres alternately receive more and less direct sunlight.

What causes the apparent retrograde motion of the planets?

As Earth passes another planet, the other planet appears to move backward with respect to the background stars, but the planet's motion does not really change.

Why do we see essentially the same face of the Moon at all times?

Because the Moon's rotational and orbital periods are equal.

Which of the following statements is true?

Both the Northern and Southern hemispheres receive the same amount of sunlight on the equinoxes. The Northern Hemisphere receives the most direct sunlight on the summer solstice.

If it is midnight in New York, it is...

Daytime in Sydney, Australia.

What would you see if you were on the Moon during a lunar eclipse?

During a lunar eclipse, you would see Earth pass in front of the Sun. It would be completely dark where you were.

What would you see if you were on the Moon during a solar eclipse?

During a solar eclipse, you would see a small circular shadow traveling across a portion of Earth's surface.

Suppose you lived on the Moon near the center of the face that we see from Earth. During the phase of full Moon, what phase would you see for Earth? Would it be day or night at your home?

During the full Moon, it would be daytime and you would see the phase of new Earth.

Suppose you lived on the Moon near the center of the face that we see from Earth. During the phase of new Moon, what phase would you see for Earth? Would it be day or night at your home?

During the new Moon, it would be nighttime and you would see the phase of full Earth.

The Moon rises in the east and sets in the west.

Earth rotates once each day.

The stars of Orion's belt rise in the east and set in the west.

Earth rotates once each day.

In which direction does a quarter Moon rise?

East.

A lunar eclipse occurs only when the Moon is new.

FALSE

At midnight it is sometimes possible to observe the crescent Moon on the meridian.

FALSE

Columbus was the first person to discover that Earth is round.

FALSE

It is possible to see the full Moon rising just before sunrise.

FALSE

It is possible to see the third-quarter Moon near the western horizon at sunrise.

FALSE

It is possible to view the Moon in first-quarter phase the day after a total lunar eclipse.

FALSE

Process of Science: Because we do not see stellar parallaxes with our eyes, we conclude that the Earth is at the center of the Solar System.

FALSE

The Milky Way can be seen only from the Northern Hemisphere.

FALSE

The seasons on Earth are caused by its elliptical orbit around the Sun.

FALSE

You can find the tilt of Earth's axis by measuring the angle between your horizon and the North Star.

FALSE

Which of the following is not a phase of the Moon?

Half Moon.

Suppose the distance to the Moon were twice its actual value. Could we still have solar eclipses? If so, what type(s)?

If the Moon were twice its actual distance from us, we would no longer be able to see total solar eclipses because the Moon would not be able to completely cover the surface of the Sun; however, we would still see partial and annular eclipses, although the Moon would not block as much of the Sun during these times.

What makes the North Star, Polaris, special?

It appears very near the north celestial pole.

Which of the following statements about lunar phases is true?

It is possible to have two full Moons during January, but not usually during February.

Which of the following statements about the celestial equator is true at all latitudes?

It represents an extension of Earth's equator onto the celestial sphere.

When we look into the band of light in our sky that we call the Milky Way, we can see distant galaxies? Why or why not?

No, because the stars, gas, and dust of the Milky Way block us from seeing them, however we can see close galaxies.

At approximately what time would a first quarter Moon rise?

Noon

Consider the following statement, and explain whether or not it is sensible: My sign is Ursa Major because the Sun was in Ursa Major when I was born.

Not sensible: The Sun appears only in the constellations of the zodiac-and Ursa Major is not one of these.

You are standing on Earth's equator. Which way is Polaris, the North star?

On the northern horizon.

What effect or effects would be most significant if the Moon's orbital plane were exactly the same as the ecliptic plane?

Solar eclipses would be much more frequent.

Ashen light (or earthshine) is...

Sunlight reflected by Earth that illuminates the "dark" portion of the Moon.

Suppose you lived on the Moon near the center of the face that we see from Earth. At what phase of the Moon would you see sunrise? What phase of Earth would you see at this time?

Sunrise would occur at the Moon's third-quarter phase. You would see Earth in first-quarter phase at this time.

Suppose you lived on the Moon near the center of the face that we see from Earth. At what phase of the Moon would you see sunset? What phase of Earth would you see at this time?

Sunset would occur at the Moon's first-quarter phase. You would see Earth in third-quarter phase at this time.

A solar eclipse occurs only when the Moon is new.

TRUE

If you lived on the Moon, you'd see full Earth when we see new Moon.

TRUE

In South Africa, it's usually quite warm around the time of the winter solstice and quite cool around the time of the summer solstice.

TRUE

Lunar eclipses are more commonly seen than solar eclipses.

TRUE

The Moon and the Sun are approximately the same angular size.

TRUE

Which of the following statements about the celestial sphere is not true?

The "celestial sphere" is just another for our universe.

Why are lunar eclipses more commonly seen than solar eclipses?

The Earth casts a bigger shadow than the Moon.

Why is the Moon not completely invisible (it appears as a very deep red color) to the naked eye during a total lunar eclipse?

The Moon shines through reflected light from the Sun and thus it becomes very dark during a lunar eclipse since the Moon lies within Earth's shadow at this time. However, some sunlight still gets through because it is bent (similar to the way a lens works) by Earth's atmosphere. We see the reflection of this faint light and thus the Moon is not completely invisible. (The bending of light is called refraction and the effect is strongest at long wavelengths. Thus it is most pronounced for red light and the eclipsed Moon appears dark red.)

Which of the following statements about the Moon is true?

The Moon's distance from Earth varies during its orbit.

In addition to the conditions required for any solar eclipse, what must also be true in order for you to observe a total solar eclipse?

The Moon's umbra must touch the area where you are located.

Why is it summer in the Northern Hemisphere when it is winter in the Southern Hemisphere?

The Northern Hemisphere is tilted toward the Sun and receives more direct sunlight.

What is the ecliptic?

The Sun's apparent path along the celestial sphere.

By locating the north celestial pole (NCP) in the sky, how can you determine you latitude?

The altitude of the NCP is the same as your latitude.

Which of the following statements does not use the term angular size or angular distance correctly?

The angular distance between those two bright stars in the sky is about 2 meters.

Which of the following statements about stellar parallax is true?

The closer a star is to us, the more parallax it exhibits.

In the year A.D. 15,000, Vega will be a better north star than Polaris.

The direction of Earth's axis in space precesses with a period of 26,000 years.

Polaris will no longer be the North Star 1,000 years from now.

The direction of Earth's axis in space precesses with a period of 26,000 years.

Describe the meridian in our sky.

The meridian is a half-circle that stretches from the due south point on the horizon, through the zenith, to the due north point on the horizon.

All of the following statements are true. Which one explains the reason why there is not a solar eclipse at every new Moon?

The orbital plane of the Moon is tilted by about 5° to the ecliptic plane.

What conditions are required for a lunar eclipse?

The phase of the Moon must be full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun.

What conditions are required for a solar eclipse?

The phase of the Moon must be new, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun.

What happens during the apparent retrograde motion of a planet?

The planet appears to move westward with respect to the stars over a period of many nights.

Why does the Milky Way appear as a band of light in the sky?

The solar system lies in the outer parts of the thin disk of a spiral galaxy. Thus when we look along the plane of the disk, we see large numbers of stars that, to the naked eye, merge into a band of light. When we look out of the plane of the disk, there are very few stars and the night sky is much darker.

Which of the following statements about parallax is not true?

The technique of stellar parallax was used by Hubble to determine that the Andromeda Galaxy (M 31) is about 2 million light-years away.

Which of the following statements about circumpolar stars is true at all latitudes?

They always remain about your horizon.

Why were ancient peoples unable to detect stellar parallax?

They did not have the ability to measure very small angles.

If the Moon is rising at midnight, the phase of the Moon must be...

Third quarter.

If the moon is setting at noon, the phase of the Moon must be...

Third quarter.

When someone on Earth observes the Moon in the first-quarter phase, someone on the Moon facing the Earth observes Earth in the...

Third-Quarter Earth Phase.

Consider the following statement, and explain whether or not it is sensible: If you lived on the Moon, you'd see full Earth when we see new Moon.

This is true, because at full Moon, Earth lies between the Sun and the Moon. Thus, an observer on the Moon would be looking at the night side of Earth.

Consider the following statement, and explain whether or not it is sensible: Last night I saw Jupiter in the constellation Ursa Major.

This statement does not make sense because Jupiter, like all the planets, is always found very close to the ecliptic in the sky. The ecliptic passes through the constellations of the zodiac, so Jupiter can appear to be only in one of the 12 zodiac constellations-and Ursa Major is not one of these.

Consider the following statement, and explain whether or not it is sensible: If you had a very fast spaceship, you could travel to the celestial sphere in about 100 years.

This statement does not make sense because the celestial sphere is a concept and not a physical object.

Consider the following statement, and explain whether or not it is sensible: When I looked into the dark fissure of the Milky Way with my binoculars, I saw what must have been a cluster of distant galaxies.

This statement does not make sense because we cannot see through the band of light we call the Milky Way to external galaxies; the dark fissure is gas and dust blocking our view.

Consider the following statement, and explain whether or not it is sensible: Although all the known stars appear to rise in the east and set in the west, we might someday discover a star that will appear to rise in the west and set in the east.

This statement does not make sense. The stars aren't really rising and setting, they only appear to rise in the east and set in the west because the Earth rotates.

Consider the following statement, and explain whether or not it is sensible: Last night I saw Mars move westward through the sky in its apparent retrograde motion.

This statement does not makes sense because the apparent retrograde motion is noticeable only over many nights, not during a single night. (Of course, like all celestial objects, Mars moves from east to west over the course of every night.)

Is Polaris a circumpolar star in our sky? Explain.

Yes, for any location in the Northern Hemisphere; no, for any location in the Southern Hemisphere. Polaris is circumpolar because it never rises or sets in our sky. It makes a daily circle, less than 1° in radius, around the north celestial pole.

If the Moon is relatively far from Earth, so that the umbra does not reach Earth, someone directly behind the umbra will see...

an annular eclipse.

If, from the point of view of Earth-bound observers, the Moon is in new Moon phase on a particular day, what phase is Earth as seen from the Moon?

full Earth

If the Moon is setting at 6 AM, the past of the Moon must be...

full.

We can't detect stellar parallax with naked-eye observations. Which of the following would make parallax easier to observe?

increasing the size of Earth's orbit.

If part of the full Moon passes through Earth's umbra, we will see a(n)...

partial lunar eclipse.

Ancient people who knew the Saros cycle could...

predict when an eclipse would happen, but not necessarily what type and where it would be visible.