Mastering astronomy HW#1(Ch.2)

What do astronomers mean by a constellation? -A constellation is a group of stars related through an ancient story. -A constellation is any random grouping of stars in the sky. -A constellation is a region in the sky as seen from Earth. -A constellation is a group of stars that are all located in about the same place in space.

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

Which of the following celestial objects do not rise in the east and set in the west? (Assume that all of these objects are visible from your location on Earth, and that none of them are circumpolar.) -galaxies -the Sun -the Moon -stars -All of these objects rise in the east and set in the west.

-All of these objects rise in the east and set in the west.

When is the next opportunity to see a total solar eclipse in the United States? -August 12, 2026 -December 4, 2021 -at the next new moon -at the next full moon -April 8, 2024

-April 8, 2024

Which of the following best summarizes the reason we see phases of the Moon? -Half the Moon is always illuminated by the Sun, but the phase we see depends on how much of this half we are looking at from Earth. -Earth casts a shadow into space, and the Moon's phase depends on how much of Earth's shadow is touching the Moon. -The amount of the Moon that is illuminated by sunlight varies as it orbits the Earth, thereby determining the phase that we see

-Half the Moon is always illuminated by the Sun, but the phase we see depends on how much of this half we are looking at from Earth.

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. -The angular distance between those two houses in the distance is 30 degrees. -You can use your outstretched hand against the sky to estimate angular sizes and angular distances. -The angular size of the Sun is about the same as that of the Moon.

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

What is the celestial sphere? -The celestial sphere is a model of how the stars are arranged in the sky relative to our Sun, which is in the middle of the sphere. -The celestial sphere is a model that shows the true locations in space of the Sun and a few thousand of the nearest stars. -It represents a belief in an Earth-centered universe, and hence is no longer considered to have any use. -The celestial sphere is a representation of how the entire sky looks as seen from Earth.

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

Which of the following statements about the celestial sphere is not true? -The Earth is placed at the center of the celestial sphere. -The celestial sphere does not exist physically. -When we look in the sky, the stars all appear to be located on the celestial sphere. -The celestial sphere is another name for our universe

-The celestial sphere is another name for our universe

All the following statements are true. Which one explains the reason that there is not a solar eclipse at every new moon? -The Moon is only about one-fourth as large as Earth in diameter. -The Moon goes through a complete cycle of phases about every 29 1/2 days. -The orbital plane of the Moon is tilted slightly (by about 5 degrees) to the ecliptic plane. -The nodes of the moon's orbit precess with an 18-year period.

-The orbital plane of the Moon is tilted slightly (by about 5 degrees) to the ecliptic plane.

What do we mean when we talk about the Milky Way in our sky? -The spiral-shaped galaxy in which we live. The bright stars of the constellations that lie along the ecliptic in our sky. -The whitish patch of light we see when we look toward the center of the Milky Way Galaxy. -The patchy band of light that outlines the plane of the Milky Way Galaxy as seen from Earth.

-The patchy band of light that outlines the plane of the Milky Way Galaxy as seen from Earth.

Although all the known stars rise in the east and set in the west, we might someday discover a star that will rise in the west and set in the east. Choose the correct explanation why does the statement above make sense (or is clearly true) or does not make sense (or is clearly false). -This statement does not make sense. The stars appear to rise and set because of Earth's rotation. So, during the day, all the stars must move in the same direction. -This statement makes sense. The star appear to rise and set because of the sum of Earth's rotation and changing the seasons. So, in the night of solstice, the North Star could move in the opposite direction to other stars. -This statement makes sense. The North Star itself does not appear to move usually, but sometimes the precession occurs. Precession changes the tilt of Earth's axis and could make the North star set in east or rise in west.This statement does not make sense. -The stars moves because of the Galaxy's rotation around it center. So, during the day, al the stars must move in the same direction.

-This statement does not make sense. The stars appear to rise and set because of Earth's rotation. So, during the day, all the stars must move in the same direction.

About how many stars are visible to the naked eye on a clear, dark night away from city lights? -a couple thousand -several million -a few dozen -a few hundred billion

-a couple thousand

We cannot see a new moon in our sky because __________. -it is obscured by Earth's shadow -a new moon is quite near the Sun in the sky -no sunlight is illuminating the Moon -it is above the horizon during the daytime

-a new moon is quite near the Sun in the sky

What is an annular eclipse? -a type of eclipse that happens once each year -a solar eclipse in which totality lasts for more than 2 minutes -a lunar eclipse in which the Moon turns an eerie red color -a solar eclipse in which the Moon does not appear large enough to fully block the Sun -a lunar eclipse in which the Moon passes only through Earth's penumbra

-a solar eclipse in which the Moon does not appear large enough to fully block the Sun

Stars that are visible in the local sky on any clear night of the year, at any time of the night, are called _____. -circumpolar -celestial -bright -seasonal

-circumpolar

If we have a new moon today when we will have the next full moon? -in about a month -in about two weeks -in about one week -in about six months

-in about two weeks

We describe a location on Earth's surface by stating its __________. -latitude and longitude -meridian and longitude -altitude and direction (or azimuth) -latitude and direction

-latitude and longitude

An angle of 1 arcsecond is _________. about the width of your fist held at arm's length -less than the thickness of a human hair held at arm's length -slightly more than the width of a basketball held at arm's length -about the width of a finger held at arm's length

-less than the thickness of a human hair held at arm's length

Two stars that are in the same constellation -must both have been discovered at about the same time. -may actually be very far away from each other. -must both be part of the same cluster of stars in space.

-may actually be very far away from each other.

Suppose it is full moon. What phase of Earth would someone on the Moon see at this time? -new Earth -full Earth -Earth does not go through phases as seen from the Moon. -first-quarter Earth

-new Earth

In any particular place on Earth, certain constellations are visible in the evening only at certain times of the year because _________. -on any particular night, we can only see stars that are directly opposite (180 degrees away from) the Sun in the sky -during some times of year, some constellations drop below the southern horizon -some constellations are circumpolar -our evening view of space depends on where Earth is located in its orbit around the Sun

-our evening view of space depends on where Earth is located in its orbit around the Sun

How can we describe the location of an object in the local sky? -specifying its latitude and azimuth -specifying its angular size and latitude -specifying its angular size and altitude -specifying its altitude and azimuth

-specifying its altitude and azimuth

The Moon always shows nearly the same face to Earth because __________. -the Moon rotates once in the same amount of time that it takes the Moon to orbit Earth once -sunlight always hits the same face of the Moon -the Moon does not rotate -the Moon rotates once in the same amount of time that it takes Earth to orbit the Sun once

-the Moon rotates once in the same amount of time that it takes the Moon to orbit Earth once

The point directly over your head is called __________. -the zenith -the north celestial pole -the meridian -the North Star

-the zenith

It's 6 a.m. and the Moon is at its highest point in your sky (crossing the meridian). What is the Moon's phase? -first quarter -third quarter -full -new

-third quarter

Why does the local sky look like a dome? -Because we see half of celestial sphere at any time. -Because of the spherical shape of Earth we stay on. -Because the relative thick atmosphere of Earth is above us. -Because of the Earth's rotational and orbital motion.

Because of the Earth's rotational and orbital motion.

gibbous moon

Gibbous means we see more than half the face of the Moon but still less than the whole (full) face of the Moon.

Which of the following correctly describes the meridian in your local sky? -a half-circle extending from your horizon due east, through the north celestial pole, to your horizon due west -a half-circle extending from your horizon due east, through your zenith, to your horizon due west -a half-circle extending from your horizon due north, through your zenith, to your horizon due south -the point directly over your head

a half-circle extending from your horizon due north, through your zenith, to your horizon due south

first quarter moon

half the face of the Moon illuminated at both first quarter and third quarter.

When traveling north from the United States into Canada, you'll see the North Star (Polaris) getting _________. -higher in the sky -lower in the sky -dimmer -brighter

higher in the sky

full shadow (umbra)

the dark, central region of an object's shadow, in which light from the Sun is fully blocked

Partial shadow (penumbra)

the larger, surrounding region of an object's shadow in which light from the Sun is only partially blocked

What is the ecliptic? -the path the Sun appears to trace around the celestial sphere each year -the path traced by the Moon's shadow on Earth during a solar eclipse -a half-circle extending from your horizon due north, through your zenith, to your horizon due south -the Sun's daily path from east to west in our sky

the path traced by the Moon's shadow on Earth during a solar eclipse