Chapter 2: Discovering the Universe for Yourself © 2015 Pearson Education, Inc.

The sky is divided into 88 zones called: Degrees Tropics Constellations Signs Answer: c) Constellations © 2015 Pearson Education, Inc.

The sky is divided into 88 zones called: Degrees Tropics Constellations Signs Answer: c) Constellations © 2015 Pearson Education, Inc.

A map of the entire sky is called: A meridian A sky finder The celestial sphere The galactic directory Answer: c) The celestial sphere © 2015 Pearson Education, Inc.

A map of the entire sky is called: A meridian A sky finder The celestial sphere The galactic directory Answer: c) The celestial sphere © 2015 Pearson Education, Inc.

Objects are located on the celestial sphere in units of: Miles Kilometers Light years Parsecs Degrees Answer: e) Degrees © 2015 Pearson Education, Inc.

Objects are located on the celestial sphere in units of: Miles Kilometers Light years Parsecs Degrees Answer: e) Degrees © 2015 Pearson Education, Inc.

The angular size of your fist, held at arms length, is about: 1 degree 10 degrees 5 inches 10 inches Answer: b) 10 degrees © 2015 Pearson Education, Inc.

The angular size of your fist, held at arms length, is about: 1 degree 10 degrees 5 inches 10 inches Answer: b) 10 degrees © 2015 Pearson Education, Inc.

When an astronomer describes the altitude of something in the local sky, he or she means: How high above the horizon something is in the sky, in units of miles or kilometers How high above the horizon something is in the sky, in units of degrees The direction toward something–such as north, south, east, or west Answer: b) How high above the horizon something is in the sky, in units of degrees © 2015 Pearson Education, Inc.

When an astronomer describes the altitude of something in the local sky, he or she means: How high above the horizon something is in the sky, in units of miles or kilometers How high above the horizon something is in the sky, in units of degrees The direction toward something–such as north, south, east, or west Answer: b) How high above the horizon something is in the sky, in units of degrees © 2015 Pearson Education, Inc.

When an astronomer describes the azimuth of something in the local sky, he or she means: How high above the horizon something is in the sky, in units of miles or kilometers How high above the horizon something is in the sky, in units of degrees The direction toward something–such as north, south, east, or west Answer: c) The direction toward something–such as north, south, east, or west © 2015 Pearson Education, Inc.

When an astronomer describes the azimuth of something in the local sky, he or she means: How high above the horizon something is in the sky, in units of miles or kilometers How high above the horizon something is in the sky, in units of degrees The direction toward something–such as north, south, east, or west Answer: c) The direction toward something–such as north, south, east, or west © 2015 Pearson Education, Inc.

Directly above Earth's north pole, on the celestial sphere, is The Big Dipper Ursa Major, the great bear The brightest star in the sky The North Star, Polaris C and D Answer: d) The North Star, Polaris © 2015 Pearson Education, Inc.

Directly above Earth's north pole, on the celestial sphere, is The Big Dipper Ursa Major, the great bear The brightest star in the sky The North Star, Polaris C and D Answer: d) The North Star, Polaris © 2015 Pearson Education, Inc.

As seen from North America, stars near Polaris in the sky: Are in the Big Dipper Are seen only in winter Are seen only in summer Never set A and D Answer: d) Never set © 2015 Pearson Education, Inc.

As seen from North America, stars near Polaris in the sky: Are in the Big Dipper Are seen only in winter Are seen only in summer Never set A and D Answer: d) Never set © 2015 Pearson Education, Inc.

What makes Polaris a special star? It is the brightest star in the sky It is always directly overhead, no matter where you are It is near the axis about which the sky turns Its azimuth (direction) is always due north C and D Answer: e) C and D © 2015 Pearson Education, Inc.

What makes Polaris a special star? It is the brightest star in the sky It is always directly overhead, no matter where you are It is near the axis about which the sky turns Its azimuth (direction) is always due north C and D Answer: e) C and D © 2015 Pearson Education, Inc.

Why are different stars seen in different seasons? The tilt of Earth's axis Stars move during the year As Earth orbits the Sun, we see the Sun in front of different constellations Because that's how horoscopes work Precession Answer: c) As Earth orbits the Sun, we see the Sun in front of different constellations © 2015 Pearson Education, Inc.

Why are different stars seen in different seasons? The tilt of Earth's axis Stars move during the year As Earth orbits the Sun, we see the Sun in front of different constellations Because that's how horoscopes work Precession Answer: c) As Earth orbits the Sun, we see the Sun in front of different constellations © 2015 Pearson Education, Inc.

During the year, the Sun appears in front of different groups of stars During the year, the Sun appears in front of different groups of stars. What are these called? Circumpolar stars Circumsolar stars The constellations of the zodiac The tropical constellations Solstice stars Answer: c) The constellations of the zodiac © 2015 Pearson Education, Inc.

During the year, the Sun appears in front of different groups of stars During the year, the Sun appears in front of different groups of stars. What are these called? Circumpolar stars Circumsolar stars The constellations of the zodiac The tropical constellations Solstice stars Answer: c) The constellations of the zodiac © 2015 Pearson Education, Inc.

Why are the Moon and planets seen only in the constellations of the zodiac? The planets all revolve in the same direction around the Sun The planets all orbit in nearly the same plane, and the zodiacal constellations are in that plane. The constellations in the zodiac are the oldest, and the planets have been known from ancient times None of the above reasons Answer: b) The planets all orbit in nearly the same plane, and the zodiacal constellations are in that plane. © 2015 Pearson Education, Inc.

Why are the Moon and planets seen only in the constellations of the zodiac? The planets all revolve in the same direction around the Sun The planets all orbit in nearly the same plane, and the zodiacal constellations are in that plane. The constellations in the zodiac are the oldest, and the planets have been known from ancient times None of the above reasons Answer: b) The planets all orbit in nearly the same plane, and the zodiacal constellations are in that plane. © 2015 Pearson Education, Inc.

When might you see the planet Jupiter in the Big Dipper? Summer Winter Only after midnight Never Answer: d) Never © 2015 Pearson Education, Inc.

When might you see the planet Jupiter in the Big Dipper? Summer Winter Only after midnight Never Answer: d) Never © 2015 Pearson Education, Inc.

When is the Sun directly overhead at noon in North America? March 21 June 21 July 21 Never Answer: d) Never © 2015 Pearson Education, Inc.

When is the Sun directly overhead at noon in North America? March 21 June 21 July 21 Never Answer: d) Never © 2015 Pearson Education, Inc.

When it is summer in the United States, in Australia it is: Winter Summer Spring Fall Answer: a) Winter © 2015 Pearson Education, Inc.

When it is summer in the United States, in Australia it is: Winter Summer Spring Fall Answer: a) Winter © 2015 Pearson Education, Inc.

In summer in the northern hemisphere, what is the Sun's daily motion? Rises in the east, sets in the west Rises north of east, sets south of west Rises north of east, sets north of west Answer: c) Rises north of east, sets north of west © 2015 Pearson Education, Inc.

In summer in the northern hemisphere, what is the Sun's daily motion? Rises in the east, sets in the west Rises north of east, sets south of west Rises north of east, sets north of west Answer: c) Rises north of east, sets north of west © 2015 Pearson Education, Inc.

What causes the seasons? In summer, all of Earth is closer to the Sun In summer, the tilt of Earth's axis makes the part of Earth we are on closer to the Sun In summer, the Sun is up for more hours In summer, the Sun climbs higher in the sky so its rays hit the ground more directly C and D Answer: e) C and D © 2015 Pearson Education, Inc.

What causes the seasons? In summer, all of Earth is closer to the Sun In summer, the tilt of Earth's axis makes the part of Earth we are on closer to the Sun In summer, the Sun is up for more hours In summer, the Sun climbs higher in the sky so its rays hit the ground more directly C and D Answer: e) C and D © 2015 Pearson Education, Inc.

If the tilt of Earth's axis to its orbital plane was 40 degrees, instead of 23 ½, but its distance from the Sun remained the same, what would happen to the seasons? They wouldn't change much They would become less extreme–winter and summer would be more alike They would become more extreme–winter colder and summer warmer All of Earth would get colder All of Earth would get warmer Answer: c) They would become more extreme–winter colder and summer warmer © 2015 Pearson Education, Inc.

If the tilt of Earth's axis to its orbital plane was 40 degrees, instead of 23 ½, but its distance from the Sun remained the same, what would happen to the seasons? They wouldn't change much They would become less extreme–winter and summer would be more alike They would become more extreme–winter colder and summer warmer All of Earth would get colder All of Earth would get warmer Answer: c) They would become more extreme–winter colder and summer warmer © 2015 Pearson Education, Inc.

Why is it generally warmer a month or so after the summer solstice than it is on the solstice itself? It takes time for the Earth to warm up and cool down. The Sun is at a more direct angle overhead a month after the solstice. The days are longer a month after the solstice. It is not, the summer solstice is the hottest time of the year. Answer: a) It takes time for the Earth to warm up and cool down. © 2015 Pearson Education, Inc.

Why is it generally warmer a month or so after the summer solstice than it is on the solstice itself? It takes time for the Earth to warm up and cool down. The Sun is at a more direct angle overhead a month after the solstice. The days are longer a month after the solstice. It is not, the summer solstice is the hottest time of the year. Answer: a) It takes time for the Earth to warm up and cool down. © 2015 Pearson Education, Inc.

The full moon rises at approximately: Midnight Sunset Sunrise 9 or 10 p.m. It rises at different times during the year Answer: b) Sunset © 2015 Pearson Education, Inc.

The full moon rises at approximately: Midnight Sunset Sunrise 9 or 10 p.m. It rises at different times during the year Answer: b) Sunset © 2015 Pearson Education, Inc.

If you were on the Moon, Earth would Show no phases Show phases the same as the moon (when it is full Moon it is full Earth, etc.) Show phases opposite to the Moon (when it is full Moon it is new Earth, etc.) Make a sketch to decide! Answer: c) Show phases opposite to the Moon (when it is full Moon it is new Earth, etc.) © 2015 Pearson Education, Inc.

If you were on the Moon, Earth would Show no phases Show phases the same as the moon (when it is full Moon it is full Earth, etc.) Show phases opposite to the Moon (when it is full Moon it is new Earth, etc.) Make a sketch to decide! Answer: c) Show phases opposite to the Moon (when it is full Moon it is new Earth, etc.) © 2015 Pearson Education, Inc.

Suppose that the Moon was a cube, but everything else was the same–it kept one side facing Earth as it orbited. What would its phases be like? It would not have phases The phases would be just like now The same as now, except square: crescent square, half-square, full square, etc. It would only show "new" and "full" phases Make a sketch to decide! Answer: d) It would only show "new" and "full" phases © 2015 Pearson Education, Inc.

Suppose that the Moon was a cube, but everything else was the same–it kept one side facing Earth as it orbited. What would its phases be like? It would not have phases The phases would be just like now The same as now, except square: crescent square, half-square, full square, etc. It would only show "new" and "full" phases Make a sketch to decide! Answer: d) It would only show "new" and "full" phases © 2015 Pearson Education, Inc.

Why have more people seen an eclipse of the Moon than an eclipse of the Sun? Eclipses of the Sun are much rarer than eclipses of the Moon The shadow of the Moon is smaller than the shadow of Earth Anyone on the night side of Earth can see a total eclipse of the Moon Anyone on the day side of Earth can see a total solar eclipse B and C Answer: e) B and C © 2015 Pearson Education, Inc.

Why have more people seen an eclipse of the Moon than an eclipse of the Sun? Eclipses of the Sun are much rarer than eclipses of the Moon The shadow of the Moon is smaller than the shadow of Earth Anyone on the night side of Earth can see a total eclipse of the Moon Anyone on the day side of Earth can see a total solar eclipse B and C Answer: e) B and C © 2015 Pearson Education, Inc.

What makes the North Star special? It was the first star to be cataloged by ancient astronomers. It lies close to the north celestial pole and is therefore very useful for navigation. It is the brightest star in the entire sky. It is the brightest star in the northern sky. It is visible from both the northern and southern hemispheres. Answer: b) It lies close to the north celestial pole and is therefore very useful for navigation. © 2015 Pearson Education, Inc.

What makes the North Star special? It was the first star to be cataloged by ancient astronomers. It lies close to the north celestial pole and is therefore very useful for navigation. It is the brightest star in the entire sky. It is the brightest star in the northern sky. It is visible from both the northern and southern hemispheres. Answer: b) It lies close to the north celestial pole and is therefore very useful for navigation. © 2015 Pearson Education, Inc.

If you had a very fast spaceship, you could travel to the celestial sphere in about a month. Yes, and the NASA Voyager spacecraft has already done so. Yes, but once such a spacecraft crosses the celestial sphere it can never return. No, the celestial sphere is so far away that, even moving at close to the speed of light, it would take tens of thousands of years to reach. No, the celestial sphere moves away from us at the speed of light so we can never catch up with it. This statement doesn't make sense because the celestial sphere is a concept and not a physical object. Answer: e) This statement doesn't make sense because the celestial sphere is a concept and not a physical object. © 2015 Pearson Education, Inc.

If you had a very fast spaceship, you could travel to the celestial sphere in about a month. Yes, and the NASA Voyager spacecraft has already done so. Yes, but once such a spacecraft crosses the celestial sphere it can never return. No, the celestial sphere is so far away that, even moving at close to the speed of light, it would take tens of thousands of years to reach. No, the celestial sphere moves away from us at the speed of light so we can never catch up with it. This statement doesn't make sense because the celestial sphere is a concept and not a physical object. Answer: e) This statement doesn't make sense because the celestial sphere is a concept and not a physical object. © 2015 Pearson Education, Inc.

I live in the United States, and during my first trip to Argentina I saw many constellations that I'd never seen before. Yes, the skies in Argentina are notable for their clarity, therefore you can see many more stars there than in the United States. Yes, Argentina's southern location affords us a different view of the night sky from what is visible in the United States. No, the skies are exactly the same in both Argentina and the United States. No, the constellations are upside down so they appear different but they are actually the same. This might be true if the visit occurred in the winter when different constellations are visible than in the summer. Answer: b) Yes, Argentina's southern location affords us a different view of the night sky from what is visible in the United States. © 2015 Pearson Education, Inc.

I live in the United States, and during my first trip to Argentina I saw many constellations that I'd never seen before. Yes, the skies in Argentina are notable for their clarity, therefore you can see many more stars there than in the United States. Yes, Argentina's southern location affords us a different view of the night sky from what is visible in the United States. No, the skies are exactly the same in both Argentina and the United States. No, the constellations are upside down so they appear different but they are actually the same. This might be true if the visit occurred in the winter when different constellations are visible than in the summer. Answer: b) Yes, Argentina's southern location affords us a different view of the night sky from what is visible in the United States. © 2015 Pearson Education, Inc.

Last night I saw Mars move westward through the sky in its apparent retrograde motion. Yes, this occurs during certain times of the year when Earth overtakes Mars in its orbit. Yes, this is a well studied phenomenon and its explanation proved a challenge to ancient astronomers. All planets (and stars) move westward because of Earth's rotation, so this is not unusual. No, apparent retrograde motion is only noticeable over many nights, not a single night. No, because Mars lies further from the Sun than Earth, it does not undergo retrograde motion. Answer: d) No, apparent retrograde motion is only noticeable over many nights, not a single night. © 2015 Pearson Education, Inc.

Last night I saw Mars move westward through the sky in its apparent retrograde motion. Yes, this occurs during certain times of the year when Earth overtakes Mars in its orbit. Yes, this is a well studied phenomenon and its explanation proved a challenge to ancient astronomers. All planets (and stars) move westward because of Earth's rotation, so this is not unusual. No, apparent retrograde motion is only noticeable over many nights, not a single night. No, because Mars lies further from the Sun than Earth, it does not undergo retrograde motion. Answer: d) No, apparent retrograde motion is only noticeable over many nights, not a single night. © 2015 Pearson Education, Inc.

If Earth's orbit were a perfect circle, we would not have seasons. True, because Earth would be at the same distance from the Sun throughout its orbit, there would be no summer or winter. True, it is the deviations from a circular orbit that create the seasons. False, the seasons are due to the tilt of Earth's axis, not its distance from the Sun. False, the poles would still be cooler than the equator and seasonal variations would therefore still exist. False, whether circular or not, the seasons depend on the precession of Earth's axis as it orbits the Sun. Answer: c) False, the seasons are due to the tilt of Earth's axis, not its distance from the Sun. © 2015 Pearson Education, Inc.

If Earth's orbit were a perfect circle, we would not have seasons. True, because Earth would be at the same distance from the Sun throughout its orbit, there would be no summer or winter. True, it is the deviations from a circular orbit that create the seasons. False, the seasons are due to the tilt of Earth's axis, not its distance from the Sun. False, the poles would still be cooler than the equator and seasonal variations would therefore still exist. False, whether circular or not, the seasons depend on the precession of Earth's axis as it orbits the Sun. Answer: c) False, the seasons are due to the tilt of Earth's axis, not its distance from the Sun. © 2015 Pearson Education, Inc.

Because of precession, someday it will be summer everywhere on Earth at the same time. Yes, precession will naturally circularize Earth's orbit. Yes, precession will eventually reduce Earth's axis tilt. Yes, precession will make summers occur at the same time, but in what is now the northern spring and southern fall. Yes, but it would take tens of thousands of years, longer than current human history, for this to occur. No, precession only changes the direction in which the North Pole points, and has nothing to do with the seasons. Answer: e) No, precession only changes the direction in which the North Pole points, and has nothing to do with the seasons. © 2015 Pearson Education, Inc.

Because of precession, someday it will be summer everywhere on Earth at the same time. Yes, precession will naturally circularize Earth's orbit. Yes, precession will eventually reduce Earth's axis tilt. Yes, precession will make summers occur at the same time, but in what is now the northern spring and southern fall. Yes, but it would take tens of thousands of years, longer than current human history, for this to occur. No, precession only changes the direction in which the North Pole points, and has nothing to do with the seasons. Answer: e) No, precession only changes the direction in which the North Pole points, and has nothing to do with the seasons. © 2015 Pearson Education, Inc.