Pre-Ch 2-1, 2-2, & W2 : Discovering the Universe for Yourself

How many arcminutes are in a full circle?

21600 arcminiutes

Which of the following statements does NOT use the term angular size or angular distance correctly? A. The angular size of the Sun is about the same as that of the Moon. B. You can use your outstretched hand against the sky to estimate angular sizes and angular distances. C. The angular distance between those two bright stars in the sky is about 2 meters. D. The angular distance between those two houses in the distance is 30 degrees.

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

As seen from Earth, the Sun appears to follow the annual path that we call the __________ around the celestial sphere. A. milky way B. south celestial pole C. ecliptic D. constellations E. celestial equator F. north celestial pole

C. ecliptic

We see a ___ only when the Moon is entirely within Earth's partial shadow A. Full shadow (umbra) B. Total solar eclipse C. penumbral lunar eclipse D. Partial solar eclipse E. Partial lunar eclipse F. Total lunar eclipse G. Partial shadow (prenumbra)

C. penumbral lunar eclipse

If you wanted to document the apparent retrograde motion of Mars, you would need to measure and record Mars's ___ over a period of ___. A. one full night B. about 4-6 hours C. position among the constellations D. angular distance from the sun in the sky E. speed as it moves east to west across the sky F. altitude and direction in the sky G. several months H. about 1 week

C. position among the constellations, G. several months

Observations of stellar parallax therefore provide direct evidence that: (Select all that apply.) A. stars move through space B. Earth is smaller than the Sun C. some stars are more distant than others D. Earth orbits the Sun

C. some stars are more distant than others, D. Earth orbits the Sun

We see a ___ only when we are within the Moon's partial shadow A. Full shadow (umbra) B. Total solar eclipse C. penumbral lunar eclipse D. Partial solar eclipse E. Partial lunar eclipse F. Total lunar eclipse G. Partial shadow (prenumbra)

D. Partial solar eclipse

How many arcseconds are in a full circle?

1296000 arcseconds

What is the Moon's angular size in arcseconds?

1800 arcseconds

___ the dark, central region of an object's shadow, in which light from the Sun is fully blocked A. Full shadow (umbra) B. Total solar eclipse C. penumbral lunar eclipse D. Partial solar eclipse E. Partial lunar eclipse F. Total lunar eclipse G. Partial shadow (prenumbra)

A. Full shadow (umbra)

What is special about the June solstice? A. It's the day on which the Northern Hemisphere receives its most direct sunlight. B. It's the day when the Sun has the longest and highest path through the Southern Hemisphere sky. C. It's the longest day of the year for everyone on Earth. D. It's the day when Earth has the greatest axis tilt.

A. It's the day on which the Northern Hemisphere receives its most direct sunlight.

In reality, the Moon's orbit about Earth is tilted (by about 5°) with respect to Earth's orbit about the Sun. As a result, the actual number of solar eclipses that occur each year is approximately _____. A. 0 B. 1 C. 2 D. 12 E. 24

C. 2

What do astronomers mean by a constellation? View Available Hint(s) A. A constellation is a group of stars that are all located in about the same place in space. B. A constellation is any random grouping of stars in the sky. C. A constellation is a region in the sky as seen from Earth. D. A constellation is a group of stars related through an ancient story.

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

If we have a new moon today, when we will have the next full moon? A. in about 1 week B. in about 6 months C. in about a month D. in about 2 weeks

D. in about 2 weeks

The Moon's angular size is about 1/2 degree. What is this in arcminutes?

30 arcminutes

What motion(s) of the Sun might you observe only in the Northern Hemisphere? Select all that may apply. - Sun traces shortest path across the local sky on June Solstice - Sun reaches zenith (altitude 90 degrees) every day at noon - At high latitudes, Sun never rises on December solstice - Sun is above horizon for the longest time on December solstice - Sun rises due east and sets due west on March equinox - Sun reaches highest point in local sky on June solstice - At high latitudes, Sun never sets on December solstice

- Sun reaches highest point in local sky on June solstice - At high latitudes, Sun never rises on December solstice

What motion(s) of the Sun you wont observe anywhere on Earth? Select all that may apply. - Sun traces shortest path across the local sky on June Solstice - Sun reaches zenith (altitude 90 degrees) every day at noon - At high latitudes, Sun never rises on December solstice - Sun is above horizon for the longest time on December solstice - Sun rises due east and sets due west on March equinox - Sun reaches highest point in local sky on June solstice - At high latitudes, Sun never sets on December solstice

- Sun reaches zenith (altitude 90 degrees) every day at noon

What motion(s) of the Sun might you observe everywhere on Earth? Select all that may apply. - Sun traces shortest path across the local sky on June Solstice - Sun reaches zenith (altitude 90 degrees) every day at noon - At high latitudes, Sun never rises on December solstice - Sun is above horizon for the longest time on December solstice - Sun rises due east and sets due west on March equinox - Sun reaches highest point in local sky on June solstice - At high latitudes, Sun never sets on December solstice

- Sun rises due east and sets due west on March equinox

What motion(s) of the Sun might you observe only in the Southern Hemisphere? Select all that may apply. - Sun traces shortest path across the local sky on June Solstice - Sun reaches zenith (altitude 90 degrees) every day at noon - At high latitudes, Sun never rises on December solstice - Sun is above horizon for the longest time on December solstice - Sun rises due east and sets due west on March equinox - Sun reaches highest point in local sky on June solstice - At high latitudes, Sun never sets on December solstice

- Sun traces shortest path across the local sky on June Solstice - Sun is above horizon for the longest time on December solstice - At high latitudes, Sun never sets on December solstice

Which of the following are characteristics of a lunar eclipse? - occurs when the moon comes directly between Earth and the Sun - can occur only at a full moon - can be seen by anyone on Earth's night side at the same time - can occur only at new moon - occurs when Earth's shadow falls on the Moon - occurs when the Moon's shadow falls on the Earth - occurs when the Moon is on the direct opposite side of the Earth from the Sun - can be seen only along a relatively narrow path on Earth

- occurs when Earth's shadow falls on the Moon - can be seen by anyone on Earth's night side at the same time - occurs when the Moon is on the direct opposite side of the Earth from the Sun - can occur only at a full moon

Which of the following are characteristics of a solar eclipse? - occurs when the moon comes directly between Earth and the Sun - can occur only at a full moon - can be seen by anyone on Earth's night side at the same time - can occur only at new moon - occurs when Earth's shadow falls on the Moon - occurs when the Moon's shadow falls on the Earth - occurs when the Moon is on the direct opposite side of the Earth from the Sun - can be seen only along a relatively narrow path on Earth

- occurs when the moon comes directly between Earth and the Sun - occurs when the Moon's shadow falls on the Earth - can be seen only along a relatively narrow path on Earth - can occur only at new moon

What conditions must exist for a lunar eclipse to occur? Select all that apply. A. it must be full moon B. the Moon must be passing through Earth's orbital plane C. it must be new moon D. it must be near the time of the summer or winter solstice E. the Moon must be below Earth's orbital plane

A, B

Which of the following accurately describe an eclipse season? Select all that apply. A. During an eclipse season, there will be a lunar eclipse at full moon. B. During an eclipse season, there will be a solar eclipse at new moon. C. An eclipse season occurs when the nodes of the Moon's orbit are lined up with Earth and the Sun. D. An eclipse season is a time when your local weather is favorable for viewing an eclipse. E. An eclipse season is the time from one day before an eclipse until one day after it.

A, B, C

Which of the following statements about phases of the Moon are true? Select all that apply. A. the time between new moon and full moon is about two weeks B. at new moon, the half of the Moon facing the Sun is fully illuminated C. if it's new moon, the Moon will rise in the middle of the day D. if it is full moon, the Moon will rise around sunset E. the time between first-quarter moon and third-quarter moon is about a month F. at new moon, we see only the "night" side of the Moon G. at new moon, the Moon's entire surface is engulfed in darkness

A, B, D, F

What conditions must exist for a solar eclipse to occur? Select all that apply. A. the Moon must be passing through Earth's orbital plane B. the Moon must be above Earth's orbital plane C. it must be near the time of the spring or fall equinox D. it must be full moon E. it must be new moon

A, E

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

A. April 8, 2024

What is really happening in space during the periods when we see Mars going through apparent retrograde motion? A. Earth is passing by Mars in its orbit around the Sun. B. Earth and Mars are moving in opposite directions around the Sun. C. Mars is moving along its orbit in the opposite direction from the way it usually moves. D. Mars and the Sun both appear to be in the same constellation as viewed from Earth.

A. Earth is passing by Mars in its orbit around the Sun.

The Sun rises and sets each day because A. Earth rotates once each day B. its position seems to change because of stellar C. parallax D. it orbits Earth once each day E. it undergoes retrograde motion each day

A. Earth rotates once each day

As you saw in Part D, stellar parallax exists only because Earth orbits the Sun. Therefore, if the ancient Greeks had measured stellar parallax, they would have known that their belief in an Earth-centered universe was wrong. Why didn't the ancient Greeks measure stellar parallax? A. Even for the nearest stars, parallax angles are too small to measure with the naked eye. B. The Greeks thought all the stars were the same distance away, residing on a celestial sphere. C. Some Greeks actually did measure it, but they did not understand the importance of their measurements. D. Their belief in an Earth-centered universe meant that they did not expect parallax, and therefore did not look for it.

A. Even for the nearest stars, parallax angles are too small to measure with the naked eye.

If you are located in the Northern Hemisphere, which of the following correctly describes a relationship between the sky and your location? A. The altitude of the north celestial pole equals your latitude. B. The altitude of the celestial equator equals your latitude. C. The altitude of the north celestial pole equals your longitude. D. The longitude of the north celestial pole is circumpolar, and therefore crosses your zenith at the meridian.

A. The altitude of the north celestial pole equals your latitude.

How would a star's parallax change as its distance from Earth increases? A. The parallax shift decreases as the star's distance from Earth increases. B. The parallax shift does not change; it is independent of the star's distance from Earth. C. The parallax shift increases as the star's distance from Earth increases.

A. The parallax shift decreases as the star's distance from Earth increases.

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

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

Eclipse seasons do not occur exactly twice a year. Instead, they occur slightly more often, coming about 173 days apart (which is a bit less than the roughly 182 to 183 days that make up 6 months). Why do they do this, rather than occurring exactly twice each year? A. because the line of nodes gradually moves around the Moon's orbit B. because the Moon's cycle of phases is not exactly one month long C. because the length of a year is not exactly 12 cycles of lunar phases D. because Earth's axis slowly precesses in an approximately 26,000 year cycle

A. because the line of nodes gradually moves around the Moon's orbit

Based on their inability to detect stellar parallax, the ancient Greeks concluded that _________. A. either Earth is the center of the universe or stars are extremely far away B. Earth must be the center of the universe C. the stars must be extremely far away D. they lacked the technology necessary for detecting stellar parallax

A. either Earth is the center of the universe or stars are extremely far away

About what time is it for the person who sees the third quarter moon at its highest point? A. sunrise B. sunset C. midnight D. noon

A. sunrise

What conditions must exist for a solar eclipse to occur? Select all that apply. A. the Moon must be passing through Earth's orbital plane B. the Moon must be above Earth's orbital plane C. it must be full moon D. it must be near the time of the spring or fall equinox E. it must be new moon

A. the Moon must be passing through Earth's orbital plane, E. it must be new moon

Approximately how often do eclipse seasons occur? A. twice a year B. once a year C. once a month D. twice a month E. four times a year

A. twice a year

Which of the following statements are true about summer compared to winter? Select all that apply. A. At a given time of day, shadows are longer in summer. B. Temperatures tend to be warmer in summer. C. You have more daylight and less darkness in summer. D. The Sun follows a longer and higher path through your sky in summer.

B, C, D

What is the basic reason that we have seasons on Earth? A. Earth's distance from the Sun varies over the course of each year. B. Earth's axis is tilted relative to the ecliptic plane. C. Earth's orbit is not quite a perfect circle. D. The amount of energy put out by the Sun varies over the course of each year.

B. Earth's axis is tilted relative to the ecliptic plane.

Which of the following best summarizes the reason we see phases of the Moon? A. Earth casts a shadow into space, and the Moon's phase depends on how much of Earth's shadow is touching the Moon. B. 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. C. The amount of the Moon that is illuminated by sunlight varies as it orbits the Earth, thereby determining the phase that we see.

B. 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 best describes why we have seasons on Earth? A. The tilt of Earth's axis causes the Northern Hemisphere to be closer to the Sun than the Southern Hemisphere in summer, and visa versa in winter. B. The tilt of Earth's axis causes different portions of Earth to receive more or less direct sunlight at different times of year. C. Earth's elliptical orbit means we are closer to the Sun and therefore receive more intense sunlight at some times of year than at others. D. The varying speed of Earth in its orbit around the Sun gives us summer when we are moving fastest and winter when we are moving slowest.

B. The tilt of Earth's axis causes different portions of Earth to receive more or less direct sunlight at different times of year.

We see a ___ only when we are within the Moon's full shadow A. Full shadow (umbra) B. Total solar eclipse C. penumbral lunar eclipse D. Partial solar eclipse E. Partial lunar eclipse F. Total lunar eclipse G. Partial shadow (prenumbra)

B. Total solar eclipse

Consider a time when Mars is in the middle of one of its periods of apparent retrograde motion. During this time, Mars appears ___ in our night sky and crosses the meridian around ___. A. noon B. brightest C. highest D. dimmest E. dawn F. dusk G. midnight H. lowest

B. brightest, G. midnight

Stars that are visible in the local sky on any clear night of the year, at any time of the night, are called _________. View Available Hint(s) A. seasonal B. circumpolar C. bright D. celestial

B. circumpolar

Part complete Suppose you live at a mid-latitude in the Southern Hemisphere (such as in Australia, New Zealand, Chile, or South Africa). When will you have 12 hours of daylight and 12 hours of darkness? A. on the March equinox only B. on both the March and September equinoxes C. on the June solstice only D. on both the June and December solstices E. on the December solstice only

B. on both the March and September equinoxes

We see a ___ when the moon is only partially within the full shadow A. Full shadow (umbra) B. Total solar eclipse C. penumbral lunar eclipse D. Partial solar eclipse E. Partial lunar eclipse F. Total lunar eclipse G. Partial shadow (prenumbra)

E. Partial lunar eclipse

The Sun reaches the zenith (directly overhead) at midday ___________. Select all the options that make the statement true. A. everywhere in the Southern Hemisphere on the December solstice B. on the equator only on the March and September equinoxes C. on the Arctic circle (66.5°N) on the June solstice D. on the equator every day E. everywhere in the Northern Hemisphere on the June solstice F. everywhere within the tropics (between latitudes 23.5°N and 23.5°S) on two dates each year

B. on the equator only on the March and September equinoxes, F. everywhere within the tropics (between latitudes 23.5°N and 23.5°S) on two dates each year

Which of the following are the correct times for a third quarter moon? A. rise: about 9am; set: about 9pm B. rise: about midnight; set: about noon C. rise: about 3am; set: about 3pm D. rise: about noon; set: about midnight E. rise: about sunrise; set: about sunset

B. rise: about midnight; set: about noon

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

B. the path the Sun appears to trace around the celestial sphere each year

The combination of the 173-day period between eclipse seaons and the Moon's approximately 29 1/2 - day cycle of phases leads to what we call the saros cycle, which lasts about 18 years, 11 1/3 days. Which of the following accurately describe something about the saros cycle? A. If there is a solar eclipse in your home town today, there will be another solar eclipse in your home town 18 years, 11 1/3 days from now. B. If there is a solar eclipse in your home town today, there will be a lunar eclipse in your home town 18 years, 11 1/3 days from now. C. If there is a solar eclipse in your home town today, there will be a solar eclipse in a different part of the world 18 years, 11 1/3 days from now. D. If there is a solar eclipse any place today, there will not be another solar eclipse anywhere in the world for another 18 years, 11 1/3 days.

C. If there is a solar eclipse in your home town today, there will be a solar eclipse in a different part of the world 18 years, 11 1/3 days from now.

What happens to Earth's axis as we orbit around the Sun over the course of each year? A. It sweeps out a cone while remaining at a 23½° tilt, so that it sometimes points toward Polaris and sometimes toward other stars. B. It wobbles back and forth, so that the tilt varies between 0° and 23½°. C. It remains pointed in the same direction at all times.

C. It remains pointed in the same direction at all times.

Why will total solar eclipses no longer be possible after about 600 million years from now? A. The Sun will have died. B. Earth will have moved closer to the Sun, so that the Sun will look much larger in our sky. C. The Moon will have moved too far from Earth for it to fully block the Sun. D. The Moon will have shrunk in size too much for it to fully block the Sun.

C. The Moon will have moved too far from Earth for it to fully block the Sun.

What happens during the apparent retrograde motion of a planet? A. The planet moves backward in its orbit around the Sun. B. The planet moves backward through the sky over the course of a night. C. The planet appears to move westward with respect to the stars over a period of many nights. D. The planet rises in the west and sets in the east. E. The planet moves through constellations that are not part of the zodiac.

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

As discussed in the video, parallax measurements allow us to calculate distances to stars for which parallax is detectable. Suppose you have a telescope capable of measuring parallax shifts of a particular amount (for example, 0.001 arcsecond). Which of the following locations for the telescope would allow you to measure distances to the most distant stars? A. a telescope on the Moon B. a telescope placed on the same orbit of the Sun as Earth, but on the opposite side of the Sun C. a telescope on Mars D. a telescope orbiting Earth E. a telescope on a clear mountaintop on Earth the location would not affect the maximum distance to which the telescope could detect parallax

C. a telescope on Mars

Suppose that instead of being inclined to Earth's orbit around the Sun, the Moon's orbit was in the same plane as Earth's orbit around the Sun. In this hypothetical situation, approximately how many solar eclipses would occur each year? A. 0 B. 1 C. 2 D. 12 E. 24

D. 12

A total solar eclipse can only happen during what lunar phase? A. waning gibbous B. first quarter C. full D. new

D. new

During the time that a planet is in its period of apparent retrograde motion, _________. A. the planet moves backwards (clockwise as viewed from above Earth's north pole) in its orbit of the Sun B. the planet appears to rise in the west and set in the east, rather than the usual rising in the east and setting in the west C. the planet is getting closer to the Sun in its orbit D. over many days or weeks, the planet moves westward relative to the stars, rather than the usual eastward relative to the stars

D. over many days or weeks, the planet moves westward relative to the stars, rather than the usual eastward relative to the stars

Which of the following celestial objects do NOT rise in the east and set in the west, as viewed from the Earth? (Assume that all of these objects are visible from your location on Earth, and that none of them are circumpolar.) A. stars B. the Sun C. galaxies D. the Moon E. All of these objects rise in the east and set in the west.

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

Why were ancient peoples unable to detect stellar parallax? A. They did not observe for long enough periods of time. B. They did not look for it. C. They did detect it, but they rejected the observations. D. They could not see distant stars. E. They did not have the ability to measure very small angles.

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

Where does the Sun remain above the horizon all day (never setting) on the December solstice? A. Only at the equator B. Only at the North Pole C. Only at the South Pole. D. Only on the Antarctic Circle (latitude 66.5°S) E. Everywhere between the Arctic Circle (latitude 66.5°N) and the North Pole F. Everywhere between the Antarctic Circle (latitude 66.5°S) and the South Pole

F. Everywhere between the Antarctic Circle (latitude 66.5°S) and the South Pole

We see a ___ when the entire Moon is within Earth's full shadow A. Full shadow (umbra) B. Total solar eclipse C. penumbral lunar eclipse D. Partial solar eclipse E. Partial lunar eclipse F. Total lunar eclipse G. Partial shadow (prenumbra)

F. Total lunar eclipse

___ the larger, surrounding region of an object's shadow in which light from the Sun is only partially blocked A. Full shadow (umbra) B. Total solar eclipse C. penumbral lunar eclipse D. Partial solar eclipse E. Partial lunar eclipse F. Total lunar eclipse G. Partial shadow (prenumbra)

G. Partial shadow (prenumbra)

At most times, Mars appears to move ___ relative to the stars. The exceptions are during its periods of apparent retrograde motion, when Mars appears to move ___ relative to the stars. A. vertically B. northward C. horizontally D. southward E. fast F. westward G. eastward H. slow

G. eastward, F. westward