ASTR 100 - Hmk 3
If we have a new moon today, when we will have the next full moon? (a) in about a month (b) in about 2 weeks (c) in about 1 week (d) in about 6 months
(b) in about 2 weeks
If the Sun rises precisely due east, (a) you must be located at Earth's equator. (b) it must be the day of either the spring or fall equinox. (c) it must be the day of the summer solstice.
(b) it must be the day of either the spring or fall equinox.
If you were standing on Earth's equator, where would you look to see the north celestial pole? (a) due east (b) on your horizon due north (c) toward the ecliptic directly overhead
(b) on your horizon due north
How many arc minutes are in a full circle?
21600 arcminutes
Why do we have seasons on Earth? (a) As Earth goes around the Sun and Earth's axis remains pointed toward Polaris, the Northern and Southern hemispheres alternately receive more and less direct sunlight. (b) The tilt of Earth's axis constantly changes between 0 and 23 1/2°, giving us summer when (c) Earth is tilted more and winter when it is straight up. (d) Earth's distance from the Sun varies, so that it is summer when we are closer to the Sun and winter when we are farther from the Sun. (e) Seasons are caused by the influence of the planet Jupiter on our orbit.
(a) As Earth goes around the Sun and Earth's axis remains pointed toward Polaris, the Northern and Southern hemispheres alternately receive more and less direct sunlight.
The Sun rises and sets each day because (a) Earth rotates once each day (b) it undergoes retrograde motion each day (c) its position seems to change because of stellar parallax (d) it orbits Earth once each day
(a) Earth rotates once each day (Earth rotates daily from west to east, which is why we see the Sun appear to rise in the east and set in the west.)
What is the basic reason that we have seasons on Earth? (a) Earth's axis is tilted relative to the ecliptic plane. (b) The amount of energy put out by the Sun varies over the course of each year. (c) Earth's orbit is not quite a perfect circle. (d) Earth's distance from the Sun varies over the course of each year.
(a) Earth's axis is tilted relative to the ecliptic plane. (As shown in the video, the tilt of Earth's axis means that sunlight hits the two hemispheres differently as we orbit the Sun, leading to opposite seasons in the Northern and Southern Hemispheres.)
What happens to Earth's axis as we orbit around the Sun over the course of each year? (a) It remains pointed in the same direction at all times. (b) It sweeps out a cone while remaining at a 23½° tilt, so that it sometimes points toward Polaris and sometimes toward other stars. (c) It wobbles back and forth, so that the tilt varies between 0° and 23½°.
(a) It remains pointed in the same direction at all times. (The axis remains pointed in the direction of Polaris at all times. That is why the orientation relative to the Sun changes over the course of the year.)
In spring, the axis points toward (a) Polaris. (b) Vega. (c) Sun.
(a) Polaris.
Which of the following statements are true about summer compared to winter? Select all that apply. (a) The Sun follows a longer and higher path through your sky in summer. (b) Temperatures tend to be warmer in summer. (c) At a given time of day, shadows are longer in summer. (d) You have more daylight and less darkness in summer.
(a) The Sun follows a longer and higher path through your sky in summer. (b) Temperatures tend to be warmer in summer. (d) You have more daylight and less darkness in summer. (The key features of summer are a longer and higher path for the Sun through the sky, which means more concentrated sunlight — generally leading to higher temperatures — and shorter shadows.)
What conditions are required for a solar eclipse? (a) 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. (b) The phase of the Moon must be full, and the Moon's orbital plane must lie in the ecliptic. (c) 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. (d) The phase of the Moon must be new, and the Moon's orbital plane must lie in the ecliptic. (e) The phase of the Moon can be new or full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun.
(a) 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 is the cause of the seasons? (a) The tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year. (b) Earth's speed varies in its orbit around the Sun, giving us summer when Earth is moving fastest and winter when Earth is moving slowest. (c) The tilt of Earth's axis causes the Northern Hemisphere to be closer to the Sun than the Southern Hemisphere in summer, and vice versa in winter. (d) The seasons are caused by variation in the amount of rainfall (or snowfall) in different places at different times of year.
(a) The tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year. (Without axis tilt, we would not have seasons on Earth. Seasons on other planets occur for the same reason, which is why planets with axis tilts (such as Mars and Saturn) have seasons and planets with very little axis tilt (such Jupiter or the "upside-down" axis of Venus) do not.)
Which statement best describes how variation in the Earth-Sun distance affects the seasons? (a) The variation in Earth-Sun distance over the course of each year has virtually no effect on the seasons. (b) No matter where you live or what the seasons, it is generally hotter when Earth is closer to the Sun and colder when Earth is farther from the Sun. (c) Summer occurs when Earth is closer to the Sun and winter occurs when Earth is farther from the Sun.
(a) The variation in Earth-Sun distance over the course of each year has virtually no effect on the seasons. (Seasons on Earth are not affected by the variation in Earth's orbital distance over the course of each year. This is probably not too surprising when you realize that Earth always stays within about 3 percent of its average distance from the Sun. Other factors are much more important in creating the seasons.)
A total solar eclipse can only happen during what lunar phase? (a) new (b) waning gibbous (c) full (d) first quarter
(a) new A solar eclipse occurs when the Moon's shadow falls on Earth, which can only happen when the Moon is between the Earth and Sun, which means during the new Moon.
When someone on Earth observes the Moon in the first-quarter phase, someone on the Moon facing Earth observes Earth in the (a) third-quarter Earth phase. (b) full Earth phase. (c) new Earth phase. (d) first-quarter Earth phase. (e) crescent Earth phase.
(a) third-quarter Earth phase.
What happens during the apparent retrograde motion of a planet? (a) The planet moves through constellations that are not part of the zodiac. (b) The planet appears to move westward with respect to the stars over a period of many nights. (c) The planet moves backward through the sky over the course of a night. (d) The planet rises in the west and sets in the east. (e) The planet moves backward in its orbit around the Sun.
(b) The planet appears to move westward with respect to the stars over a period of many nights.
Which of the following is not a phase of the Moon? (a) new Moon (b) half Moon (c) third-quarter Moon (d) full Moon (e) first-quarter Moon
(b) half Moon
Which of the following statements about phases of the Moon are true? Select all that apply. (a) at new moon, the Moon's entire surface is engulfed in darkness (b) the time between new moon and full moon is about two weeks (c) at new moon, we see only the "night" side of the Moon (d) at new moon, the half of the Moon facing the Sun is fully illuminated (e) if it's new moon, the Moon will rise in the middle of the day (f) if it is full moon, the Moon will rise around sunset (g) the time between first-quarter moon and third-quarter moon is about a month
(b) the time between new moon and full moon is about two weeks (c) at new moon, we see only the "night" side of the Moon (d) at new moon, the half of the Moon facing the Sun is fully illuminated (f) if it is full moon, the Moon will rise around sunset (Since the half of the Moon's surface that faces the Sun is always lit, the phase is determined by how much of it we see as it orbits the Earth.)
As seen from Earth, the Sun appears to follow the annual path that we call the __________ around the celestial sphere. (a) celestial equator (b) north celestial pole (c) ecliptic (d) constellations (e)milky way (f) south celestial pole
(c) ecliptic (Key markings on the celestial sphere include the north and south celestial poles, which are directly above Earth's north and south poles (respectively); the celestial equator, which is an extension of Earth's equator into space; and the ecliptic, which is the annual path of the Sun and which is tilted by 23 1/2° to the celestial equator because of the tilt of Earth's axis.)
If the Moon is setting at 6 A.M., the phase of the Moon must be (a) waning crescent. (b) new. (c) full. (d) third quarter. (e) first quarter.
(c) full.
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 June solstice only (b) on both the June and December solstices (c) on both the March and September equinoxes (d) on the December solstice only (e) on the March equinox only
(c) on both the March and September equinoxes (Recall that equinox means "equal night," so the two equinoxes are the dates on which all locations (except the poles) have equal amounts of daylight and darkness. Note: More technically, these are the dates on which the Sun is above the horizon for 12 hours and below it for 12 hours; of course, it does not instantly become dark when the Sun is below the horizon, so there is still some "daylight" in the evening and predawn hours.)
What is special about the June solstice? (a) It's the day when Earth has the greatest axis tilt. (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 on which the Northern Hemisphere receives its most direct sunlight.
(d) It's the day on which the Northern Hemisphere receives its most direct sunlight. (The June solstice is when the Northern Hemisphere is most directly oriented toward the Sun, which is why this hemisphere gets its most direct sunlight on this day.)
Why is it summer in the Northern Hemisphere when it is winter in the Southern Hemisphere? (a) The Northern Hemisphere is closer to the Sun than the Southern Hemisphere. (b) The Northern Hemisphere is tilted away from the Sun and receives more indirect sunlight. (c) The Northern Hemisphere is "on top" of Earth and therefore receives more sunlight. (d) The Northern Hemisphere is tilted toward the Sun and receives more direct sunlight. (e) It isn't: both hemispheres have the same seasons at the same time.
(d) The Northern Hemisphere is tilted toward the Sun and receives more direct sunlight.
Suppose you live on the Moon. How long is a day (i.e., from sunrise to sunrise)? (a) 24 hours (b) 23 hours 56 minutes (c) about 18 years (d) a lunar month (e) a year
(d) a lunar month
At approximately what time would a full Moon be on your meridian? (a) noon (b) 6 A.M. (c) 9 A.M. (d) midnight (e) 6 P.M.
(d) midnight
If the Moon is rising at midnight, the phase of the Moon must be (a) waning crescent. (b) waxing crescent. (c) full. (d) third quarter. (e) first quarter.
(d) third quarter.
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) galaxies (b) the Moon (c) stars (d) the Sun (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.
What causes the apparent retrograde motion of the planets? (a) Apparent retrograde motion is an illusion created by turbulence in Earth's atmosphere. (b) The other planets never really appear to move backward; the background stars shift due to Earth's revolution around the Sun. (c) As Earth passes another planet, its gravitational pull slows down the other planet so that it appears to be traveling backward. (d) When planets are farther from the Sun, they move slower than when they are nearer the Sun; it is during this slower period that they appear to move backwards. (e) 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 actually change.
(e) 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 actually change.
At approximately what time would a first quarter Moon rise? (a) midnight (b) 6 A.M. (c) 9 A.M. (d) 6 P.M. (e) noon
(e) noon
Orion is visible on winter evenings in the northern hemisphere but not summer evenings because of (a) the tilt of Earth's axis. (b) baseball on television. (c) interference from the full Moon. (d) the precession of Earth's axis. (e) the location of Earth in its orbit.
(e) the location of Earth in its orbit.
Rank each of the six lunar positions based on the amount of the Moon's illuminated surface that is visible from Earth, from greatest to least.
Because exactly half the Moon's surface is illuminated at all times, the phases occur only because, from Earth, we see different amounts of the Moon's illuminated and non-illuminated faces. In other words, contrary to a common misconception, phases are NOT caused by shadows from Earth; the only time that Earth's shadow ever falls on the Moon is during a lunar eclipse (and the instructions told you to assume that is not the case in these diagrams).
The following figures show a top view of Earth, sunlight, and six different positions of the Moon as it orbits Earth. Note that the distances shown are not drawn to scale. Rank each of the six lunar positions from left to right based on the amount of the Moon's illuminated surface that is visible from Earth, from greatest to least. (If two diagrams have an equal amount of illumination as seen from Earth, put one on top of the other.)
Because exactly half the Moon's surface is illuminated at all times, the phases occur only because, from Earth, we see different amounts of the Moon's illuminated and non-illuminated faces. In other words, contrary to a common misconception, phases are NOT caused by shadows from Earth; the only time that Earth's shadow ever falls on the Moon is during a lunar eclipse (and the instructions told you to assume that is not the case in these diagrams).
Rank the seasons for the Southern Hemisphere based on Earth's distance from the Sun when each season begins, from closest to farthest: 1) fall 2) spring 3) winter 4) summer
Closest to farthest from the Sun: 1) summer 2) fall 3) spring 4) winter (The fact that the two hemispheres have opposite seasons is further proof that the seasons are not caused by Earth's varying distance from the Sun. Keep in mind that Earth is so small in size (diameter 12,800 km) compared to its distance from the Sun (about 150 million km) that there is no significant difference in the distances of the two hemispheres from the Sun; therefore, if the seasons were caused by Earth's varying distance from the Sun, the entire Earth would have summer at the same time.)
Rank the seasons for the Northern Hemisphere based on Earth's distance from the Sun when each season begins, from closest to farthest: 1) fall 2) spring 3) winter 4) summer
Closest to farthest from the Sun: winter, spring, fall, summer Many people guess that seasons are caused by variations in Earth's distance from the Sun, but if that were the case, we'd expect it to be warmest (summer) when Earth is closest to the Sun. As you can see in the rankings, Earth is actually farthest from the Sun when it is summer in the Northern Hemisphere. We conclude that variations in the Earth-Sun distance from are not the major cause of our seasons.)
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.
Rank each of the six lunar positions based on the amount of the Moon's total surface that is illuminated by sunlight.
Exactly half of the Moon's surface is illuminated by sunlight at all times. However, the amount of the illuminated face that we see from Earth varies with the Moon's orbital position.
The following figures show a top view of Earth, sunlight, and six different positions of the Moon as it orbits Earth. Note that the distances shown are not drawn to scale. Rank each of the six lunar positions based on the amount of the Moon's total surface that is illuminated by sunlight. If two (or more) diagrams have an equal amount of surface illuminated by sunlight, put one on top of the other. (Assume that conditions for an eclipse are not met in any of these diagrams.)
Exactly half of the Moon's surface is illuminated by sunlight at all times. However, the amount of the illuminated face that we see from Earth varies with the Moon's orbital position.
(True/False) A lunar eclipse occurs only when the Moon is new.
False
(True/False) It is possible to see the full Moon rising just before sunrise.
False
Waxing Gibbous: Rank the phases from left to right based on the order in which you would see them over the subsequent four weeks, from first seen to last.
Remember that "waxing" phases mean on the way to full moon and "waning" phases mean after full moon. So if tonight is a waxing gibbous moon, then we are headed toward full moon in about three to four days. Because the full moon is not shown, we'd next see a waning gibbous moon, then a third-quarter moon, and then a waning crescent. From there we'd have new moon (which isn't shown), then the waxing crescent, and then first-quarter. Finally, a about a "moonth" from now (29 1/2 days), we'd once again have a waxing gibbous moon.
(True/False) A year at the south pole consists of 6 months of darkness and 6 months of daylight.
True
