Download The most important questions to study for the exam

Comins DEU 3e Ch 01 Quiz 1 completed
The correct answers are written in bold, italic and underlined.
The most important questions to study for the exam are highlighted.
1. We know that stars in our local region of the universe are moving
relative to one another. Why then, do we not see the patterns made up by
them, the constellations, changing night by night?
• The stars in each constellation are part of a "moving group," all moving the same direction, so their position
relative to each other does not change.
• The stars in the sky are at very large distances from us, and their nightly motions relative to one another are
not easily detected.
• The stars we see are all moving directly away from us; from our viewpoint, they do not appear to be moving.
2. Stars on the celestial equator appear to move through a full 360
degrees in about 1 day due to the Earth's rotation. How fast are they
moving, in degrees per minute?
• 15° per minute
• 4° per minute
• 1/4° per minute
3. Suppose that on a particular day the star Regulus in the
constellation Leo rises at exactly 11:30 p.m. At what time will it rise
2 days later?
• 11:22 p.m.
• 11:30 p.m.
• 11:38 p.m.
4. Over what fraction of the sky will the stars be circumpolar if you
are standing on the North Pole of the Earth?
• The whole visible sky, or one-half of the complete celestial sphere
• The region of the sky above an elevation of 66.5E
• The region of the sky above 23.5E of the horizon
5. Leap years, which contain 1 extra day, are needed in order to correct
for the fact that
• the Earth speeds up and slows down periodically in its orbit around the Sun.
• the length of the day has changed since the calendar was devised by ancient Greeks because of the effect of the
tides in slowing down the spin of the Earth.
•
1 year is not exactly 365 days, but about 365.25 days.
6. The main reason for the seasonal effects at mid-latitudes on the
Earth is
• the tilt of the spin axis of the Earth to its orbital plane, resulting in a change in the angle of incidence of
solar radiation on the Earth's surface as the it orbits around the Sun.
• the variation in the distance between the Sun and the Earth because of the elliptical orbit of the Earth, causing a
variation in the intensity of solar radiation on the Earth.
• the change in the tilt angle of the Earth's spin axis relative to the celestial equator. The Sun appears to move
along the equator in our sky, producing a change in the angle of solar radiation on the Earth.
7. The declination of the Sun on the first day of summer is
0E, by definition.
• +23.5E, north declination.
• variable because the Sun appears to move across the sky from our point of view as the Earth orbits the Sun.
8. The plane of the Earth's orbit around the Sun, the ecliptic plane,
over periods of hundreds of years,
• remains fixed at an angle of 23.5E to the celestial equator.
• is coincident with the celestial equator, by definition.
• varies between angles of +23.5E and -23.5E from the celestial equator through the year, making an angle of 0E
to the equator at midsummer and midwinter.
9. If the Sun's declination is +23.5E on June 21 of a particular year,
when will it next be this declination?
• 26,000 years later
• 6 months later
• 1 year later
10. At what part of its cycle will the Moon be seen high in the sky at
midnight, from mid-latitudes?
• Quarter Moon
• Just after new Moon
• Full Moon
11. The Moon shows different phases because
• the Moon moves slowly in and out of the Earth's shadow in its orbital motion around the Earth.
• the Moon rotates slowly to reveal more or less of its illuminated hemisphere while remaining relatively fixed
against the celestial sphere of stars.
•
we view the sunlit hemisphere of the Moon from different angles as the Moon orbits the Earth.
12. On a particular night, the Moon appears more than half full, and on
the following night it appears to be at quarter Moon. What was the phase
of the Moon on the first night?
• Waning gibbous
• Waning crescent
• Waxing gibbous
13. When does the first quarter Moon rise, approximately?
• At midnight
• At sunset
• At midday
14. Where will the full Moon be at sunrise in the northern hemisphere?
• Low in the western sky
• High in the southern sky
• Low in the eastern sky
15. How long will a lunar day be at a location on the Moon's equator?
• Infinite. The Sun will not appear to move in the sky, or rise and set, because the Moon does not rotate.
• About 29.5 days because the Moon rotates once per orbit around the Earth
• 1 year because the Moon rotates to keep one face toward the Sun as seen by the changing lunar phases
16. Astronauts have a great view of the Earth as they land at a lunar
base near the equator. How often will they see the Earth move over their
lunar horizon during their stay on the Moon?
• The Earth will move across their sky with a period of about 1 month, the rotation period of the Moon.
• The Earth will remain stationary in their sky and therefore will never cross their horizon.
• The Earth will move slowly across their sky, completing an orbit in 1 year.
17. Astronauts at a lunar base near the crater Copernicus note that the
Sun is high in their sky on March 1, 2020. When will it next reach this
high position in their sky?
• March 29, 2020, or 29.5 days after March 1
• March 27, 2020, or 27.3 days after March 1
• The Sun will remain fixed at this position in the lunar sky because the Moon does not rotate with respect to the
Sun.
18. During a total lunar eclipse, the Moon often appears deep red. Why
does this happen?
• The reddish tint is light from cities on the Earth's nightside reflecting from the darkened Moon.
•
•
Sunlight is bent into the Earth's shadow by the Earth's atmosphere.
The eclipse reduces the intensity of sunlight reflected from the Moon and this allows us to see the Moon's
natural color.
19. The reason eclipses do not occur at every new Moon and every full
Moon is that
• the Moon's orbit is inclined at an angle to the Earth's equator.
• the Moon's orbit is inclined at an angle to the Earth's orbit.
• the Earth's equator is inclined at an angle to the Earth's orbit.
20. Lunar eclipses occur
• about twice per year, when a specific part of the Earth is within the shadow of the Moon.
• about twice per year, when the Moon goes into the shadow of the Earth.
• every month, when the Moon moves into the Earth's shadow to produce the dark New Moon.
21. The typical size of the shadow of the Moon when it is cast on the
Earth during a total solar eclipse, from inside of which no part of the
solar disk is visible, is
• very large, extending over the whole sunlit Earth, such that everyone on this side of Earth sees an eclipse.
• about as large as the Moon, with a diameter of about 3500 km.
• very small, with a typical diameter less than about 270 km.
22. Why are some solar eclipses annular (with all but an annular ring of
the Sun obscured) rather than total (the whole Sun obscured)?
• The Moon's orbit is elliptical, and occasionally the Moon is too far away for the umbra of its shadow to
reach the Earth's surface.
• The Moon's shadow passes just north or south of the Earth, causing only an annular ring eclipse.
• The Earth is sometimes farther away from the Sun such that the Moon's angular diameter is less than that of the
Sun at this time.