Download Quiz # 1

Introduction to Descriptive Astronomy
Summer 2012
Quiz # 1
Name: __________________________
1. The lowest amount of solar energy per square meter is incident on the surface of Earth in the northern
hemisphere on or about
A) September 21, the beginning of fall or autumn.
B) January 5, midwinter.
C) March 21, the end of winter.
D) December 21, the beginning of winter.
2. In the ancient Greek era, it was almost universally believed that the
A) Sun was at the center of the universe.
B) pole star represented the center of the universe about which the Earth and all other objects revolved.
C) Earth was at the center of the universe.
D) Milky Way represented the observable universe, and its center was the center of the universe.
3. The nightly motion of objects across our sky from horizon to horizon is caused by the
A) rotation of the whole celestial sphere of stars around the fixed Earth.
B) rotation of the Earth on its axis.
C) revolution of the Earth around the Sun.
D) motion of the solar system around the Galaxy.
4. Eclipses of the Moon can occur only
A) at new Moon.
B) at full Moon.
C) in the spring and fall, when the Sun is on the ecliptic plane.
D) in June and December, when the Sun is near the solstices.
5. The motions of the planets against the background stars in our sky can best be described as
A) regular and uniform eastward motion.
B) regular patterns with general westward motion interrupted by periods of eastward motion.
C) regular patterns with general eastward motion interrupted by periods of westward motion.
D) general eastward motion but with occasional stationary periods with no motion at all.
6. The Earth would not have seasons if
A) the observer's vertical axis (zenith) were perpendicular to the Earth's orbital plane.
B) its equatorial plane were perpendicular to its orbital plane.
C) its axis of rotation were perpendicular to its orbital plane.
D) its axis of rotation were perpendicular to its equatorial plane.
7. Two celestial coordinates that together describe a star's position precisely in our sky are
A) right ascension and sidereal time.
B) longitude and latitude.
C) sidereal time and latitude.
D) right ascension and declination.
8. Where would you have to be in either the northern or southern hemisphere for the Sun to remain below
the horizon for a 24-hour period for at least part of a year?
A) above about 23.5° latitude
B) only at 90°, or exactly at the poles
C) above about 66.5° latitude
D) nowhere because the Sun is always visible at some time of the day everywhere on Earth
9. When the Moon is in its gibbous phase, the positions of the Moon, the Earth, and the Sun are such that the
A) relative distances of the Earth and the Moon from the Sun are irrelevant because this phase can
occur at any time.
B) Moon is farther from the Sun than the Earth is.
C) Moon is closer to the Sun than the Earth is.
D) Earth and the Moon are at almost the same distance from the Sun.
10. The reason leap years have an extra day is to account for the fact that the
A) day is not exactly 24 hours because of the Earth's periodically varying rotation period.
B) Earth's rotation period is slowly increasing because of tidal effects.
C) length of the year varies with a period of four years because of precession.
D) year is not exactly equal to an integral number of days.
11. The Copernican system for planetary motions is
A) Earth-centered, with the planets moving in epicycles around the Earth.
B) Sun-centered, with the planets moving in perfect circles around the Sun.
C) Earth-centered, with the planets, the Sun, and the stars mounted on crystal spheres, pivoted to allow
the correct motions around the Earth.
D) Sun-centered, with the planets moving in elliptical orbits and the Sun at one focus of the ellipse.
12. The diameter of the hydrogen atom, 0.000,000,000,11 m, can be written in shorthand notation as
A) 1.1 × 10–11 m.
B) 1.1 × 10–8 m.
C) 1.1 × 10–10 m.
D) 1.1 × 10–9 m.
13. The plane of the ecliptic intersects the celestial equator
A) along the Prime Meridian.
B) at two points, the vernal and autumnal equinoxes.
C) everywhere because these are two different names for the same plane.
D) at two points, the summer and winter solstices.
14. Ptolemy's model for the solar system was
A) Sun-centered, with the planets moving in circles around it.
B) Earth-centered, with planetary orbits composed of deferents and epicycles.
C) Sun-centered, with elliptical planetary orbits.
D) Earth-centered, with the Sun, the Moon, and the planets moving in ellipses in the sky.
15. A solar day is the time it takes Earth to rotate on its axis between two consecutive solar positions (for
example, high noon to high noon or sunset to sunset). A sidereal day is the time it takes Earth to rotate
on its axis between two consecutive positions of a distant star (Vega on the eastern horizon to Vega again
on the eastern horizon). Which is longer?
A) A sidereal day is always longer.
B) A solar day and a sidereal day are always the same length.
C) A sidereal day is longer when Earth is farther from the Sun (northern summer), but a solar day is
longer when Earth is closer to the Sun (northern winter).
D) A solar day is always longer.
16. A vital part of the scientific hypothesis is that
A) it must be mathematically complex.
B) it must be mathematically simple.
C) it is possible, in principle, to disprove it by observation.
D) it is possible, in principle, to disprove it by logical argument.
17. If a modern astronomer describes a faint star as being in the constellation Cygnus, the Swan, you know
that the star is
A) inside our solar system.
B) in a distant galaxy located in a particular direction from the Earth.
C) one of a set of stars that make up a particular “picture,” in this case a swan, in the sky.
D) somewhere within a particular region of sky having definite boundaries.
18. Which of the following directions remains fixed in the sky relative to an observer's horizon?
A) zenith
B) direction toward the Moon at noon, over one month
C) autumnal equinox
D) direction toward the Sun at noon, over one year
19. The ecliptic can be defined as the
A) path traced out by the Sun in our sky over one year against the background stars.
B) path traced out by the Moon in our sky in one month against the background stars.
C) extension of the Earth's equator onto the sky.
D) plane that is perpendicular to the Earth's spin axis.
20. If the Moon in its orbit around the Earth moves alternately between the Earth and the Sun and behind the
Earth from the Sun, why do we not see solar and lunar eclipses every month?
A) The Moon's orbital plane is at right angles to the ecliptic.
B) The Moon's orbital plane is inclined slightly to the celestial equator, which is the path of the Sun
across the sky.
C) The Moon's orbital plane is slightly inclined to the ecliptic.
D) The Moon's motion in its orbit is so slow that it reaches eclipse position only once every six
months.
I pledge that I have acted honorably.
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