Exam I Material Flashcards
An asteroid orbits the Sun at an average distance a = 4 AU. How long does it take to orbit the Sun?
a) 4 years
b) 8 years
c) 16 years
d) 64 years
b) 8 years
A result of Kepler’s “equal areas in equal times” law is _________.
a) a planet moves the same speed always
b) a planet moves slowest at aphelion
c) a planet moves fastest at aphelion
d) all planets move the same direction around the Sun
e) none of the above
b) a planet moves slowest at aphelion
Star A is 5 times farther from the Earth than star B. Which has larger stellar parallax?
a) star A
b) star B
c) the stellar parallax for each one is the same
d) not enough information is given
b) star B
An example of retrograde motion is when Jupiter moves _____ in the sky with respect to the stars; it occurs when Jupiter is _____ to the Earth.
a) west to east; closest
b) east to west; closest
c) west to east; farthest
d) east to west; farthest
b) east to west; closest
The sidereal day is one rotation of the Earth relative to the ____, while the solar day is one rotation of the Earth relative to the ____. The ____ day is longer by 4 minutes.
a) Sun; stars; solar
b) Sun; stars; sidereal
c) stars; Sun; solar
d) stars; Sun; sidereal
c) stars; Sun; solar
The angular distance of a place north or south of the equator (parallels).
latitude
The angular distance of a place east or west of the prime meridian (meridians).
longitude
A circle on the surface of a sphere that lies in a plane passing through the sphere’s center.
great circle
An imaginary great circle passing through the poles and the royal observatory in Greenwich England.
prime meridian
Positioned in or relating to the sky or outer space.
celestial
An imaginary sphere of which the observer is the center and on which all celestial objects are considered to lie.
celestial sphere
A recognizable pattern in the night sky.
constellation
A prominent pattern or group of stars typically having a popular name.
asterism
Of or with respect to the distant stars.
sidereal
Of or resulting from the daily rotation of the Earth.
diurnal
Astronomical latitude; measured north or south of the celestial equator.
declination
Astronomical longitude; measured in hours along the celestial equator.
right ascension
Inclined at an angle that is not a right angle or parallel.
oblique
LST
local sidereal time
The science of the origin and development of the universe.
cosmology
A star (or motion) above the horizon at all times in a given latitude.
circumpolar
A celestial body moving in an elliptical orbit around a star.
planet
Proceeding from west to east (of planetary motion).
prograde
A reverse direction from normal.
retrograde
The angle observed from the Earth between the direction of the Sun and the direction to a planet.
elongation
An elongation of 0 degrees (co-linear with the Earth and the Sun).
conjunction
An elongation of 180 degrees (co-linear with the Earth and the Sun).
opposition
An observed shift in a star’s apparent position resulting from the Earth’s motion around the Sun.
stellar parallax
The apparent motion of a star across the celestial sphere at right angles to the observer’s line of sight.
proper motion
Movement toward or away from the Sun.
radial motion
The point of greatest or least distance of a body from one of the foci of its elliptical orbit.
apsis
The point in the path of an orbiting body at which it is nearest to the body that it orbits.
periapsis
The point in the path of an orbiting body at which it is furthest from the body that it orbits.
apoapsis
A property of matter by which it continues in its existing state if rest or uniform motion in a straight line unless that state is changed by an external force.
intertia
Moving in a geosynchronous orbit in the plane of the equator so that it remains stationary in relation to a fixed point on the surface.
geostationary
By locating the north celestial pole (NCP) in the sky, how can you determine your latitude?
a) the altitude of the NCP is the same as your latitude
b) the altitude of the NCP is your angular distance from the North Pole
c) the azimuth of the NCP is the same as your latitude
d) the azimuth of the NCP is the angular distance from the North Pole
e) the altitude of the NCP is the same as your distance from the North Pole
a) the altitude of the NCP is the same as your latitude
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 “on top” of Earth and therefore receives more
sunlight
c) the Northern Hemisphere is tilted toward the Sun and receives more direct
sunlight
d) the Northern Hemisphere is tilted away from the Sun and receives more
indirect sunlight
e) it isn’t: both hemispheres have the same seasons at the same time
c) the Northern Hemisphere is tilted toward the Sun and receives more direct
sunlight
Which of the following statements about the celestial equator is true at all latitudes?
a) it lies along the band of light we call the Milky Way
b) it represents an extension of Earth’s equator onto the celestial sphere
c) it cuts the dome of your sky exactly in half
d) it extends from your horizon due east, through your zenith, to your horizon
due west
e) it extends from your horizon due north, through your zenith, to your horizon
due south
b) it represents an extension of Earth’s equator onto the celestial sphere
What is the hour angle of a star crossing your meridian?
a) -6 hours
b) 0 hours
c) 6 hours
d) it depends on your latitude
e) it depends on the right ascension of the star
b) 0 hours
Which of the following correctly describes the meridian in your sky?
a) a half-circle extending from your horizon due east, through your zenith, to
your horizon due west
b) a half-circle extending from your horizon due north, through your zenith, to
your horizon due south
c) a half-circle extending from your horizon due east, through the north celestial pole, to your horizon due west
d) the point directly over your head
e) the boundary between the portion of the celestial sphere you can see at any
moment and the portion that you cannot see
b) a half-circle extending from your horizon due north, through your zenith, to
your horizon due south
Which of the following best describes the modern definition of a constellation?
a) a region of the celestial sphere
b) a pattern of bright stars in the sky
c) a Greek mythological figure
d) a collection of stars that are near one another in space
e) a group of stars that all lie at about the same distance from Earth
a) a region of the celestial sphere
What is the ecliptic?
a) when the Moon passes in front of the Sun
b) the Moon’s apparent path along the celestial sphere
c) the constellations commonly used in astrology to predict the future
d) the Sun’s daily path across the sky
e) the Sun’s apparent path along the celestial sphere
e) the Sun’s apparent path along the celestial sphere
The fact the Orion is a constellation of our winter sky and is not visible on a summer
evening is due to:
a) the Earth’s rotation on its axis
b) the Earth’s revolution around the Sun
c) the Earth’s precession
d) Orion being at the north celestial pole
b) the Earth’s revolution around the Sun
Stars that never appear to set are called circumpolar. As you move from Earth’s
equator toward the North Pole, the number of stars that are circumpolar:
a) increases
b) decreases
c) stays the same
d) all stars are circumpolar
a) increases
Ptolemy introduced epicycles to explain _______________.
a) stellar motions
b) the seasons
c) the phases of the Moon
d) eclipses
e) retrograde motion of planets
e) retrograde motion of planets
Once a planet’s sidereal period is know, you can use Kepler’s 3rd law to determine
__________________.
a) the planet’s distance (semi major axis) from the Sun
b) the planet’s orbital speed
c) the planet’s rotational speed
d) the planet’s orbital direction
a) the planet’s distance (semi major axis) from the Sun
Which of the following planets never reaches opposition as seen from the Earth?
a) Venus
b) Mars
c) Jupiter
d) Neptune
e) they all reach opposition
a) Venus
The time between rising and setting of a star:
a) is always 12 hours
b) depends on the star’s declination
c) depends on the star’s right ascension
d) depends on the observer’s latitude
e) depends on the observer’s longitude
d) depends on the observer’s latitude
Suppose you live at latitude 40°N. Which of the following describes the path of the
celestial equator through your sky?
a) it goes from due south on your horizon, to your zenith, to due north on your
horizon
b) it goes from due east on your horizon, to your zenith, to due west on your
horizon
c) it goes from due east on your horizon, to an altitude of 50° in the south, to
due west on your horizon
d) it goes from due east on your horizon, to an altitude of 40° in the south, to
due west on your horizon
e) it goes from due east on your horizon, to an altitude of 40° in the north, to due
west on your horizon
c) it goes from due east on your horizon, to an altitude of 50° in the south, to
due west on your horizon
Suppose you live at latitude 40°N. Which of the following describes the conditions
that make a star circumpolar?
a) stars are circumpolar if they have declination > +50°
b) stars are circumpolar if they have declination > +40°
c) stars are circumpolar if they have right ascension > 6 hr
d) stars are circumpolar if they have right ascension < 6 hr
e) no stars are circumpolar at this latitude
a) stars are circumpolar if they have declination > +50°
Suppose the date is March 21 and the Sun passes through your zenith at noon.
Where are you?
a) the equator
b) the Tropic of Cancer
c) the Tropic of Capricorn
d) the Arctic Circle
e) the Antarctic Circle
a) the equator
The Sun is on your meridian, and you have a UT clock that tells you it is 3 P.M. in
Greenwich. What is your longitude?
a) 3° west of Greenwich
b) 3° east of Greenwich
c) 45° west of Greenwich
d) 45° east of Greenwich
e) 30° west of Greenwich
c) 45° west of Greenwich
Saturn is closest to the Earth at ______________.
a) conjunction
b) greatest elongation
c) quadrature
d) opposition
d) opposition
______ was the first to observe Jupiter’s moons, Saturn’s rings, phases of Venus,
and sunspots.
galileo
______ determined a scale size of the Solar System based on a heliocentric model,
and determined sidereal periods for all the planets (that were known in his/her time).
copernicus
______ was the first to make a reasonably accurate estimate of the Earth’s size.
erastosthenes
______ observe planetary positions with sufficient accuracy so that _______ could later use the data to discover the laws of planetary motion.
brahe; kepler
