The Essential Cosmic Perspective FINAL Exam Questions with Detailed Answers Already Passed
ecliptic - Answers the path the Sun follows as it appears to circle around the celestial sphere once each
year. It crosses the celestial equator at a 23 1/2° angle, because that is the tilt of Earth's axis.
triangulation - Answers a geometric method of measuring of the distance of a planet or nearby star by
sighting its apparent position against background stars from two or more separate locations.
celestial sphere - Answers the illusion that the stars and constellations lie on the same plane, a sphere
around the earth- and are the same distance away; ancient Greeks mistook this illusion for reality
because they lacked the depth perception, since the stars were so far away; a useful illusion, because it
allows us to map the sky as seen from Earth.
solstices - Answers The summer solstice, occurring around June 21, is the moment when the Northern
Hemisphere is tilted most directly toward the Sun (23° above the celestial equator) and the Southern
Hemisphere is tipped most directly away from it. The winter solstice, occurring around December 21, is
the moment when the Northern Hemisphere is tilted most directly away from the Sun (23° below the
celestial equator) and the Southern Hemisphere is tipped most directly toward it. The spring and fall
equinoxes (March & September) are the two times when both hemispheres get equally direct sunlight.
celestial coordinates - Answers a useful coordinate system for locating objects on the celestial sphere by
projecting onto the sky the latitude-longitude coordinate system that we use on the surface of the
earth; the coordinates of right ascension and declination that fix an object's position on the celestial
sphere.
locating an object in our local sky - Answers the boundary between Earth and sky defines the horizon.
The point directly overhead is the zenith. The meridian is an imaginary half- circle stretching from the
horizon due south, through the zenith, to the horizon due north; it divides rising stars from setting stars)
We can pinpoint the position of any object in the local sky by stating its direction along the horizon
(sometimes stated as azimuth, which is degrees clockwise from due north) and its altitude above the
horizon. Note that the zenith has altitude 90° but no direction, because it is straight overhead (i.e.: if the
north celestial pole is 35° above your northern horizon. This tells you that your latitude on the globe is
35° north of the equator).
How could you determine that the Earth is revolving around the sun? - Answers Parallax. Over the
course of one year many of the stars will move relative to each other. At the end of the year they will be
back where they started. This is because the Earth moves around in a 2AU diameter circle, so that six
months from your first observation, you'll be standing 2AU away from where you were then, and are
viewing the stars from a (slightly, but observably) different angle.
Polaris, the North Star, does not appear to move in the sky because - Answers it lies approximately over
the northern axis of the Earth.
How many arc seconds are in a degree? - Answers 3,600 seconds.
, What contribution to astronomy did Tycho Brahe make? - Answers He made extensive and detailed
observations of the positions of the planets.
The moon is growing more full each night. This is called - Answers waxing.
The Ptolemaic picture of the universe probably survived for so long because - Answers it was based on
precise measurements of planetary positions.
When we see Saturn going through a period of apparent retrograde motion, it means - Answers Earth is
passing Saturn in its orbit, with both planets on the same side of the Sun.
The age of our solar system is about - Answers One-third the age of our Universe.
I live in the United States, and during my first trip to Argentina
I saw many constellations that I'd never seen before. - Answers Yes, Argentina's southern location
affords us a different view of the night sky from what is visible in the United States.
astronomical unit - Answers or AU, equivalent to about 150 million kilometers (93 million miles); the
distance from the Earth to the Sun.
solar eclipse - Answers occurs when the moon passes directly between the sun and Earth and casts a
shadow over part of Earth.
aphelion - Answers the place in the orbit of a planet where it is farthest from the sun; the closest being
the perihelion.
autumnal equinox - Answers Occurs on or about September 22 when both hemispheres of the Earth
receive 12 hours of daylight and 12 hours of night.
retrograde motion - Answers The apparent motion of the planets when they appear to move backwards
(westward) with respect to the stars from the direction that they move ordinarily.
What is the zodiac, and why do we see different parts of it at different times of the year? - Answers the
12 constellations we see in our local sky; the Earth is tilted 23 ½° on it axis as we rotate around the sun,
west to east, making the stars appear to rise in the east and set in the west. We see different parts of
the zodiac depending on where Earth is in its orbit.
What is the Copernican revolution? - Answers The combined research, observational data and theories
of Copernicus, Tycho Brahe, and Kepler, finalized by Galileo. Copernicus overturned the Ptolemaic
model (theory that each planet moves on a small circle whose center moves around Earth on a larger
circle) in favor of a sun-centered model. Brahe continued this work and improved it (only slightly), using
years of naked-eye observation. He hired Kepler, who discovered through discrepancies in Brahe's data
on planetary motion (Brahe could not detect stellar parallax & thought planets orbited in perfect circles)
that orbits are ellipses. This helped him postulate his 3 laws of planetary motion. Galileo then cemented
the sun-centered model with discoveries and observation with his telescope (moons of Jupiter, etc.) and
refuted all objections.
ecliptic - Answers the path the Sun follows as it appears to circle around the celestial sphere once each
year. It crosses the celestial equator at a 23 1/2° angle, because that is the tilt of Earth's axis.
triangulation - Answers a geometric method of measuring of the distance of a planet or nearby star by
sighting its apparent position against background stars from two or more separate locations.
celestial sphere - Answers the illusion that the stars and constellations lie on the same plane, a sphere
around the earth- and are the same distance away; ancient Greeks mistook this illusion for reality
because they lacked the depth perception, since the stars were so far away; a useful illusion, because it
allows us to map the sky as seen from Earth.
solstices - Answers The summer solstice, occurring around June 21, is the moment when the Northern
Hemisphere is tilted most directly toward the Sun (23° above the celestial equator) and the Southern
Hemisphere is tipped most directly away from it. The winter solstice, occurring around December 21, is
the moment when the Northern Hemisphere is tilted most directly away from the Sun (23° below the
celestial equator) and the Southern Hemisphere is tipped most directly toward it. The spring and fall
equinoxes (March & September) are the two times when both hemispheres get equally direct sunlight.
celestial coordinates - Answers a useful coordinate system for locating objects on the celestial sphere by
projecting onto the sky the latitude-longitude coordinate system that we use on the surface of the
earth; the coordinates of right ascension and declination that fix an object's position on the celestial
sphere.
locating an object in our local sky - Answers the boundary between Earth and sky defines the horizon.
The point directly overhead is the zenith. The meridian is an imaginary half- circle stretching from the
horizon due south, through the zenith, to the horizon due north; it divides rising stars from setting stars)
We can pinpoint the position of any object in the local sky by stating its direction along the horizon
(sometimes stated as azimuth, which is degrees clockwise from due north) and its altitude above the
horizon. Note that the zenith has altitude 90° but no direction, because it is straight overhead (i.e.: if the
north celestial pole is 35° above your northern horizon. This tells you that your latitude on the globe is
35° north of the equator).
How could you determine that the Earth is revolving around the sun? - Answers Parallax. Over the
course of one year many of the stars will move relative to each other. At the end of the year they will be
back where they started. This is because the Earth moves around in a 2AU diameter circle, so that six
months from your first observation, you'll be standing 2AU away from where you were then, and are
viewing the stars from a (slightly, but observably) different angle.
Polaris, the North Star, does not appear to move in the sky because - Answers it lies approximately over
the northern axis of the Earth.
How many arc seconds are in a degree? - Answers 3,600 seconds.
, What contribution to astronomy did Tycho Brahe make? - Answers He made extensive and detailed
observations of the positions of the planets.
The moon is growing more full each night. This is called - Answers waxing.
The Ptolemaic picture of the universe probably survived for so long because - Answers it was based on
precise measurements of planetary positions.
When we see Saturn going through a period of apparent retrograde motion, it means - Answers Earth is
passing Saturn in its orbit, with both planets on the same side of the Sun.
The age of our solar system is about - Answers One-third the age of our Universe.
I live in the United States, and during my first trip to Argentina
I saw many constellations that I'd never seen before. - Answers Yes, Argentina's southern location
affords us a different view of the night sky from what is visible in the United States.
astronomical unit - Answers or AU, equivalent to about 150 million kilometers (93 million miles); the
distance from the Earth to the Sun.
solar eclipse - Answers occurs when the moon passes directly between the sun and Earth and casts a
shadow over part of Earth.
aphelion - Answers the place in the orbit of a planet where it is farthest from the sun; the closest being
the perihelion.
autumnal equinox - Answers Occurs on or about September 22 when both hemispheres of the Earth
receive 12 hours of daylight and 12 hours of night.
retrograde motion - Answers The apparent motion of the planets when they appear to move backwards
(westward) with respect to the stars from the direction that they move ordinarily.
What is the zodiac, and why do we see different parts of it at different times of the year? - Answers the
12 constellations we see in our local sky; the Earth is tilted 23 ½° on it axis as we rotate around the sun,
west to east, making the stars appear to rise in the east and set in the west. We see different parts of
the zodiac depending on where Earth is in its orbit.
What is the Copernican revolution? - Answers The combined research, observational data and theories
of Copernicus, Tycho Brahe, and Kepler, finalized by Galileo. Copernicus overturned the Ptolemaic
model (theory that each planet moves on a small circle whose center moves around Earth on a larger
circle) in favor of a sun-centered model. Brahe continued this work and improved it (only slightly), using
years of naked-eye observation. He hired Kepler, who discovered through discrepancies in Brahe's data
on planetary motion (Brahe could not detect stellar parallax & thought planets orbited in perfect circles)
that orbits are ellipses. This helped him postulate his 3 laws of planetary motion. Galileo then cemented
the sun-centered model with discoveries and observation with his telescope (moons of Jupiter, etc.) and
refuted all objections.
