AST2002 -Final Study Guide and All
Correct/Verified Answers 2025-2026
Updated.
What is the celestial sphere and how do the stars and sun relate to it? - Answer an imaginary
hollow sphere where ancients believed the stars were hung and carried around the earth;
useful in modern astronomy to describe the location of celestial objects
What are the effects of the Earth's rotation, its revolution, and its tilt? - Answer Earth's
rotation is the cause for the differences in daytime and nighttime as it spins on its axis. When
that axis is tilted towards the sun, the Northern Hemisphere receives more radiation than the
Southern and vice versa when the axis is tilted away from the sun.
Explain the phases of the moon. - Answer New Moon, Waxing Crescent, First Quarter,
Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, Waning Crescent
Ptolemy contributions - Answer -Earth centered universe
-Retrograde Motion
Copernicus contributions - Answer -Heliocentric Model
-Proper order of Planets
-F*ck Geocentric Model
Brahe contributions - Answer -1st detailed observational data on planetary motion
-Assistant was Kepler
-Irregularities in Moon's orbit
Kepler contributions - Answer -laws of planetary motion
-heliocentric
-depth perception
Galileo contributions - Answer -Made first telescopes
-Father of modern astronomy and physics
-Laid down basis for Newton's Laws of Motion
Kepler's Laws of Planetary Motion - Answer 1) every planet's orbit is an ellipse with the Sun
at a focus
,2) a line joining the Sun and a planet sweeps out equal areas in equal times
3) the square of a planet's orbital period is proportional to the cube of the semi-major axis of its
orbit.
What are Newton's Laws and why are they so important? - Answer 1. INERTIA: in the
absence of force, objects move in straight lines at constant speed. Objects at rest remain at rest
2. F=ma: result of a force is a curved path with centripetal force equal to the gravitational force
3. ACTION=REACTION: the sun puts a force on a planet but planets put equal force on the sun
What is the Universal Law of Gravitation? - Answer any 2 objects attract each other with a
force ; Force increases with mass and decreases with distance
Three types of energy - Answer Kinetic, potential, chemical
kinetic energy - Answer energy of motion
Law of Conservation of Energy - Answer Energy cannot be created or destroyed; it may be
transformed from one form into another, but the total amount of energy never changes
How do telescopes help us in astronomy? - Answer Telescopes collect electromagnetic
radiation from the sky and focuses it for better observation. Scientists have placed telescopes in
space in order to avoid the interference of our atmosphere caused by air and light pollution.
Science - Answer A way of thinking, not a collection of facts; always open to modification.
scientific hypothesis - Answer An educated guess that attempts to explain a scientific law or
certain scientific observations;
astronomy - Answer The branch of science which deals with celestial objects, space, and the
physical universe as a whole.
meter - Answer SI base unit for length
, second - Answer SI base unit for time
kilogram - Answer SI base unit for mass
astronomical unit (AU) - Answer The average distance between the Earth and the Sun; 150
million km
light-year - Answer The distance light travels in one year; 9.5 trillion km
parsec - Answer Unit of measurement used to describe distances between celestial objects,
equal to 3.26 light years; 30 trillion km
parallax - Answer An apparent shift in the position of an object when viewed from different
locations; d=1/p
constellation - Answer A group of stars that form a pattern in the sky; 88 recognized by IAU
celestial sphere - Answer The imaginary sphere on which objects in the sky appear to reside
when observed from Earth
celestial pole - Answer The points in the sky directly overhead Earth's North and South poles
celestial equator - Answer Projection of Earth's equator into space; makes a complete circle
around the celestial sphere
ecliptic - Answer Path the sun follows as it appears to circle around the celestial sphere once
each year
zenith - Answer Point directly overhead; 90 degrees
horizon - Answer Boundary between earth and sky
declination - Answer A measure of how far north or south an object is from the celestial
equator
right ascension - Answer The angular distance eastward along the celestial equator from the
vernal equinox to the intersection of the hour circle that passes through the body
Correct/Verified Answers 2025-2026
Updated.
What is the celestial sphere and how do the stars and sun relate to it? - Answer an imaginary
hollow sphere where ancients believed the stars were hung and carried around the earth;
useful in modern astronomy to describe the location of celestial objects
What are the effects of the Earth's rotation, its revolution, and its tilt? - Answer Earth's
rotation is the cause for the differences in daytime and nighttime as it spins on its axis. When
that axis is tilted towards the sun, the Northern Hemisphere receives more radiation than the
Southern and vice versa when the axis is tilted away from the sun.
Explain the phases of the moon. - Answer New Moon, Waxing Crescent, First Quarter,
Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, Waning Crescent
Ptolemy contributions - Answer -Earth centered universe
-Retrograde Motion
Copernicus contributions - Answer -Heliocentric Model
-Proper order of Planets
-F*ck Geocentric Model
Brahe contributions - Answer -1st detailed observational data on planetary motion
-Assistant was Kepler
-Irregularities in Moon's orbit
Kepler contributions - Answer -laws of planetary motion
-heliocentric
-depth perception
Galileo contributions - Answer -Made first telescopes
-Father of modern astronomy and physics
-Laid down basis for Newton's Laws of Motion
Kepler's Laws of Planetary Motion - Answer 1) every planet's orbit is an ellipse with the Sun
at a focus
,2) a line joining the Sun and a planet sweeps out equal areas in equal times
3) the square of a planet's orbital period is proportional to the cube of the semi-major axis of its
orbit.
What are Newton's Laws and why are they so important? - Answer 1. INERTIA: in the
absence of force, objects move in straight lines at constant speed. Objects at rest remain at rest
2. F=ma: result of a force is a curved path with centripetal force equal to the gravitational force
3. ACTION=REACTION: the sun puts a force on a planet but planets put equal force on the sun
What is the Universal Law of Gravitation? - Answer any 2 objects attract each other with a
force ; Force increases with mass and decreases with distance
Three types of energy - Answer Kinetic, potential, chemical
kinetic energy - Answer energy of motion
Law of Conservation of Energy - Answer Energy cannot be created or destroyed; it may be
transformed from one form into another, but the total amount of energy never changes
How do telescopes help us in astronomy? - Answer Telescopes collect electromagnetic
radiation from the sky and focuses it for better observation. Scientists have placed telescopes in
space in order to avoid the interference of our atmosphere caused by air and light pollution.
Science - Answer A way of thinking, not a collection of facts; always open to modification.
scientific hypothesis - Answer An educated guess that attempts to explain a scientific law or
certain scientific observations;
astronomy - Answer The branch of science which deals with celestial objects, space, and the
physical universe as a whole.
meter - Answer SI base unit for length
, second - Answer SI base unit for time
kilogram - Answer SI base unit for mass
astronomical unit (AU) - Answer The average distance between the Earth and the Sun; 150
million km
light-year - Answer The distance light travels in one year; 9.5 trillion km
parsec - Answer Unit of measurement used to describe distances between celestial objects,
equal to 3.26 light years; 30 trillion km
parallax - Answer An apparent shift in the position of an object when viewed from different
locations; d=1/p
constellation - Answer A group of stars that form a pattern in the sky; 88 recognized by IAU
celestial sphere - Answer The imaginary sphere on which objects in the sky appear to reside
when observed from Earth
celestial pole - Answer The points in the sky directly overhead Earth's North and South poles
celestial equator - Answer Projection of Earth's equator into space; makes a complete circle
around the celestial sphere
ecliptic - Answer Path the sun follows as it appears to circle around the celestial sphere once
each year
zenith - Answer Point directly overhead; 90 degrees
horizon - Answer Boundary between earth and sky
declination - Answer A measure of how far north or south an object is from the celestial
equator
right ascension - Answer The angular distance eastward along the celestial equator from the
vernal equinox to the intersection of the hour circle that passes through the body
