Where does "Described as central bulge; dusty cloud around the bulge." go?
1. Elliptical
2. Irregular
45 answers
1. Elliptical
Which galaxy and location can Earth's solar system be found?(1 point)
Responses
at the edge of the irregular Andromeda
at the edge of the irregular Andromeda
near the central bulge of the elliptical Milky Way
near the central bulge of the elliptical Milky Way
at the tip of one of Andromeda's spiral arms
at the tip of one of Andromeda's spiral arms
in the middle of one of the Milky Way's spiral arms
Responses
at the edge of the irregular Andromeda
at the edge of the irregular Andromeda
near the central bulge of the elliptical Milky Way
near the central bulge of the elliptical Milky Way
at the tip of one of Andromeda's spiral arms
at the tip of one of Andromeda's spiral arms
in the middle of one of the Milky Way's spiral arms
in the middle of one of the Milky Way's spiral arms
Asteroids can vary in size. They can be as small as ___________ and as large as ___________? (1 point)
Responses
Earth and as large as Saturn.
Earth and as large as Saturn.
A baseball and as large as the Moon.
A baseball and as large as the Moon.
Dust and as large as the state of Georgia.
Dust and as large as the state of Georgia.
The state of Florida and as large as North America.
Responses
Earth and as large as Saturn.
Earth and as large as Saturn.
A baseball and as large as the Moon.
A baseball and as large as the Moon.
Dust and as large as the state of Georgia.
Dust and as large as the state of Georgia.
The state of Florida and as large as North America.
A baseball and as large as the Moon.
Asteroids can vary in size. They can be as small as ___________ and as large as ___________? (1 point)
Responses
Earth and as large as Saturn.
Earth and as large as Saturn.
A baseball and as large as the Moon.
A baseball and as large as the Moon.
Dust and as large as the state of Georgia.
Dust and as large as the state of Georgia.
The state of Florida and as large as North America.
Select all that apply.
Responses
Earth and as large as Saturn.
Earth and as large as Saturn.
A baseball and as large as the Moon.
A baseball and as large as the Moon.
Dust and as large as the state of Georgia.
Dust and as large as the state of Georgia.
The state of Florida and as large as North America.
Select all that apply.
A baseball and as large as the Moon.
What is the correct term for a meteoroid if it enters the Earth's atmosphere? (1 point)
Responses
A star
A star
A comet
A comet
A meteor
A meteor
A moon
Responses
A star
A star
A comet
A comet
A meteor
A meteor
A moon
A meteor
Sam was gazing through a telescope and noticed a bright spot moving fast through the sky. On closer examination, he observed the spot was followed by a stream of dust. What did Same most likely observe?(1 point)
Responses
An asteroid
An asteroid
A comet
A comet
A meteor
A meteor
a moon
Responses
An asteroid
An asteroid
A comet
A comet
A meteor
A meteor
a moon
A comet
Which one of the following BEST describes another name for meteors?(1 point)
Responses
comets
comets
shooting stars
shooting stars
meteorites
meteorites
space fireballs
Responses
comets
comets
shooting stars
shooting stars
meteorites
meteorites
space fireballs
shooting stars
Scientist 1 determines that the object is a comet while scientist 2 determines that the object is an asteroid. Which scientist is correct and why?
(1 point)
Responses
Scientist 1 is correct. Because comets are made of dust and ice, comets are more likely to be found in the Oort cloud than asteroids, and only asteroids, not comets, develop tails as they approach the Sun.
Scientist 1 is correct. Because comets are made of dust and ice, comets are more likely to be found in the Oort cloud than asteroids, and only asteroids, not comets, develop tails as they approach the Sun.
Scientist 2 is correct. Because asteroids are made of dust and ice, asteroids are more likely to be found in the Oort cloud than comets, and an asteroid would not develop a visible tail that far away from the Sun.
Scientist 2 is correct. Because asteroids are made of dust and ice, asteroids are more likely to be found in the Oort cloud than comets, and an asteroid would not develop a visible tail that far away from the Sun.
Scientist 1 is correct. Because comets are made of dust and ice, comets are more likely to be found in the Oort cloud than asteroids, and a comet would not develop a visible tail that far away from the Sun.
Scientist 1 is correct. Because comets are made of dust and ice, comets are more likely to be found in the Oort cloud than asteroids, and a comet would not develop a visible tail that far away from the Sun.
Scientist 2 is correct. Because asteroids are made of dust and ice, asteroids are more likely to be found in the Oort cloud than comets, and only comets, not asteroids, develop tails as they approach the Sun.
(1 point)
Responses
Scientist 1 is correct. Because comets are made of dust and ice, comets are more likely to be found in the Oort cloud than asteroids, and only asteroids, not comets, develop tails as they approach the Sun.
Scientist 1 is correct. Because comets are made of dust and ice, comets are more likely to be found in the Oort cloud than asteroids, and only asteroids, not comets, develop tails as they approach the Sun.
Scientist 2 is correct. Because asteroids are made of dust and ice, asteroids are more likely to be found in the Oort cloud than comets, and an asteroid would not develop a visible tail that far away from the Sun.
Scientist 2 is correct. Because asteroids are made of dust and ice, asteroids are more likely to be found in the Oort cloud than comets, and an asteroid would not develop a visible tail that far away from the Sun.
Scientist 1 is correct. Because comets are made of dust and ice, comets are more likely to be found in the Oort cloud than asteroids, and a comet would not develop a visible tail that far away from the Sun.
Scientist 1 is correct. Because comets are made of dust and ice, comets are more likely to be found in the Oort cloud than asteroids, and a comet would not develop a visible tail that far away from the Sun.
Scientist 2 is correct. Because asteroids are made of dust and ice, asteroids are more likely to be found in the Oort cloud than comets, and only comets, not asteroids, develop tails as they approach the Sun.
Scientist 1 is correct. Because comets are made of dust and ice, comets are more likely to be found in the Oort cloud than asteroids, and only comets, not asteroids, develop tails as they approach the Sun.
Which word describes how the planets are held in Earth's solar system together?(1 point)
Responses
an atomic force
an atomic force
gravity
gravity
a tidal force
a tidal force
friction
friction
Question 10
Which of the following statements best describes the Moon's gravitational pull?(1 point)
Responses
The gravitational pull on the side Earth faces is stronger.
The gravitational pull on the side Earth faces is stronger.
The gravitational pull on the side Earth faces is weaker.
The gravitational pull on the side Earth faces is weaker.
The strength of the gravitational pull depends on the season.
The strength of the gravitational pull depends on the season.
The strength of the gravitational pull depends on the time of day.
The strength of the gravitational pull depends on the time of day.
Question 11
The forces of gravity and inertia together are both responsible for(1 point)
Responses
eclipses
eclipses
phases
phases
tides
tides
orbits
orbits
Question 12
This table shows the mass of four planets. What is the order of the planets showing the greatest gravitational pull to the least?
Planet Mass (1024kg)
Venus 4.87
Earth 5.97
Jupiter 1898.00
Neptune 102.00
Which shows the correct order of the planets when listed from the greatest gravitational pull to the least?
(1 point)
Responses
Earth → Venus → Neptune → Jupiter
Earth → Venus → Neptune → Jupiter
Jupiter → Earth → Venus → Neptune
Jupiter → Earth → Venus → Neptune
Jupiter → Neptune → Earth → Venus
Jupiter → Neptune → Earth → Venus
Neptune → Venus → Earth → Jupiter
Neptune → Venus → Earth → Jupiter
Question 13
Which description best explains why the inner planets called terrestrial?(1 point)
Responses
They have no atmosphere.
They have no atmosphere.
They are small and highly dense.
They are small and highly dense.
They have Earthlike oceans.
They have Earthlike oceans.
They are visible from Earth.
They are visible from Earth.
Question 14
Which characteristic best describes what the outer planets share with each other?(1 point)
Responses
They have no moons that orbit them.
They have no moons that orbit them.
They are made mostly of gaseous materials.
They are made mostly of gaseous materials.
They are all very warm, similar to Venus.
They are all very warm, similar to Venus.
They orbit the Sun opposite to Earth.
They orbit the Sun opposite to Earth.
Question 15
Earth is capable of supporting life, unlike many other planets because (1 point)
Responses
Earth's hydrosphere and atmosphere help maintain the conditions necessary to sustain life.
Earth's hydrosphere and atmosphere help maintain the conditions necessary to sustain life.
Earth has a gaseous atmosphere for only a part of the year.
Earth has a gaseous atmosphere for only a part of the year.
Earth is a terrestrial body.
Earth is a terrestrial body.
Earth is located inside the asteroid belt.
Earth is located inside the asteroid belt.
Question 16
The chart below shows the planets' diameters in the Solar System relative to Earth's diameter.
Looking at the chart, how does Earth's diameter compare to Venus?(1 point)
Responses
Earth is about twice the size of Venus.
Earth is about twice the size of Venus.
Earth is about one-ninth the size of Venus.
Earth is about one-ninth the size of Venus.
Earth is about nine times larger than Venus.
Earth is about nine times larger than Venus.
Earth is about the same size as Venus.
Earth is about the same size as Venus.
Question 17
What is the correct order of the structures list below from largest to smallest?(1 point)
Responses
universe, solar system, galaxy, planet
universe, solar system, galaxy, planet
universe, galaxy, solar system, planet
universe, galaxy, solar system, planet
solar system, universe, planet, galaxy
solar system, universe, planet, galaxy
planet, galaxy, solar system, universe
planet, galaxy, solar system, universe
Question 18
The table shows the primary gases in the composition of four planets.
Planet Jupiter Saturn Uranus Neptune
Atmospheric
Composition 90% hydrogen
10% helium
0.3% methane 90% hydrogen
3.5% helium
0.5% methane 83% hydrogen
15% helium
2% methane
80% hydrogen
19% helium
2% methane
Using the table, which planets have the most similar atmospheres?
(1 point)
Responses
Jupiter and Saturn
Jupiter and Saturn
Uranus and Neptune
Uranus and Neptune
Saturn and Uranus
Saturn and Uranus
Jupiter and Neptune
Jupiter and Neptune
Question 19
Nicolaus Copernicus developed the theory of a heliocentric solar system in the 1500s. One hundred years later, Galileo Galilei invented the telescope was able to provide scientific evidence to support this theory. What kind of scientific evidence did Galileo provide for Copernicus's theory?(1 point)
Responses
educated predictions
educated predictions
exact measurements
exact measurements
reliable observations
reliable observations
modern photographs
modern photographs
Question 20
Ptolemy and Copernicus were early astronomers. Ptolemy believed that Earth was the center of the solar system, and Copernicus believed that the Sun was the center of the solar system. Which model below would the astronomers most likely use to support their beliefs?(1 point)
Responses
Ptolemy and Copernicus would both use the geocentric model.
Ptolemy and Copernicus would both use the geocentric model.
Ptolemy and Copernicus would both use the heliocentric model
Ptolemy and Copernicus would both use the heliocentric model
Ptolemy would use the geocentric model and Copernicus would use the heliocentric model.
Ptolemy would use the geocentric model and Copernicus would use the heliocentric model.
Ptolemy would use the heliocentric model and Copernicus would use the geocentric model.
Responses
an atomic force
an atomic force
gravity
gravity
a tidal force
a tidal force
friction
friction
Question 10
Which of the following statements best describes the Moon's gravitational pull?(1 point)
Responses
The gravitational pull on the side Earth faces is stronger.
The gravitational pull on the side Earth faces is stronger.
The gravitational pull on the side Earth faces is weaker.
The gravitational pull on the side Earth faces is weaker.
The strength of the gravitational pull depends on the season.
The strength of the gravitational pull depends on the season.
The strength of the gravitational pull depends on the time of day.
The strength of the gravitational pull depends on the time of day.
Question 11
The forces of gravity and inertia together are both responsible for(1 point)
Responses
eclipses
eclipses
phases
phases
tides
tides
orbits
orbits
Question 12
This table shows the mass of four planets. What is the order of the planets showing the greatest gravitational pull to the least?
Planet Mass (1024kg)
Venus 4.87
Earth 5.97
Jupiter 1898.00
Neptune 102.00
Which shows the correct order of the planets when listed from the greatest gravitational pull to the least?
(1 point)
Responses
Earth → Venus → Neptune → Jupiter
Earth → Venus → Neptune → Jupiter
Jupiter → Earth → Venus → Neptune
Jupiter → Earth → Venus → Neptune
Jupiter → Neptune → Earth → Venus
Jupiter → Neptune → Earth → Venus
Neptune → Venus → Earth → Jupiter
Neptune → Venus → Earth → Jupiter
Question 13
Which description best explains why the inner planets called terrestrial?(1 point)
Responses
They have no atmosphere.
They have no atmosphere.
They are small and highly dense.
They are small and highly dense.
They have Earthlike oceans.
They have Earthlike oceans.
They are visible from Earth.
They are visible from Earth.
Question 14
Which characteristic best describes what the outer planets share with each other?(1 point)
Responses
They have no moons that orbit them.
They have no moons that orbit them.
They are made mostly of gaseous materials.
They are made mostly of gaseous materials.
They are all very warm, similar to Venus.
They are all very warm, similar to Venus.
They orbit the Sun opposite to Earth.
They orbit the Sun opposite to Earth.
Question 15
Earth is capable of supporting life, unlike many other planets because (1 point)
Responses
Earth's hydrosphere and atmosphere help maintain the conditions necessary to sustain life.
Earth's hydrosphere and atmosphere help maintain the conditions necessary to sustain life.
Earth has a gaseous atmosphere for only a part of the year.
Earth has a gaseous atmosphere for only a part of the year.
Earth is a terrestrial body.
Earth is a terrestrial body.
Earth is located inside the asteroid belt.
Earth is located inside the asteroid belt.
Question 16
The chart below shows the planets' diameters in the Solar System relative to Earth's diameter.
Looking at the chart, how does Earth's diameter compare to Venus?(1 point)
Responses
Earth is about twice the size of Venus.
Earth is about twice the size of Venus.
Earth is about one-ninth the size of Venus.
Earth is about one-ninth the size of Venus.
Earth is about nine times larger than Venus.
Earth is about nine times larger than Venus.
Earth is about the same size as Venus.
Earth is about the same size as Venus.
Question 17
What is the correct order of the structures list below from largest to smallest?(1 point)
Responses
universe, solar system, galaxy, planet
universe, solar system, galaxy, planet
universe, galaxy, solar system, planet
universe, galaxy, solar system, planet
solar system, universe, planet, galaxy
solar system, universe, planet, galaxy
planet, galaxy, solar system, universe
planet, galaxy, solar system, universe
Question 18
The table shows the primary gases in the composition of four planets.
Planet Jupiter Saturn Uranus Neptune
Atmospheric
Composition 90% hydrogen
10% helium
0.3% methane 90% hydrogen
3.5% helium
0.5% methane 83% hydrogen
15% helium
2% methane
80% hydrogen
19% helium
2% methane
Using the table, which planets have the most similar atmospheres?
(1 point)
Responses
Jupiter and Saturn
Jupiter and Saturn
Uranus and Neptune
Uranus and Neptune
Saturn and Uranus
Saturn and Uranus
Jupiter and Neptune
Jupiter and Neptune
Question 19
Nicolaus Copernicus developed the theory of a heliocentric solar system in the 1500s. One hundred years later, Galileo Galilei invented the telescope was able to provide scientific evidence to support this theory. What kind of scientific evidence did Galileo provide for Copernicus's theory?(1 point)
Responses
educated predictions
educated predictions
exact measurements
exact measurements
reliable observations
reliable observations
modern photographs
modern photographs
Question 20
Ptolemy and Copernicus were early astronomers. Ptolemy believed that Earth was the center of the solar system, and Copernicus believed that the Sun was the center of the solar system. Which model below would the astronomers most likely use to support their beliefs?(1 point)
Responses
Ptolemy and Copernicus would both use the geocentric model.
Ptolemy and Copernicus would both use the geocentric model.
Ptolemy and Copernicus would both use the heliocentric model
Ptolemy and Copernicus would both use the heliocentric model
Ptolemy would use the geocentric model and Copernicus would use the heliocentric model.
Ptolemy would use the geocentric model and Copernicus would use the heliocentric model.
Ptolemy would use the heliocentric model and Copernicus would use the geocentric model.
Ptolemy would use the geocentric model and Copernicus would use the heliocentric model.
Which word describes how the planets are held in Earth's solar system together?(1 point)
Responses
an atomic force
an atomic force
gravity
gravity
a tidal force
a tidal force
friction
Responses
an atomic force
an atomic force
gravity
gravity
a tidal force
a tidal force
friction
gravity
Which of the following statements best describes the Moon's gravitational pull?(1 point)
Responses
The gravitational pull on the side Earth faces is stronger.
The gravitational pull on the side Earth faces is stronger.
The gravitational pull on the side Earth faces is weaker.
The gravitational pull on the side Earth faces is weaker.
The strength of the gravitational pull depends on the season.
The strength of the gravitational pull depends on the season.
The strength of the gravitational pull depends on the time of day.
Responses
The gravitational pull on the side Earth faces is stronger.
The gravitational pull on the side Earth faces is stronger.
The gravitational pull on the side Earth faces is weaker.
The gravitational pull on the side Earth faces is weaker.
The strength of the gravitational pull depends on the season.
The strength of the gravitational pull depends on the season.
The strength of the gravitational pull depends on the time of day.
The gravitational pull on the side Earth faces is stronger.
The forces of gravity and inertia together are both responsible for(1 point)
Responses
eclipses
eclipses
phases
phases
tides
tides
orbits
Responses
eclipses
eclipses
phases
phases
tides
tides
orbits
orbits
This table shows the mass of four planets. What is the order of the planets showing the greatest gravitational pull to the least?
Planet Mass (1024kg)
Venus 4.87
Earth 5.97
Jupiter 1898.00
Neptune 102.00
Planet Mass (1024kg)
Venus 4.87
Earth 5.97
Jupiter 1898.00
Neptune 102.00
The correct order of the planets from the greatest gravitational pull to the least, based on their mass, is:
Jupiter → Earth → Neptune → Venus
Jupiter → Earth → Neptune → Venus
Which shows the correct order of the planets when listed from the greatest gravitational pull to the least?
(1 point)
Responses
Earth → Venus → Neptune → Jupiter
Earth → Venus → Neptune → Jupiter
Jupiter → Earth → Venus → Neptune
Jupiter → Earth → Venus → Neptune
Jupiter → Neptune → Earth → Venus
Jupiter → Neptune → Earth → Venus
Neptune → Venus → Earth → Jupiter
(1 point)
Responses
Earth → Venus → Neptune → Jupiter
Earth → Venus → Neptune → Jupiter
Jupiter → Earth → Venus → Neptune
Jupiter → Earth → Venus → Neptune
Jupiter → Neptune → Earth → Venus
Jupiter → Neptune → Earth → Venus
Neptune → Venus → Earth → Jupiter
Jupiter → Earth → Venus → Neptune
Which description best explains why the inner planets called terrestrial?(1 point)
Responses
They have no atmosphere.
They have no atmosphere.
They are small and highly dense.
They are small and highly dense.
They have Earthlike oceans.
They have Earthlike oceans.
They are visible from Earth.
Responses
They have no atmosphere.
They have no atmosphere.
They are small and highly dense.
They are small and highly dense.
They have Earthlike oceans.
They have Earthlike oceans.
They are visible from Earth.
They are small and highly dense.
Which characteristic best describes what the outer planets share with each other?(1 point)
Responses
They have no moons that orbit them.
They have no moons that orbit them.
They are made mostly of gaseous materials.
They are made mostly of gaseous materials.
They are all very warm, similar to Venus.
They are all very warm, similar to Venus.
They orbit the Sun opposite to Earth.
Responses
They have no moons that orbit them.
They have no moons that orbit them.
They are made mostly of gaseous materials.
They are made mostly of gaseous materials.
They are all very warm, similar to Venus.
They are all very warm, similar to Venus.
They orbit the Sun opposite to Earth.
They are made mostly of gaseous materials.
Earth is capable of supporting life, unlike many other planets because (1 point)
Responses
Earth's hydrosphere and atmosphere help maintain the conditions necessary to sustain life.
Earth's hydrosphere and atmosphere help maintain the conditions necessary to sustain life.
Earth has a gaseous atmosphere for only a part of the year.
Earth has a gaseous atmosphere for only a part of the year.
Earth is a terrestrial body.
Earth is a terrestrial body.
Earth is located inside the asteroid belt.
Responses
Earth's hydrosphere and atmosphere help maintain the conditions necessary to sustain life.
Earth's hydrosphere and atmosphere help maintain the conditions necessary to sustain life.
Earth has a gaseous atmosphere for only a part of the year.
Earth has a gaseous atmosphere for only a part of the year.
Earth is a terrestrial body.
Earth is a terrestrial body.
Earth is located inside the asteroid belt.
Earth's hydrosphere and atmosphere help maintain the conditions necessary to sustain life.
Looking at the chart, how does Earth's diameter compare to Venus?(1 point)
Responses
Earth is about twice the size of Venus.
Earth is about twice the size of Venus.
Earth is about one-ninth the size of Venus.
Earth is about one-ninth the size of Venus.
Earth is about nine times larger than Venus.
Earth is about nine times larger than Venus.
Earth is about the same size as Venus.
Responses
Earth is about twice the size of Venus.
Earth is about twice the size of Venus.
Earth is about one-ninth the size of Venus.
Earth is about one-ninth the size of Venus.
Earth is about nine times larger than Venus.
Earth is about nine times larger than Venus.
Earth is about the same size as Venus.
Earth is about the same size as Venus.
What is the correct order of the structures list below from largest to smallest?(1 point)
Responses
universe, solar system, galaxy, planet
universe, solar system, galaxy, planet
universe, galaxy, solar system, planet
universe, galaxy, solar system, planet
solar system, universe, planet, galaxy
solar system, universe, planet, galaxy
planet, galaxy, solar system, universe
Responses
universe, solar system, galaxy, planet
universe, solar system, galaxy, planet
universe, galaxy, solar system, planet
universe, galaxy, solar system, planet
solar system, universe, planet, galaxy
solar system, universe, planet, galaxy
planet, galaxy, solar system, universe
universe, galaxy, solar system, planet
The table shows the primary gases in the composition of four planets.
Planet Jupiter Saturn Uranus Neptune
Atmospheric
Composition 90% hydrogen
10% helium
0.3% methane 90% hydrogen
3.5% helium
0.5% methane 83% hydrogen
15% helium
2% methane
80% hydrogen
19% helium
2% methane
Planet Jupiter Saturn Uranus Neptune
Atmospheric
Composition 90% hydrogen
10% helium
0.3% methane 90% hydrogen
3.5% helium
0.5% methane 83% hydrogen
15% helium
2% methane
80% hydrogen
19% helium
2% methane
Using the table, the planets that have the most similar atmospheres are Jupiter and Saturn.
Using the table, which planets have the most similar atmospheres?
(1 point)
Responses
Jupiter and Saturn
Jupiter and Saturn
Uranus and Neptune
Uranus and Neptune
Saturn and Uranus
Saturn and Uranus
Jupiter and Neptune
(1 point)
Responses
Jupiter and Saturn
Jupiter and Saturn
Uranus and Neptune
Uranus and Neptune
Saturn and Uranus
Saturn and Uranus
Jupiter and Neptune
Jupiter and Saturn
Nicolaus Copernicus developed the theory of a heliocentric solar system in the 1500s. One hundred years later, Galileo Galilei invented the telescope was able to provide scientific evidence to support this theory. What kind of scientific evidence did Galileo provide for Copernicus's theory?(1 point)
Responses
educated predictions
educated predictions
exact measurements
exact measurements
reliable observations
reliable observations
modern photographs
Responses
educated predictions
educated predictions
exact measurements
exact measurements
reliable observations
reliable observations
modern photographs
reliable observations
Ptolemy and Copernicus were early astronomers. Ptolemy believed that Earth was the center of the solar system, and Copernicus believed that the Sun was the center of the solar system. Which model below would the astronomers most likely use to support their beliefs?(1 point)
Responses
Ptolemy and Copernicus would both use the geocentric model.
Ptolemy and Copernicus would both use the geocentric model.
Ptolemy and Copernicus would both use the heliocentric model
Ptolemy and Copernicus would both use the heliocentric model
Ptolemy would use the geocentric model and Copernicus would use the heliocentric model.
Ptolemy would use the geocentric model and Copernicus would use the heliocentric model.
Ptolemy would use the heliocentric model and Copernicus would use the geocentric model.
Responses
Ptolemy and Copernicus would both use the geocentric model.
Ptolemy and Copernicus would both use the geocentric model.
Ptolemy and Copernicus would both use the heliocentric model
Ptolemy and Copernicus would both use the heliocentric model
Ptolemy would use the geocentric model and Copernicus would use the heliocentric model.
Ptolemy would use the geocentric model and Copernicus would use the heliocentric model.
Ptolemy would use the heliocentric model and Copernicus would use the geocentric model.
Ptolemy would use the geocentric model and Copernicus would use the heliocentric model.