PSC 151
Exercise
Comparative Planetology
http://www.cnrt.scsu.edu/courses/psc150/psc_153/Compare_Planets.html
http://www.cnrt.scsu.edu/courses/psc150/psc_153/Compare_Planets.DOC
Name ___________________________
Introduction:
Comparative Planetology is the study of the planets focused on comparisons of properties and
features. It looks for both similarities and differences between the planets to come to a deeper
understanding of their nature.
Part 1: Appearance
Goals:
- examine and describe the visual appearance of the planets
- classify planets based on appearance
We start by looking at the physical appearance of each of the planets using the website listed
below.
http://www.nineplanets.org/
. For each planet click on the links below its name to see images of the planet, describe the
general appearance of each planet including all major features. Please be descriptive and
thorough.
DO NOT write down facts you know about the planets. Write down what you SEE in the
photographs
1) Mercury
1) Surface of Mercury:
http://nssdc.gsfc.nasa.gov/image/planetary/mercury/mercuryglobe2.jpg
2) Venus
1) Atmosphere:
http://www.solarviews.com/browse/venus/venusmar.jpg
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2) False color image of surface, colors indicate elevation- Blue: deep basins, Green: coastal
plains, Red/Orange: highlands and mountains.
http://www.solarviews.com/browse/venus/venus1.jpg
3) Earth
1) Showing the African Continent
http://www.solarviews.com/raw/earth/earthafr.jpg
4) Mars
1) Dry river valleys
http://www.solarviews.com/raw/mars/network.gif
2) Valles Marineris
http://www.msss.com/mars/pictures/usgs_color_mosaics/marineris.gif
3) Viking 2 Landing Site
http://pds.jpl.nasa.gov/planets/captions/mars/vlpan22.htm
4) Olympus Mons
http://pds.jpl.nasa.gov/planets/captions/mars/olympus.htm
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5) Jupiter
1) Cloud bands and Giant Red Spot
http://photojournal.jpl.nasa.gov/jpegMod/PIA02873_modest.jpg
2) Close-up of Red Spot
http://pds.jpl.nasa.gov/planets/captions/jupiter/febgrs.htm
3) Jupiter and its four largest (Galilean) moons
http://www2.jpl.nasa.gov/galileo/ganymede/PIA00600_full.jpg
6) Saturn
1) Saturn partially eclipsing its ring system
http://www.solarviews.com/browse/sat/saturnb.jpg
2) Saturn's rings and two of its moon
http://pds.jpl.nasa.gov/planets/captions/saturn/tethdion.htm
3) False color image of rings
http://nssdc.gsfc.nasa.gov/image/planetary/saturn/saturn_rings_false.jpg
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7) Uranus
1. Atmosphere of Uranus
http://www.solarviews.com/browse/uranus/uranus.jpg
2. Rings around Uranus
http://hubblesite.org/newscenter/archive/releases/1996/15/image/a/format/web_print/
8) Neptune
1) Neptune's atmosphere showing clouds
http://pds.jpl.nasa.gov/planets/captions/neptune/fullnep.htm
2) Neptune's rings
http://pds.jpl.nasa.gov/planets/captions/neptune/neprings.htm
9) Pluto (Dwarf planet}
1) Pluto (Left) and its moon Charon
http://imgsrc.hubblesite.org/hu/db/images/hs-1994-17-a-full_jpg.jpg
Part 2: Mass, Volume, and Density
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Goals:
- calculate the volume of the planets
- calculate the density of the planets
- organize planets based on mass, volume, and density
Terms:
 Radius – the distance from the center of an object to its edge
 Volume – the amount space an object takes up
 Mass – the amount of matter contained in an object
 Density – a measure of how compact matter is, the mass divided by the volume
Data Table 1 contains a list of the radius and mass of each planet compared to Earth. These
relative values are not in the normal metric units you are used to seeing.
1) Use the radius of each planet to calculate the normalized volume (V=r3). Fill these values
into Data Table 1 on the next page.
2) Use the mass and calculated volume of each planet to calculate the normalized density.
Fill these values into the t Data Table 1.
Example : Mercury
M mercury  0.055
rmercury  0.382
Vmercury  0.3823  0.056
Dmercury 
M mercury
 0.055  0.982
Vmercury
0.056
Data Table 1: Radius and Mass of the Planets compared to Earth
Volume, V
Density, D
Mass, m
Radius, r
V = r3
D = Mass/Volume
(Earth=1)
(Earth=1)
(Earth=1)
(Earth=1)
Mercury
0.055
0.382
0.056
0.982
Venus
0.815
0.949
Earth
1.00
1.00
Mars
0.107
0.532
Jupiter
318
11.21
Saturn
95
9.44
Uranus
15
4.01
Neptune
17
3.88
Pluto
0.002
0.180
Planet
3) Which planet has the smallest volume?_________________
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4) Which planet has the largest volume?_________________
5) Which planet has the lowest density?_________________
6) Which planet has the highest density?_________________
7) If you were to list the planets in order of increasing mass, would it be the same order as
increasing density? __________________
Part 3: Surface Gravity
Goals:
- examine and classify planets based on their surface gravity
- determine your weight on the other planets
- identify sample weights with the corresponding planets gravity
Terms:
 Surface gravity – the acceleration of an object due to the gravity at the surface of a planet
 Weight – the force due to the gravity that an object experiences
Weight = mass x acceleration due to gravity
1) Using the definition of surface gravity and weight and the values in Data Table 2,
calculate your weight on each planet and fill in that row on the table.
Your Weight (Planetary) = Your Weight on the Earth  Planet' s Surface Gravity
Example : Mercury
If you weight 110lb on the earth. your weigth on Mercury would be
:
Weight Mercury  Weight Earth  Mercury' s' Surface Gravity
Weight Mercury  110lb 0.38  41.8lb
Data Table 2: Surface Gravity of the Planets Compared to Earth
Your weight on the Earth=________lbs
Mercury
Gravity
(Earth=1)
Student
Weight
0.38
Venus
Earth
Mars
Jupiter
Saturn
Uranus
0.90
1.00
0.38
2.64
0.93
0.89
Neptune
1.12
Pluto
0.06
2) If you were on Pluto, do you think you would be able to lift a car that weighs 1200lbs on
Earth?___________ _______________________
Part 4: Years
Goals:
- Compare the length of a “year” on each planet
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Terms:
 Planetary year(Orbital Period) – the length of time for a planet to go once around the Sun
 Earth year – the length of time for the Earth to go once around the Sun
1) Using the data in Table 3, calculate your age in planetary years for each of the planets and
fill this information into the column in Table 3.
Your Age
Your Age (Planetary Years) =
Planet' s Orbital Period
Example : Mercury
I am 61 years old. My age on Mercury would be
Age Earth
Orbital Period of Mercury
 61  254yrs
0.24
Age Mercury 
Age Mercury
Data Table 3: "Years" on other Planets
Your age now:______ yr
Planet
Mercury
Orbital Period
(Earth Years)
0.24
Venus
0.62
Earth
1.00
Mars
1.88
Jupiter
11.86
Saturn
29.46
Uranus
84.01
Neptune
164.8
Pluto
247.7
:
Your age (Planetary years)
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