PLANETARY GEOLOGY
(100 points)


PURPOSE: to learn about the terrestrial planets and the methods used to analyze them

MATERIALS: calculator, ruler, terrestrial planet images

INSTRUCTIONS: complete your prelab, print out these pages and complete the activities below



SECTION 2 ACTIVITIES :

2.1. (1 pt) The terrestrial planets and most outer planet moons are:

 a)   solid bodies made of rock and metal
 b)   gaseous bodies composed of various gases
 c)   solid bodies with no atmospheres
 d)   the major component of the Solar System


2.2. (1 pt) Mercury's surface is :

 a)   extremely hot with a thick atmosphere
 b)   similar to Earth's surface
 c)   extremely hot and heavily cratered
 d)   covered by many volcanos


2.3. (1 pt) 80% of Venus' surface is :

 a)   cratered
 b)   covered by mountain ranges
 c)   covered by volcanic plains
 d)   made of iron oxide (a.k.a. rust)


2.4. (1 pt) The Earth's surface is unique because it :

 a)   is covered by many large impact craters
 b)   is composed of rocks and metals
 c)   never changes
 d)   is constantly changing due to weather and tectonic activity


2.5. (1 pt) Mars' surface is :

 a)   covered by many volcanos and canyons
 b)   covered over by a thick atmosphere
 c)   covered by canals and rivers
 d)   featureless


2.6. (1 pt) The Galilean moons are :

 a)   the largest moons of the Solar System
 b)   the largest moons of Saturn
 c)   the largest moons of Jupiter
 d)   the oldest moons of the Solar System


2.7. (1 pt) The Galilean moon Io is known for :

 a)   its large size
 b)   its massive volcanic activity
 c)   its layer of ice
 d)   its surface features


2.8. (1 pt) The Galilean moon Europa is known for :

 a)   its large size
 b)   its massive volcanic activity
 c)   its layer of ice
 d)   its surface features

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**EXPERIMENT**
Here we will examine some class photographs to learn more about planetary surfaces. Your TA has set up some class images #1 - 6. Go to the demo table and examine the images to answer these questions:

2.9. (4 pts) Examine class Images #1 (Mercury), #2 (Venus), and #4 and #5(Mars). Note that in the Venus image the coloring is "false color" - ignore it. List several ways in which these planetary surfaces are similar. Then for each planet, list one way it is unique.










2.10. (4 pts) Examine class Image #6 of the Galilean moons. For each, describe its surface (color, texture, number and types of features, etc.)









2.11. (1 pt) Now examine class Image #3 of Earth. How does its surface compare to the other terrestrial planets and the Galilean moons?









SECTION 3 ACTIVITIES :

3.1. (2 pts) Using data from Table 1 in the lab text, find the surface temperature (TS) for Earth in degrees K.








Wow, that’s hot! This result corresponds to a possible maximum noontime temperature here on Earth of about 170 °F. Fortunately, our atmosphere protects us, blocking out a lot of sunlight from ever reaching the surface, and thus, actually keeping it cooler than our calculation. Can you imagine what we would do if it actually got that hot?!?!


3.2. (2 pts) Now calculate the surface temperature for Mercury (in degrees K).








3.3. (2 pts) How many times hotter is Mercury than Earth?






3.4. (2 pts) Pluto's surface temperature is about 57.3 K. How many times cooler is Pluto than Earth?






3.5. (3 pts) The abundance ratio of K/Ar in the famous ALH 84001 meteorite from Mars is 7.87. The half-life for K-40 is t = 1.28 x 109 yrs. Find how long ago this rock was formed on Mars?








3.6. (3 pts) A rock and soil sample taken from the lunar highlands has a Rb/Sr ratio of 0.0662. Rubidium has a half-life of t = 4.748 x 1010 yrs. Estimate the age of this sample, and thus, the age of the Moon.








3.7. (1 pt) What conclusion can you draw about the age of the Solar System from your above results?





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**EXPERIMENT**
Here you will use a photograph to see how we estimate the sizes of surface features. Obtain Image #7 (Mars Tharsis region) from the TA and a ruler.

3.8.   Notice the three similar sized volcanoes in a straight line across the center of the planet. The center volcano, Pavonis Mons, is representative of most Martian volcanoes.

a) (1 pt) Measure the distance (T) from the center of Pavonis Mons to th terminator.

T = _______________ cm


b) (1 pt) Now measure the length of the shadow (S) extending off to the left of this volcano.

S = _______________ cm


c) (1 pt) The image plate scale is P = 8.849 cm. Find the scaled height (SD) of the volcano.







d) (2 pts) The radius of Mars is R = 3393 km. Use this along with your result from part c) to now
calculate the volcano's true height (D). (in km).









3.9. (2 pts) The largest volcano on Earth is Mauna Loa (10 km). How many times larger is Pavonis Mons?







3.10.   Now examine Image #8 - a close-up of the Tharsis region and Pavonis Mons (center).

a) (1 pt) Notice the map scale indicator at the bottom lefthand corner. Use this to ESTIMATE the diameter of Pavonis Mons (in km).

b) (1 pt) Now, actually measure the diameter of this surface feature (in mm).

diameter = _______________ mm


c) (2 pts) The exact image scale is 0.085 mm / km. Use this to calculate the true diameter of this volcano.







3.11.   Now return to class Image #4 of Mars taken by the Viking orbiter 1 in 1976. Across the center of the planet we see the large canyon system called Valles Marineris.

a) (1 pt) Measure the diameter of Mars (in cm).

diameter = _______________ cm


b) (1 pt) Now measure the length of Valles Marineris (include the darkened areas and all the connecting canyons on the left).

length = _______________ cm


c) (2 pts) If Mars' real diameter is about 4222 miles, set up ratios to calculate how long the Valles Marineris is (in miles).







d) (2 pts) What percentage of Mars diameter is covered by this canyon system?





e) (1 pt) The Grand Canyon on Earth is about 18 miles wide and 1 mile deep. Valles Marineris is about 125 miles wide and 4 miles deep. How much wider and deeper is Valles Marineris than the Grand Canyon? [Hint: you do not have to show a calculation here...just estimate the answers]









SECTION 4 ACTIVITIES :

4.1. (1 pt) Tectonic activity is :

 a)   the transport of molten material from the interior of a planet to its surface
 b)   the large scale movement of a planet's crust
 c)   the alteration of a planet's surface by erosion
 d)   the collision of meteors and other objects with a planet's surface


4.2. (1 pt) Gradation is :

 a)   the transport of molten material from the interior of a planet to its surface
 b)   the large scale movement of a planet's crust
 c)   the alteration of a planet's surface by erosion
 d)   the collision of meteors and other objects with a planet's surface


4.3. (1 pt) Impact cratering is :

 a)   the transport of molten material from the interior of a planet to its surface
 b)   the large scale movement of a planet's crust
 c)   the alteration of a planet's surface by erosion
 d)   the collision of meteors and other objects with a planet's surface


4.4. (1 pt) Volcanism is :

 a)   the transport of molten material from the interior of a planet to its surface
 b)   the large scale movement of a planet's crust
 c)   the alteration of a planet's surface by erosion
 d)   the collision of meteors and other objects with a planet's surface

--------------------------------------------------
**EXPERIMENT**
Examine various planet/moon images to compare their geologic surface features. Go to this website. Notice that the images are grouped into categories : volcanism, impacting, and gradation (split into groups for wind and water/ice).

4.5. (2 pts) Click on 'Volcanoes'. Examine the images of Olympus Mons, Mt. St. Helens, and Sapas Mons. These 3 volcanoes are all located on different planets. List at least 2 identifying characteristics which indicate these features were created by volcanism.






4.6. (2 pts) Go back to the main page. Examine the images in 'Wind' and 'Water & Ice'. These features were are all located on different planets/moons. List at least 2 identifying characteristics which indicate these features were created by gradation.






4.7. (2 pts) Go back to the main page. Click on 'Impact' and examine all the images. These features were are all located on different planets/moons. List at least 2 identifying characteristics which indicate these features were created by impacting.






4.8.   Use the following data to answer the questions below about impact cratering:

vESC(Earth) = 1.12 x 104 m/s      gT = 9.81 m/s2      rT(Earth) = 5520 kg/m3

a) (3 pts) If a meteor approaches Earth with a speed of vAPP = 1.5 x 104 m/s, what will its speed of impact be?







b) (3 pts) The meteor has a mass of 1500 kg. What is the kinetic energy of this impact? [Note: the units you end up with, together, are called a Joule (J)]







c) (3 pts) If the meteor has a density of r0 = 3500 kg/m3, a diameter of d0 = 1000 m, and hits the surface at an angle of θ = 51°, what will be the approximate diameter D of the impact crater (in meters) left behind?








-------------------------------------------------
**EXPERIMENT**
Let's learn about possible impact cratering scenarios through calculations and by using the "Computing Crater Size..." applet, © H.J Melosh & R.A. Beyer.

Go to the applet's website. Notice that you can select specific data for the projectile object, the impact conditions, and the solid target object it will hit. In the pull down menus, notice that you can choose between four different material densities for the impactor and target objects - ice, porous rock, dense rock, or iron. These are the most common compositions for known asteroids, meteors, and comets found in our Solar System.

4.9.   First, let's compare our impact calculations in #4.8 to the applet's calculations using the same data as listed below:

projectile diameter :      1000
projectile density :      3500
impact velocity :      18.72
impact angle :      51°
target density :      5520
accl. of gravity :      9.81

a) (3 pts) Enter the above data into the applet. For 'target type', enter 'competent rock or saturated soil' and press 'Calculate'. Record your results in the table below. Following this, also run the same experiment but for the other 2 'target types'. Enter the results in the table as well.

target type Crater Formation Time (seconds) Diameter D (meters) Energy KE (Joules)
competent rock or
saturated soil		               
loose sand
 		               
liquid water
  		              


b) (2 pts) List 2 possible reasons for the discrepancy between our crater diameter and impact energy calculations and those of the applet.






c) (1 pt) How does the target's surface composition (solid vs. malleable) change the time of formation and the resulting crater diameter in general?


4.10. Now, experiment some more with this applet by trying a different scenario : object hits different planets/moons. Enter the following data into the applet:

projectile diameter :      1000
projectile density :      3500
impact velocity :      18.72
impact angle :      51°
target type :     competent rock or saturated soil

a) (3 pts) For the following combinations of target density and gravity, select them in the applet (use the pull down menu bars to see the options) and press 'Calculate'. Record your results below:

target density (kg/m3) accl. of gravity (m/s2) Crater Formation Time (seconds) Diameter D (meters) Energy KE (Joules)
5520 for Earth 9.8 for Earth 1.91 x 101 2.16 x 104 3.21 x 1020
3000 for dense rock 8.9 for venus               
3000 for dense rock 3.7 for Mars               
1000 for ice 1.8 for Io               
1500 for porous rock 1.4 for Titan               


b) (1 pt) Do you observe any relationships between density, acceleration of gravity, formation time, and/or crater diameter? If so, describe the relationship(s).





4.11. (1 pt) In both #4.9 and #4.10 you may have noticed that the energy did not change despite the changes in the impact target. Why did the impact energy remain the same?





The largest atomic bomb humans have ever exploded let out 50 Megatons of energy. Compare this to the energy calculated by this applet: 7.67 x 104 Megatons. That means that a typical meteor impact on Earth or another terrestrial type Solar System body would release over 1500 times more energy than an atomic bomb explosion can. Wow!


4.12.   Lastly, re-enter the following data into the applet:

impact velocity :      18.72
impact angle :      51°
target density :      5520
accl. of gravity :      9.81
target type :     competent rock or saturated soil

a) (1 pt) Experiment with changing the projectile's diameter. How does the resulting crater diameter change as you increase the size of the impact object?



b) (1 pt) Now, repeatedly experiment again. How does the resulting crater diameter change as you increase the projectile's density?




4.13. (3 pts) List at least 3 reasons why the analysis of geological processes is important in studying the formation and evolution of the Solar System.













* TURN IN THESE ACTIVITIES PAGES TO YOUR TA*  

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