The Surface of Mars

Lab: The Surface of Mars

Abstract

In this lab, students study several images of Mars and use their observations to draw conclusions and make inferences as to how surface features came to be, why the elevation of the planet is so different between two hemispheres, and why scientists chose to land spacecraft where they did on Mars. Students also determine why some images of Mars look different from one another and what these differences can tell us.

Introduction

As our next-door-neighbor in the solar system, Mars has been a subject of observation of people on Earth for hundreds of years. While not all observations led to correct conclusions, as in the case of Percival Lowell, these observations have provided us with much information on the surface of Mars, including its differing features, compostion, and elevation.

Procedure

 Materials: Google Mars, maps and images provided with lab.

A: In part A, students examined sketches of the surface of Mars by Percival Lowell and compared them to two images of Mars taken by the Hubble Space Telescope in 2003. Students answered questions over the sketches and images.

B: In part B, students analyze two typical images of Mars that can be obtained with a telescope on the ground and answered questions over them.

C: Students are shown two images of Mars taken months apart and answer questions regarding the differences in the pictures.

D: In part D, students use maps to answer questions regarding Mars' elevation, cratering, and the landing sites of several missions to Mars.

E: Students use features on Google Mars to locate and examine the landing sites of the Mars Exploration Rovers. Students then answer questions on these landing sites, Niger Valles, and the information that maps of different wavelengths of light can give.

F: Students are given a link to view a webpage of NASA space missions. They are then asked to consider the goals of a mission to Mars if they were planning it.

Results and Discussions

A: 

Percival Lowell thought he was seeing evidence of advanced intelligent people on Mars, as evidenced by vast canals spanning the planet.

1. Why would Percival think he saw canals? 

      Lowell might have believed he saw canals because the dark lines in his drawings do, in fact, resemble canals which flow from a large body of water (large dark area) farther into the planet. This misconception is understandable because at the time of Lowell's observation, ships were a major mode of transportation, especially for the movement of goods. Therefore, the features on Mars' surface cause shadow or dark areas that somewhat resemble a water canal system on Earth.

2. What was Percival seeing instead?

     Lowell was seeing darker areas on the surface of Mars, which could represent a number of things, including changes in elevation and differences in composition, such as possible volcanic rock leftover from previous volcanic activity. 

B:

1. What are the main features that you can identify from the images taken from the surface of the Earth? What might they be caused or produced by? Can you see anything that resembles craters, mountains, or seas?

      In the two images of Mars, one can easily identify light and dark areas, which represent differences in elevation and composition. Also, one of the images shows a white area at Mars' south pole, which looks like a polar cap. These different light and dark areas could be caused by volcanic activity. The images do possess some semi-circular features that resemble craters, there are long strings of dark areas that resemble mountain ranges, and the dark/lower areas could indicate the existence of ancient seas on the surface of Mars. The images are very fuzzy, however, and it is difficult to identify anything with clarity.

2. How are these ground-based images similar to the Hubble Space Telescope image? How are they different? Why might our views of Mars be changing?

       The ground-based images and the Hubble Space Telescope image have similar colors, and corresponding areas in the images are generally the same shade of light or dark. That is,we view lightness and darkness on the surface in the same areas. The ground-based images lack the clarity afforded by the Hubble Space Telescope however, and it is much more difficult to identify  features in these images. Also, the images are all of different views of the surface of Mars, and these views show us different features. Our view of Mars changes because of the orbit and rotation of both Earth and Mars, which move at very different rates. Therefore, our perspective is constantly changing.

3. Does Mars have a lot of visiblee craters like the moon and Mercury? What does this mean?

    No, the surface of Mars does not have nearly as many craters as the moon or Mercury. This means that the surface of Mars is fairly new, and has been smoothed over since the violent period of collisions in our solar system.

4. The "S"-shaped sequence of Mars-shaped images clearly show Mars appearing to change in size. They were take over several months. What is going on?

      This image shows the changing perspective of Mars from the Earth as each planet continues on its respective orbit around the sun. The apparent retrograde motion in the middle if the image occurs when one planet laps the other in their orbits.

C:

1. What are the main features you can identify in these images? 

     There is a large, smooth, lighter area in the left image. This area seems to have some dark spots, which could be mountains. That area is surrounded by darker land. The north and south poles have some sort of ice. 

2. How are the two images similar and different?

    Both images show portions of this lighter, smooth area, which is then surrounded by darker matter. Both images reveal ice at the poles. While both images are slightly hazy, the left image has much more detail than the right image. Also, they are showing slightly different areas of the surface of Mars. 

3. What is going on here?

     The first image, taken in June, shows the surface of Mars in direct sunlight (the Sun is in front of Mars), The second image shows the light of the Sun coming from the right side. The light is much less direct, therefore, and the image is less detailed.

D:

1. What do the four highest features on Mars appear to be? What could that mean?

     The four highest features on Mars all appear to be volcanoes. This could mean that Mars has seen volcanic activity, which explains the young surface with few pockmarks. 

2. In the elevation map of the planet, what is the most notable difference between the Northern and Southern hemispheres? What might this mean?

The Northern hemisphere is much lower in elevation than the Southern hemisphere and contains very few craters, while the Southern hemisphere is moderately cratered. This might mean the the Northern hemisphere was once covered in a sea of liquid, explaining the lowered elevation and lack of craters. This could also mean that the Northern hemisphere has been recently resurfaced by molten rock.

3. Which hemisphere appears to have most of the impact craters?

    The Southern hemisphere contains most of the craters, with the south east quadrant of the provided elevation image being the most heavily-cratered area.

4. What appears to be the largest impact crater on Mars?

     Hellas Planitia appears to me to be the largest impact crater on Mars. 

5. Find the landing sites for the US Viking I and II spacecraft. What type of terrain did they land in?What do you think were the reasons for choosing these particular areas? From the elevation map, were they high or low elevation regions on the surface?

      The spacecraft landed in smooth areas on the younger portions of Mars' surface. These areas were probably chosen for the efficiency of landing a spacecraft on smooth terrain as well as to study the composition of newer parts of Mars' surface. Both spacecraft landed in areas of low to mid-low elevation.

6. Find the landing sites of the US Mars Pathfinder, Spirit, Opportunity and Curiosity spacecraft. What type of terrain did they land in? What could have been the reasons for choosing these areas?

Pathfinder - smooth, flat terrain; near the beginning of higher elevation. Most likely landed here to study composition of surface material.

Spirit - terrain less smooth, but not rough. Near a rift in the ground. This is the landing site to study the composition of surface material and the nature or history of the nearby feature in the ground.

Opportunity - landed in low-to-medium elevation, some cratering nearby. Probably landed here to study this surface that is younger than the oldest surfaces on Mars, but younger than the youngest surfaces in the Northern hemisphere.

Curiosity - rough terrain; landed near the equator at medium elevation; near the border between higher and lower elevation. This landing site was chosen to study the area between the extremes in elevation and to study the surface of Mars near its equator.

7. The Soviet Mars 3 spacecraft was the first soft landing on Mars. After 14.5 seconds, transmission from the surface stopped. Give a reasonable explanation as to why it may have fallen over. 

Mars 3 could have fallen over because there are many craters within the Ptolemaeus Crater, including tangential craters (with the rims touching). The presence of such cratering creates a rough terrain that would be easy for a spacecraft to tip over on.

E:

 Search for the landing sites of the Mars Exploration Rovers. They landed at Gusev Crater and Meridiani Terra. 

1. Describe each landing site, noting the features present and the elevation. Suggest reasons why these particular places might have been chosen.

Spirit: Gusev Crater - the landing site is smooth terrain, with low-to-medium elevation and more craters surrounding the site. This site was probably chosen for its proximity to a feature that looks like it may have once been a volcano.

Opportunity: Meridiani Terra - The terrain is somewhat smooth with some nearby craters. Again, low-to-medium elevation, but the landing site is on the border between lower elevation in the North and higher elevation in the South. This is probably one reason that this landing site was chosen, as well as its proximity to a mountain range and the ability to study surface composition. 

2. Look at each landing site in the visible and infrared and determine whether you can see things in one wavelength that you cannot see in the other. 

Spirit - In infrared, there exists a dark, cold area that resembles ice. The area streaks out in jagged, ice or frost-like patterns. This feature is much less noticeable in visible wavelengths, and appears only vaguely darker than the surrounding land. 

Opportunity - many of the areas that appear darker in visible light then appear brighter (indicating warmth) in infrared. This is interesting, and indicates that the lower elevation is warmer than the higher elevation. 

3. Search for Niger Valles on Google Mars. Follow this feature from its high elevation to its low elevation (beginning to end). What seems to be going on here?

   This feature resembles a valley cut into land by the flow of a liquid (maybe water) from a point of high elevation to low elevation. In other words, it resembles the path of a river.

F:

 If I were planning the next mission to Mars, its goals would be to investigate the history of water or water-ice on the Martian surface, to study the features that resemble the paths of rivers in order understand how they came to be, and to gather data to determine whether a permanent human settlement on Mars is a good idea.

Conclusion

By studying the surface of Mars, we can often gain answers to many questions, such as "what areas of the surface are younger than other areas?" and "what features do you observe, and how might they have came to be there?" However, observations can lead to even bigger, more mysterious questions. For instance, why is the Northern hemisphere of Mars at a much lower elevation than the Southern hemisphere? Was the north once covered by a sea of some sort, or is there another explanation? Unfortunately, not all questions can be answered right away, and many questions regarding Mars and its history require much more research before answers become clear. By studying the surface features, elevation, and composition of different areas of Mars, we are able to gather more data, make more inferences and conclusions, and ultimately learn more about Mars, which leads us closer to answering these big, mysterious, perhaps unanswerable questions.