Asking for directions on Mars
Purpose: Students will learn how to use an interactive online map of Mars — including working with coordinate systems and layers — and will identify features and make generalizations about Martian geography.
Procedural overview: After a review of latitude and longitude, students will explore NASA’s Mars Map, first through a tutorial and then on their own. Students will identify specific sites and will use the map’s interactive tools to learn more about the sites and locate nearby geographic features. Finally, students will make geographic generalizations about specific regions. Sites on Mars come from “A buried lake on Mars excited and baffled scientists,” “A year of launches and farewells in space” and even from the fictional film The Martian.
Approximate class time: One class period.
- Activity Guide for Students: Asking for Directions on Mars
- Access to NASA’s Mars Map
- Earth globe (for comparison with Mars and to help students understand latitude and longitude lines). Available from Amazon or other websites for $25.
- OPTIONAL: Sky & Telescope 12” Mars globe (to help visualize Mars as a sphere). Available from Shop at Sky, Amazon or other websites for about $100.
Directions for teachers:
Review the concepts of latitude and longitude with your students as necessary. The coordinate system works the same on Mars as on Earth. Lines of latitude run parallel to the equator and measure north-south position between the poles. Lines of longitude run through the north and south poles and measure east-west positions relative to the prime meridian. Demonstrate these concepts using the Earth globe (and the Mars globe if you have it).
Here are some general points to highlight:
- If you are looking at the planet’s surface with north upward and south downward, east is to the right and west is to the left. Both Earth and Mars rotate such that the sun appears to rise in the east and set in the west.
- Latitude is how many degrees north or south of the equator a location is; 90° N is the North Pole, and 90° S is the South Pole.
- Longitude is how many degrees east or west a location is relative to an arbitrarily defined prime meridian. The point 0°, 0° is where the prime meridian intersects the equator. 0°, 180° is on the exact opposite side of the planet, and is the point of intersection between the antimeridian and the equator. 270° E is the same as 90° W and so on.
Now it’s time for Mars. NASA’s Mars Map automatically begins with a nice tour that shows how to use the program. Make sure you get comfortable using the interactive yourself before shepherding your students through the site.
Directions for students:
Take the tutorial
Go to NASA’s Mars Map, take the tutorial and answer the following questions.
1. Briefly explain what each of the following buttons looks like and the actions it allows you to take.
2. What kind of information can you add to the map by applying each item listed below? How does the interactive map change when you add the item?
3. Where is map information such as scale and latitude/longitude coordinates displayed?
Begin to explore the map
Now explore some of the features mentioned in the tutorial by answering the following questions.
4. As you move your mouse across the map in Global Map view, what do you notice about the latitude and longitude coordinates? Which is listed first? How are they different from Earth’s coordinates? What does a negative latitude mean? What does a negative longitude mean? Why do you think that the interactive map uses the negative values?
5. What are the coordinates for the point where Mars’ equator intersects Mars’ prime meridian? What about the point where the equator intersects the antimeridian? Do these points have the same or different coordinates on Earth? What is the latitude of the prime meridian?
6. Go to the Layers panel and select “Static.” You can click the “Toggle Visibility” button (looks like an eye) for layers such as Nomenclature and Graticule. Using the Fly To button, type in only the longitude of the prime meridian. The name of the feature that defines the prime meridian’s location on Mars will appear below as you type. What is its name? Click on the feature’s name to find it on the map. Click on the Explorer button, find the name of the feature and click on it. The feature should be flagged on the map. Based on the map topography, what type of feature is it? You can check your answer by searching for the feature using the search panel.
7. In the same view (the scale should measure about 50 kilometers), click on the Explorer button. Identify a landing site within your view, name it and give its approximate coordinates. What other geographic features are within the view? Name one geographic feature and give its approximate diameter in miles (change the units of the scale, if necessary).
8. Using the Search panel, locate and “fly to” two other successful landing sites. Use the map topography and the Explorer button (when zoomed so the scale is approximately 50 km) to describe the geographic features near the site. Use the map tools available to give two other interesting facts about the site.
9. Using the Search panel, locate and “fly to” the Martian Path (from the fictional film The Martian). Describe the approximate size of the area shown. Use the map topography and the Explorer button to describe the geographic features in the area. On the Layers panel with “Static” selected, you can click the “Toggle Visibility” button (looks like an eye) to see more information. Imagine that you are in a rover near the Martian Path. Based on the information you have gathered, where would you travel and what would you expect to see during your journey and upon your arrival?
10. Finally, using the Fly To button, locate the site of the possible underground lake reported in the Science News article “A buried lake on Mars excited and baffled scientists,” at -81, -167 (or 81° S, 167° W). What do you notice about the limitations of Global Map view in this region? Is there a better map projection that you can use to view the area? Use the Explorer tool to name any geographic features nearby.
Make geographic generalizations
Now that you’re familiar with the map and some geographic features, you can form some generalizations.
11. Use the Projections button to toggle through different map projections. Make sure you have turned on Graticule in the Static Layer panel, so you can see the lines of latitude and longitude. Observe the geography in the regions listed below. Describe any patterns or predominate features that you see. Please note: In the 3D Globe view, you may want to adjust the “Terrain Exaggeration” so you are better able to distinguish geographic features.
North Pole region:
South Pole region:
12. If you could choose a location for a future lander or rover mission to Mars, where would you choose? What factors would you consider?
13. Would you sign up for the first human landing on Mars? Why or why not?
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