Lab09-Identifying Surface Features from Space_21S(1) (1)

National Aeronautics and Space Administration Lab 9: Identifying Surface Features from Space Objective This activity will help you understand how to identify features on the surface of our planet and other objects in our solar system. This task will be accomplished by observing images taken from space. The images of Earth you will observe in this activity are credited to astronauts from the International Space Station or Space Shuttle, using hand-held cameras. Identifying surface features using images from space requires making attentive observations, being descriptive, and using prior knowledge about Earth to determine what is being shown in the images. In addition, you will need to explain what processes were involved in creating the features. You will then apply that knowledge to identify features on the surface of Mars. Background Information NASA explores planetary bodies, including Earth, to better understand the solar system in which we live. Various types of spacecraft and scientific instruments are used to explore and gather data. Scientists use the data returned from these spacecraft to make observations which they record, analyze, and interpret. One technique or process of gathering data from a distance using spacecraft, or even aircraft, is called remote sensing. Remote sensing allows us to gather data of a location we might not be able to visit in person. One application of remote sensing is using images to identify geologic features on Earth and different planets. The first part of this activity allows you to explore and discover visible features in astronaut photography acquired from space. There is a database of over 900,000 images available for the public to view images from space, available at the Gateway to Astronaut Photography of Earth website, http://eol.jsc.nasa.gov ; the images in this activity are a small subset of that collection. The activity builds on your prior knowledge about Earth and takes you through a procedure wherein you can recognize visible features of Earth and associate those features with a geologic process that occurs on the Earth’s surface. Planetary scientists who make observations of geologic features on Earth need to have useful ways to describe those features. This becomes especially important as they compare geologic features on Earth to features being observed on other planets. Below is a list of characteristics scientists often use to describe geologic features in images based on their observations. Descriptor characteristics: 1. Size: Features can be described in terms of actual or relative size. For a detailed planetary comparison study, image scales and actual sizes of features becomes necessary. If the exact size of a feature is not known, relative or comparative sizes of features within the same image can be described. In this lesson we will focus on relative sizes. Useful descriptors: larger than, longer than, smaller than, shorter than, narrow, wide, thick, thin, tall, short, etc.

National Aeronautics and Space Administration 2. Shape: Features can be described in terms of geometric shape. Useful descriptors: roundish, oblong, square, etc. 3. Texture: Features can be described as having a certain texture. Useful descriptors: smooth, rough, jagged, scalloped, smeared, etc. 4. Position / orientation: Features can be described in terms of their location relative to other features in an image. Useful descriptors: on top of, next to, below, under, slanted, parallel, perpendicular, etc. In this lab activity, you’ll be observing features formed by four major processes that shape the surfaces of solid objects in the solar system: wind ( aeolian processes), water ( fluvial processes), volcanic activity, and impacts . Aeolian processes: features created by or associated with the effects of wind. A planetary body needs to have an atmosphere in order to have aeolian processes. • Sand dune: a mound of sand formed by windblown sand sized particles. There are different sand dune ‐ types or shapes such as barchan (crescent-shaped), longitudinal, and star. • Wind streak : a feature formed when wind blows sand or dust sized particles off the surface (erosional) or ‐ onto the surface (depositional). • Yardang: a sharp ridge or multiple ridges oriented in the same direction formed by sand sized particles ‐ eroding exposed rock. Fluvial processes: features created by or associated with flowing water. A planetary body needs to have a certain balance between atmospheric pressure and temperature in order to have water flow on the surface. • Channel: a feature often created by the flow of water. Can vary in size and shape depending on local geology and steepness of topography. In flatter areas they meander into a snake like shape. Can include ‐ the following features: smooth margins, meanders, oxbow lakes (created when a meander is cut off and forms a U shaped body of water), streamlined islands, levees, bars, and banks. ‐ • Valley / drainage network: a set of channels formed by water draining downslope creating a network of small channels or tributaries that merge to form progressively larger channels. These features most often have a branch-like appearance. • Delta: a feature formed by the deposition of sediment that builds up where the mouth of a river flows into another body of water, such as a lake or sea. Volcanic processes: features created by or associated with volcanic activity. A planetary body needs to have a hot interior in order to have active volcanic processes. • Volcano: a raised structure that includes an opening in the crust of a planet where hot molten rock (magma) and gases escape from below the surface. • Central vent or caldera: a circular depression generally at the top of a volcano where magma and gas escape to the surface. These terms are closely related. When a magma chamber is empty enough for the central vent to collapse it is referred to as a caldera. May be oblong in shape. • Volcanic deposits (lava flows, ash flows): as hot magma reaches the surface and flows out onto the surface, it is called a lava flow. Lava flows have jagged margins. Ash flows or plumes come from more explosive eruptions and include tephra (ash, cinders, or volcanic bombs) and gas released into the atmosphere and/or on the surface.

National Aeronautics and Space Administration Impact processes – features created by or associated with a meteorite striking the surface Identification criteria Impact crater Circular feature that sometimes has a raised rim and a smooth, flat floor Flat, roundish feature that looks eroded and is sometimes filled in or outlined by water Other: Fluvial processes – features created by or associated with the effects of water Identification criteria Channel Drainage network Delta Feature has a dendritic pattern similar to the vein-like pattern in a leaf Long, extended feature that curves or meanders through an area; sometimes has two or three smaller channels connected to it Long, winding feature that sometimes contains features such as U- shaped oxbow lakes, meander scars, or teardrop-shaped island(s) Has a fan-like or triangular shape Sometimes looks like a triangle or bird’s foot where sediment is built up and deposited Numerous small channels or tributaries that feed into larger channels or valley Other: Volcanic processes – features created by or associated with volcanic activity Identification criteria Volcano Central vent / caldera Lava flow Looks similar to an impact crater and is circular in shape An entire structure that includes a circular opening at the top and has flanks or sides An entire structure that may look raised and have a cone or done or steeple-like shape Channel-like flow or finger-y appearance with uneven edges Single or multiple circular depressions at the center or top of volcano Flow-like material that appears darker or lighter than the surrounding surface Other:

National Aeronautics and Space Administration Recognizing and Identifying Features on Earth The identification criteria you just developed should help you recognize these different geologic features in other images with confidence. You must use those criteria to support your identification of these features. Feel free to refine or add to your criteria as you continue with this activity. In order to help reinforce and review your feature recognition skills you will observe the Earth Images set of images. In the table below you will: 1. List identification criteria for the main feature shown in the image (there may be others, as well). 2. Based on your listed criteria, name the main geologic feature that best matches what you observe. 3. Name the main geologic process that helped form that feature. 4. Discuss your answers with your team members and answer the questions. As you discuss your answers, you may experience how scientists (both professionals and students) do not always agree! Scientific debate and using evidence to back up interpretations are key elements of science. Be open to changing your original identification of a feature if you can be convinced based on evidence presented by your peers. It is not all about what answer is right or wrong. More importantly, it is about evidence that supports your interpretation. Not all scientists agree, which is an important aspect of how science progresses. Fill out the table below as you make observations of the images provided in the Earth Images document. Imag e # Identification Criteria (list specific criteria from your identification criteria tables) Main geological feature Main geologic process (aeolian, impact, fluvial, volcanic) 1 2 3 4 5 6

National Aeronautics and Space Administration 2. Which were the easiest features to recognize? Why? 3. Which were the most difficult features to recognize? Why? 4. As a team, determine how many of the 16 Earth feature images show each of the geologic processes. Note: some images may have more than one process . If you have three images that have volcanoes and one of them also shows impacts, you would mark down three volcanoes and one impact in the table below (i.e., any image that has a crater in it (that isn’t a caldera) should be included in your impact count). Aeolian Impact Fluvial Volcanic Recognizing and Identifying Features on Mars You have reviewed, reinforced, and refined your identification criteria for geologic features found on Earth. It is essential to use those criteria as you observe other images of Earth but also as you observe images from other planetary bodies. For this part of the activity, you will, just as planetary scientists do, use Earth for planetary comparisons. As you make observations of images from Mars, think about which images are most or least like Earth. By identifying geologic features, you will better understand the processes that may have helped shape the surface of Mars. It will also help you better understand its geologic history. Use your identification criteria as you identify features, but as available, you are encouraged to also use other resources such as books, or the internet. These resources can increase your knowledge and help support the identification of features and processes. You will be looking at the Mars Images document for this portion of the activity. The images were taken by remote sensing instruments on different spacecraft sent to study this rocky world. As you make observations of these images, you will notice that some features may match your identification criteria perfectly, while others may not. This may cause the level of confidence of the feature you identified to be high or low. The higher the level of confidence, the more strongly you, or any scientist, can debate and defend your interpretation of the features and processes shown in the images. Being able to defend your identification or discuss your uncertainty are both extremely valuable skills. Use the first row of the table below as an example as you make observations of each image: 1. Individually, list identification criteria for the main feature shown in the image. There may be multiple features in a given image. 2. List characteristics that do not match your identification criteria or observations that may cause your

National Aeronautics and Space Administration level of confidence of the identified feature to be lowered, if present. 3. Based on your listed criteria, name the main geologic feature that best matches. 4. Name the main geologic process that helped form that feature: aeolian, impact, fluvial, or volcanic. 5. List your level of confidence from 1 to 3 of the identified feature (and process): 1 = not confident, 2 = somewhat confident, 3 = very confident. 6. Compare your answers with your teammates’ answers and discuss any differences. 7. Answer the questions. Imag e # Identification Criteria (list specific criteria from your identification criteria tables) Characteristics that DO NOT match (if present) Main geologica l feature Main geologic process Level of confidenc e X Long, winding feature that looks to meander, contains u-shaped oxbow shapes Not sure if feature is raised or carved into surface Channel Fluvial 2-2.5 (pretty sure this is a channel) 1 2 3 4 5 6 7 8 Imag Identification Criteria Characteristics that DO Main Main Level of

National Aeronautics and Space Administration features were formed? How do you know? 9. Was it easier, more difficult, or about the same difficulty level to identify features on Mars than on the Earth? Why? 10. Comparing the Mars images to the images of Earth, what were differences you noticed? 11. Which images (up to three) of Mars most resemble the surface of the Earth? What about those images reminds you of Earth? 12. As a team, discuss the locations in the Mars images as possible landing sites for future missions. Which of the locations in the images of Mars would you like to send a rover to explore (you can pick up to three locations, but determine which would be your first choice and give the image number)? Why would that (those) location(s) be more valuable to explore than the others? 13. How many of the 16 Mars feature images show each of the geologic processes. Note: some images may

National Aeronautics and Space Administration have more than one process . If you have three images that have volcanoes and one of them also shows impacts, you would mark down three volcanoes and one impact in the table below (i.e., any image that has a crater in it (that isn’t a caldera) should be included in your impact count). Aeolian Impact Fluvial Volcanic 14. Using your data from the previous question and your data from the previous Earth section, graph your results in a bar graph below. Right click on the graph and select Edit Data in Excel and enter your data for Earth and Mars in the Chart in Microsoft Word Excel file. Aeolian Impact Fluvial Volcanic 0 2 4 6 8 10 12 Surface Features on Earth and Mars Earth Mars Number of images containing feature 15. Which feature(s) were most prevalent in the images of Earth? 16. Which feature(s) were least prevalent in the images of Earth? 17. Which feature(s) were most prevalent in the images of Mars? 18. Which feature(s) were least prevalent in the images of Mars? 19. Why do you think there are differences between the most and least prevalent features on the surfaces