| Some of the images in the Spuzzled game seem to be of some strange other world. Surely they are not pictures of our own Earth! The view of Earth from space is very different from the view at ground level. We can really see the big picture. We can see mountains and valleys, rivers, forests, lakes, farmlands, and shorelines. We can see volcanoes erupting, wild fires burning, and ice sheets forming and melting. |
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High above us, the Landsat satellites gather information about Earth. They send the data to ground stations around the world. The Landsat Project began in the early 1970s. Landsat 7 was launched April 15, 1999, and is the newest Landsat. Landsat 5 is also still operating. |
| Landsat 7 orbits 705 kilometers (438 miles) up. Its orbit takes it up near the North Pole and down near the South Pole, so Earth turns underneath Landsat. It takes just 99 minutes to orbit Earth once and 16 days to take data of all the land on Earth. Then it starts over taking data of the same scenes, but 16 days later. |
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| Landsat 7 has a very special Earth-observing instrument called the Enhanced Thematic Mapper Plus (ETM+). It can "see" features on the ground that are as small as 15 meters (49 feet) across. So, it couldn't see a car, but it could probably see a house. The ETM+ can also see more different colors of light than human eyes can see. That is why the Landsat images seem so colorful. They have been color enhanced to help our human eyes see all the details and colors the Landsat instrument sees. |
| The system for handling Landsat data divides the world's landmass into 57,784 scenes. Each scene is 185 kilometers (115 miles) wide by 170 kilometers (106 miles) long. The amount of data the ETM+ produces for just one scene would fill nearly 15 sets of encyclopedias at 29 volumes per set! So you can imagine that storing and keeping track of all this data is a big job. |
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| Scientists from all over the world can get Landsat data for specific locations and times to study. The images and other data from the Landsat satellite are used to monitor changes in Earth's climate and environment. |
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