Finding Impact Craters with Landsat
| Image above: Middle school students study impact craters in this classroom activity. Credit: NASA
The moon is famous for its various craters, large and small, many of which can be seen with the naked eye. But did you know that craters also dot the surfaces of planets throughout our solar system, including Earth?
Meteorites - pieces of asteroids or comets - have been pelting Earth ever since its formation. These powerful collisions create what are known as "impact craters," and can affect the land, atmosphere, water and living things for millions of years.
Image to right: Is this an impact crater? Answer can be found at the end of this article. Credit: NASA
Impact events have formed major ore deposits, generated large crustal disturbances, produced huge volumes of igneous rock, and may have played a key role in the formation of ocean basins and the oceans themselves. Not to mention the extinction of dinosaurs was probably triggered when an asteroid crashed into Earth 65 million years ago.
"Finding Impact Craters With Landsat" is a NASA classroom activity that helps middle school students understand how impact craters are identified using satellite images. The effects of impact events on the Earth's geology, biology and chemistry are also investigated.
The module consists of a series of worksheets and satellite images, all of which are available online. Students begin by expressing what they think the effects might be of the rapid release of kinetic energy associated with an extraterrestrial object hitting the Earth, before reading about the actual effects of an impact event.
Image to left: El'gygytgyn Crater filled with water in Northeastern Siberia. Credit: NASA
Then, in small groups, students study images from NASA's Landsat 7 and other satellites that show possible evidence of impact events. Finding this evidence requires careful interpretation of the images, as much of it has been eroded away by wind and water, concealed by various other geologic processes, or covered up by oceans and vegetation.
Finally, to demonstrate their understanding of how impact events shape the Earth, students come up with a series of questions intended to guide a field expedition trying to determine whether or not a given landform is an impact crater.
The entire module, including background material, lesson plan, a student learning assessment rubric and related resources, is available at:
No, it's an aerial view of Mt. St. Helens in Washington