Mapping Rocks From Space

The Himalayan mountain range is known for its majestic beauty and towering heights, but the very features that make it famous can keep scientists from understanding its details. To make sense of the history of this mountain range, geologists need to see the rocks that they are made of. However, this can be difficult because of the sheer heights and inaccessibility of parts of the range. To solve this, we got a bird’s eye view of these mountains—from space! Using data from the ASTER instrument aboard NASA’s Terra satellite, we looked at the spectral signature of the rocks that make up the mountains. A spectral signature is almost like a fingerprint. We used this information to make a geologic map of the northwestern Himalaya, which helped us to piece together part of the history of these mighty mountains.