Researchers analyzing satellite images of the Sahara have discovered the region’s largest impact crater, a 31-kilometer-wide feature located in remote southwestern Egypt.
The crater’s heavily eroded rim (marked by the white dashes) rises about 230 meters above the surrounding terrain, says Eman Ghoneim, a physical geographer at Boston University. The age of the crater is unknown, but the feature must be younger than 100 million years, the age of the underlying sandstone, Ghoneim and her colleague Farouk El-Baz announced last week.