A closer look at Mars reveals new type of impact crater

Lessons from underground nuclear tests and explosive volcanoes may hold the answer to how a category of unusual impact craters formed on Mars. The craters feature a thin-layered outer deposit that extends well beyond the typical range of ejecta, said Nadine Barlow, professor of physics and astronomy at Northern Arizona University.

Ancient impact crater found in Greenland

An international team of scientists has identified an ancient 100 kilometer-wide crater near the Maniitsoq region of West Greenland.