Crater Floor Dune Field

One Image of the Day topic was the north polar sand sea and isolated dune fields at lower latitudes. Sand seas on Earth are often called 'ergs', an Arabic name for dune field. A sand sea differs from a dune field in two ways: 1) a sand sea has a large regional extent, and 2) the individual dunes are large in size and complex in form. This image shows a small dune field inside an unnamed crater south of Nili Fossae.