Credit: NASA/JPL/UNIV. ARIZONA

The crater Stickney, on Mars's moon Phobos, is shown beautifully in this new picture acquired by the HiRISE high-resolution imaging instrument aboard the Mars Reconnaissance Orbiter.

The bluish (false) colour in this image could represent material younger than the rest of the moon's surface. Stickney, named after the wife of Phobos's discoverer, was probably formed in a giant impact that nearly shattered the moon. The crater is 9 kilometres across, the moon itself just 22 kilometres.

The long grooves that radiate out from Stickney may be left over from the impact that created it, or could have been formed by debris from the impact of another body on Mars itself, which is less than 6,000 kilometres from the moon.