Giordano Bruno Whorl

Impact melt forms a swirled feature in Giordano Bruno crater, as seen in this image from NASA's Lunar Reconnaissance Orbiter. The area shown is a little more than half a mile (about 1 kilometer) across. This spiral-shaped feature may have formed due to shear stress created when molten impact melt flowed at different speeds (probably caused by drag from the pool floor or an obstacle within the pool). Learn more.