Petronius latitude: 86.82°N; longitude: 322.3°E
Petronius crater (36 km (22 mi.) in diameter) is a region of permanent shadow and is also known to host radar-bright deposits.
Carolan latitude: 83.8°N; longitude: 31.7°E
Evidence from the radar, topography, shadow, and temperature datasets all support the presence of water ice in this 24 km (15mi) diameter crater, Carolan.
Center latitude: 90°N; longitude: 180°E
Scale: Prokofiev crater, the largest in this image, is approximately 110 km (68 mi.) in diameter.
Unlike Earth, which is tilted by about 23.5° on its spin axis, Mercury’s axis has a tilt of nearly zero. Therefore, near Mercury's north and south pole, the Sun is always low on the horizon. Long sunsets and sunrises are broken only by long nights. But for some impact craters near the poles, no sunlight ever directly reaches portions of the crater floor and crater walls due to the long shadows cast by the crater rim and the surrounding higher-elevation terrain. These areas of permanent shadow remain extremely cold, even on the planet closest to the Sun. Evidence from radar, topography, shadow, and temperature datasets all support the presence of water ice in Carolan crater (left image) and other permanently shadowed craters on Mercury.