Whale level

Whale planes are large craters on the moon , the mostly flat inner surface of which is surrounded by a round wall. They have a diameter of between about 60 and 300 km.

The floor of the whale plain can be covered by small craters, mounds or grooves . It is usually a little deeper than the surrounding terrain and adapts to the curvature of the lunar sphere, which results in attractive lighting effects on the steps of the terrain and on the edge of the crater when the sun is low .

The mighty wall at these large craters is between 1 and 5 km high, often richly structured and criss-crossed by furrows or fissures . Small craters and ground slides can also interrupt the wall. The ratio of wall height to diameter is on average 1:40 to 1:80. An astronaut standing inside could therefore often no longer see the wall (the moon is much smaller than the earth and its surface is four times more curved). The inner walls are sometimes stepped and steeper than the outer slopes. The central mountain, which is common in smaller craters, does not exist in whale plains because the dynamics of the meteorite impact are larger.

Significant whale plains are

• Clavius (approx. 200 km, in the southern highlands)
• Ptolemy (approx. 150 km, near the center of the moon)
• Posidonius (100 km, northwest of the center of the moon)
• Schickard (approx. 200 km, near the southwestern edge) and
• Bailly - with 300 km the largest whale plain; directly on the south-western edge of the moon, so only very distorted visible.