Mercury - 2

What is the source of the radiating streaks in the image on the left? It is the impact crater Hokusai, seen at the top of the frame, named for Japanese artist Katsushika Hokusai. Its impressive ray system extends for as far as 1000km. Such rays are formed when an impact excavates material from beneath the surface and explodes it outward from the crater. Rays such as these fade over time as they are exposed to the harsh space environment. Hence, craters with bright rays are thought to be relatively young.