A fter its formation, the moon may have been the scene of such immense volcanic activity that its entire crust melted several times and was completely churned through. At that time, the moon ...

At 4,000 miles long and 30–40 miles wide, the East African Rift (EAR) system is one of the geologic wonders of the world.

These crustal collisions occur gradually over millions of years, yet have a profound impact in reshaping the Earth's surface.