What happened to the debris from the collision that formed the Caloris Basin on Mercury? Why didn’t it form a moon?
Fabian Marson
Wyndham Vale, Australia
Mercury’s Caloris Basin is about 950 miles (1,525 kilometers) across. For comparison, the state of Texas is 773 miles (1,244 km) wide. The Moon has a similarly sized impact crater, Mare Orientale.
Researchers estimate that the collision that created the Caloris Basin occurred some 3.8 billion years ago, when a small body about