ocr: 9 917 MARS AND EARTH: A COMPARATIVE HISTORY The case of the Moon THE SEARCA FOR The Moon's history is very different from the Earth's. Scientists say the major reason is the. Moon's low mass. The Moon is, in fact, 81 times lighter than the Earth. Similarly, the heat generated within the Moon by radio activity was much lower, and the Moon's weak gravitational field could not hold an atmosphere. Unable to retain any water vapor, the Moon never evolved oceans or seas. The problem of Mars What about the history of the planet Mars, whose mass is less than Earth's but greater than the Moon's? The ne ...
