Radiogenic dating of meteorites
The absence of swirling clouds, oceans, and an atmosphere reveal the water-poor nature of the Moon.
Also seen in this photograph are the fundamental differences between the dark lava-covered maria and the lighter highlands, or terrae, which are intensely cratered.
Moreover, many of the Moon's surface features have become well known, especially since the days of Galileo, the first to study the Moon through a telescope.
Even the density and gravitational field of the Moon had been determined long before our generation.
As it turns out, the Moon is truly a whole new world, with rocks and surface features that provide a record of events that occurred during the first billion years of the solar system.
In spite of its small size and forbidding surface, the Moon has revealed secrets that pertain to the ultimate creation of our planet, Earth, and our neighbors beyond.In many ways the Moon is a geologic Rosetta stone: an airless, waterless body untouched by erosion, containing clues to events that occurred in the early years of the solar system, which have revealed some of the details regarding its origin and providing new insight about the evolution of Earth.Although they also posed new questions, the thousands of satellite photographs brought back from the Moon have permitted us to map its surface with greater accuracy than Earth could be mapped a few decades ago.We now have over 380 kg of rocks from nine places on the Moon, rocks that have been analyzed by hundreds of scientists from many different countries.Data from a variety of experiments have revealed much about the Moon's deep interior.