The moon does not yield her secrets easily.
Although Earth's airless satellite was the first planetary object to be explored by spacecraft and the only body ever visited by astronauts, scientists still have many unanswered questions about its history, composition and internal structure. In recent years, researchers have called for renewed exploration of the moon; the European Space Agency and Japan are planning to send probes into lunar orbit, and NASA is considering landing an unmanned spacecraft on the moon's far side. By studying the moon, these missions may also illuminate the history of all the rocky planets in the inner solar system: Mercury, Venus, Mars and especially Earth. Because the moon's surface has remained relatively unchanged for the past three billion years, it may hold the key to understanding how the inner planets formed and evolved.
This article was originally published with the title The New Moon.