Lunar exploration has taken on enormous importance in planetary research in recent years. The Moon, with its ancient surface, largely over four billion years old, is to some extent, a window to the early days of the Solar System. On Earth, the dynamic processes in the crust wiped out nearly all traces of this a time long ago.
The early history of the Earth could be deciphered partially by analysis of the lunar rock samples that astronauts brought back to Earth. Most likely, the mass of the Moon contributed to stabilising Earth's axis of rotation and could have influenced the development of life on Earth considerably.
This image, acquired by NASA's Galileo spacecraft in December 1992, shows a view of the North Pole of the Moon, which lies roughly in the centre of the terminator (boundary between day and night), at the upper right. The illuminated areas show the northern hemisphere of the near-side of the Moon with the dark regions of the volcanic plains, or mare – which are visible from Earth with the naked eye – and the bright, pristine lunar highland crust.