Scientists from the Hong Kong Polytechnic University have devised ways to precisely map the moon by using data collected from various space missions.
Their work has improved understanding of the topography and core substance of the moon, and will be useful in determining where to land in future missions.
Helped by mainland and overseas research centres, they created a digital elevation model of the moon by combining laser altimeter data obtained from the Chang'e I mission and others, including Japan's SELENE and America's Clementine missions.
Chang'e I was a Chinese lunar- orbiting spacecraft that was launched in 2007. Chen Yong-qi, emeritus professor of the university's land surveying and geo-informatics department, led the team. Chen is also on the expert committee of the mainland's Lunar Exploration Programme.
'Although research about the moon began a long time ago, we still know very little about it - like how thick exactly its crust is, what's inside, and the topography and weight of it,' Chen said.
Researchers found that the average thickness of the moon's crust was about 40 kilometres on the side near the earth, and about 50 kilometres on the other side. They have come up with a more accurate gauge of the moon's shape. It was 'like an egg', researchers said. The small end of the 'egg' points towards earth. This position causes the moon to keep the same face towards earth at all times.