Sir

Your Editorial “Brave blue world” (Nature 445, 459; doi:10.1038/445459a 2007) correctly points out that Antarctic science “has been central to the great project of understanding the changes that humans are inflicting upon the Earth”. You go on to say that “the only input that lunar activity will provide for the study of Earth is the iconic and inspiring sight of a blue planet in a black sky over a grey desert”.

But when Antarctic exploration began, the concept of global warming that had been introduced by G. S. Callendar1 in 1938 was only beginning to be taken seriously2. Studies in the 1950s focused mainly on ocean turnover of carbon dioxide. That an Antarctic base would reveal humanity's contribution to climate change with such clarity was not a driver for building a base, and ultimately many findings were serendipitous — we certainly were not looking for an ozone hole, for example.

If the only goal of an Antarctic base was to gather atmospheric data, it would have been easier and much cheaper to use aircraft rather than build a base. Similarly, if the only goal of a Moon base is to observe Earth, it is cheaper and easier to use satellites. This misses the main point of establishing a distant outpost. In general, if one picks a single function of the outpost, it is possible to find a cheaper and easier way to perform that particular function. But the multiple goals of a broad scientific expedition help each other succeed in many ways. Antarctic discoveries were made because we established long-term monitoring in a scientifically interesting place with no guarantees of the ultimate importance of the science.

Similarly, the Moon is a scientifically interesting place to explore and, although there are no guarantees, long-term monitoring of the entire Earth, as visible from the Moon, is a pretty good bet to provide important discoveries that we are unable to anticipate at present. Just as the synergies of exploration, oceanic, atmospheric, geological, biological and meteoritic investigations combined to yield rich results from Antarctica, we will one day be amazed by the wealth of knowledge gained from the Moon.