It was not all that long ago that a “map” of our moon, of Mars, of a large asteroid such as Vesta, of Titan, or of any hard-surfaced object in our solar system would have some very general outlines, some very large features identified, and then the extraterrestrial equivalent of the warning on Earth maps of yore that beyond a certain point “there be dragons.” Constructing a map of the topography and geology of a distant surface requires deep understanding and data and lot of hard work.
Yet such an in-depth mapping is underway and has already resulted in detailed surface rendering of Mars, of Jupiter’s moons Ganymede and Io, and of our moon. And now, using both Apollo-era data for the moon and measurements from the Japanese lunar orbiter and currently flying American orbiter, the U.S. Geological Survey, in partnership with NASA and the Lunar and Planetary Institute, has produced a rendering of our moon that moves extraterrestrial mapping significantly further.
It unifies all the data collected using a variety of techniques and produces a map with well-defined geological units, with in-laid topography (on digital versions,) and with a guide of sorts for moon watchers on Earth. The red sections in the map above are the basalt lava flows that have the fewest craters from asteroid hits and so are the youngest surfaces. They are also the darker sections of the moon that we see when we look into the night sky at a full moon.
The maps are not at a detail to allow NASA mission planners to assess a landing site, but they do tell what the geological environs are going to be and so are a guide to what might be found.
The chief purpose of the map — in which 5 kilometers of distance are represented by 1 millimeter on the map — is to summarize the current state of lunar geologic knowledge.… Read more