Free Astronomy Magazine January-February 2016

50 PLANETOLOGY and weight of the sand grains containing them, the effect would be that the study of the sandstone resulting from the trans- formation of this selected sand could lead to erroneous assessments of the role of water in its formation. In short, a more thorough understanding of the mech- anisms acting on the dunes may have im- plications in a more general assessment of the role of water on Mars. Curiosity has now, in fact, the task of understanding if the wind actually sorts the minerals, as well as how it moves individual grains of sand and what differences there are be- tween the top-most layer of sand and those underneath. The rover has already started with its wheels to loosen the soil of the first dune encountered (High Dune) and to investigate it with its instrumen- tation. Inevitably, before we have the re- sults a lot more wind will blow where Curiosity is. For now, it has only been possible to ascertain, through surveys by the Compact Reconnaissance Imaging Spectro- meter on the MRO, that the min- eralogical composition of Bagnold Dunes is not evenly distributed. Pending further specific informa- tion, we can meanwhile admire on these pages the first highly de- tailed images released by NASA of the place where the rover is cur- rently operating. C lose-up of sand grains of High Dune, not disturbed by the Curiosity rover’s activity. This shot was taken on 5 December with the Mars Hand Lens Imager (MAH- LI). The framed area is only 3.6 × 2.7 cm. [NASA/JPL- Caltech/MSSS] On the side, an exciting video that retraces the 50 years of Mars exploration and anticipates what will happen in the near future. [NASA] n