What’s so hard about counting craters?

The journal Icarus published a study this month that compared lunar crater counts by eight professionals with crowdsourced counts by volunteers. The professional crater counts varied by as much as a factor of two. Two of the professionals, both planetary scientists at Washington University in St. Louis, explain why they weren’t surprised.

Two other Mars missions heating up

The Mars Reconnaissance Orbiter (above) is poised to go into orbit around Mars in March, then spend about six months aerobraking to place the spacecraft in a low circular orbit by this fall.Two Mars orbiter missions — one from NASA, the other from the European Space Agency (ESA) — will open new vistas in the exploration of Mars through the use of sophisticated ground-penetrating radars, providing international researchers with the first direct clues about the Red Planet’s subsurface structure. Roger Phillips, Ph.D., Washington University in St. Louis Professor of Earth and Planetary Sciences in Arts & Sciences, is participating in both the Mars Express (ESA) and NASA’s Mars Reconnaissance Orbiter (MRO) missions by lending his expertise in radar. Phillips says that the combination of the radars on the two missions will provide important and unique data sets that will directly map the structure of the upper portions of the interior of Mars. More…