A little while back, I blogged about plans to let the SMART-1 probe impact the Moon. My friend Emily Lakdawalla interviewed Bernard Foing, the Project Scientist for SMART-1, about their plans, and she clears up some of the questions I wasn't able to answer. The impact will occur on or about September 2-3. The uncertainty is due to -- get this -- the fact that the angle of impact is incredibly small, about a degree, so the probe will be skimming the surface of the Moon for the last few hours. If a hill rears up, smack! Since we don't know the topography of Moon very accurately, they're not sure exactly when or where it will hit. That's amazing, and makes me realize that even though the Moon is the closest of the objects in the sky, there is still a lot more to learn and to know about it.