I’ve enjoyed seeing the pictures of Mercury from the MESSENGER flyby. (If you haven’t already seen it, you should definitely check out pictures of the spider.) So far, the news accounts don’t seem to do a very good job explaining the scientific importance of the results. Here’s an article that gives quite a bit more detail about the sorts of questions that can be addressed with these data.
At this stage, not surprisingly, the data have raised a lot more questions than they’ve answered. It’ll be a lot of fun to see what comes out of the rest of the mission.
By the way, here’s a nice introductory physics puzzle: Why is it hard to get to Mercury? Obviously, it takes a lot of energy to get to the outer planets, since you have to go “uphill” against the Sun’s gravity. But Mercury’s dowhill from us, so it ought to be easy to get there.