. . . of Mercury. NASA’s MESSENGER probe photographed Mercury’s hidden hemisphere yesterday as it paid the first visit to the innermost, smallest (now that Pluto’s been demoted) planet. Here’s a whole new view of a nearby neighbor, cosmically speaking. Yeah, it kind of looks like the part of Mercury we’d already seen, but that’s not the point. MESSENGER has a couple of more loops around the inner solar system to make before it is placed in orbit around Mercury, so we’ll be getting plenty more pictures when that comes to pass. Nice to have a new planet to ponder as the Mars Rovers go into hibernation for the winter. Meanwhile, somewhere near Saturn, Cassini also mapped Titan’s South Pole for the first time. I’ve said it before and I’ll probably say it again, but these are glory days for planetary exploration! Nerd out!