Stories, updates, insights, and original analysis from The Planetary Society.
I've been fascinated by Mercury's hollows ever since MESSENGER discovered them. Two recent papers look at where they are found to try to figure out how they form.
Pushing back the frontier, and filling in the blank spaces on the map.
When Mariner 10 flew past Mercury, it caught an immense impact basin lying half in and half out of sunlight, which they named Caloris. Even with only half the basin visible, scientists knew it was one of the largest in the solar system. Geologists had to wait more than 25 years to see the rest of Caloris, and when they did it turned out to be even bigger than they had thought. But the fact that Caloris was only half in sunlight was fortuitous in one sense, because it meant that the spot on Mercury that was exactly opposite the area of the Caloris impact was also partially in sunlight. That spot looks weird.
This is MESSENGER's very first photo from Mercury orbit, a wide-angle view that reaches right to Mercury's south pole, exposing a very tiny sliver of territory not previously seen by spacecraft.
The United States Geological Survey has just released a new atlas of Mercury, the first to be based upon the three flybys worth of image data gathered by the MESSENGER mission.