The *big* picture (part 1)

A long overdue, news of astronomy post.

MercuryLet's begin with reports from MESSENGER -- MErcury Surface, Space ENvironment, GEochemistry and Ranging. (How long did someone labor to come up with that acronym -- still to cheat, repeatedly?) This mission learned a lot about our solar system's innermost planet. Recursively, perhaps, I consider findings about that world's innermost parts the most fascinating:

Mercury's core is huge for the planet's size, about 85% of the planetary radius, even lar...