Same issues as with Jupiter - it was in iambic pentameter and the first 8 lines were fine but again the sestet was Wordsworthian. The split here was even worse - a logical break between 2 & 3; another between 5 & 6, leaving a last line that is almost an epigram.

The solution was similar. This time I kept the first and last line exactly the same, then reworked the rest so that the dark side of Mercury finished on line 3 instead of line two, with the starting C-D-E.

Then bulk of the original lines 3, 4 and 5 were rerouted to become the sun side, in two lines. The balance now fits the Italian sonnet style, even with that epigram, which balances the introductory line 1. 

A few further changes were made for the AllPoetry site - I keep finding better words

Mercury does in fact rotate, but one mercury day takes 2 mercury years. It's going to be a very hostile environment. Daytime temperatures up to 430°C and nighttime down to -180°C. Sounds like you need to land somewhere in the dark and dig a really big cave to use all that rock as insulation. Lead melts at about 325°C