Shameless copy from SF.'s question on Space Meta:
\usepackage{marvosym} allows you to write M_\Sun or r_\Earth to have variables annotated with celestial body symbols. It would be surely nice to have in the mark-up.
The list of planet symbols included is as follows:
\Sun \Moon \Mercury \Venus \Mars \Jupiter \Saturn \Uranus \Neptune \Pluto \Earth
Would it be much trouble to include this package in our set, so that this would work?:
$M_\Sun = 1.989e30 kg$
