“…Then H 2 forms (more easily on rough grain surfaces, Cuppen & Herbst 2005), and where there is enough of it, you get giant molecular clouds (Stark & Lee 2005), dark clouds (catalogued by Dobashi et al 2005), and Bok globules, which rotate, say Gyulbudaghian & May (2004) with periods near 10 7 years. This seems long, given that characteristic time scales for formation, destruction, and conversion to stars of GMCs are also a few times 10 6 to 1-2 × 10 7 years (Bergin et al 2004, Monaco 2004, Tassis & Mouschovias 2004, Goldsmith & Li 2005.…”