Context : The large Coalsack dark cloud is one of the most prominent southern starless clouds , which is even visible to the naked eye .
Furthermore , it is one of the rare molecular clouds without clear signs of star formation .

Aims : We investigate the dynamical properties of the gas within the Coalsack .

Methods : The two highest extinction regions were mapped with the APEX telescope in ^ { 13 } CO ( 2–1 ) comprising a region of \sim 1 square degree .

Results : In addition to the well-known , nearby gas component around -4 km s ^ { -1 } , we identified additional molecular gas components – in particular a second extended molecular cloud at a velocity of \sim - 30 km s ^ { -1 } and an estimated distance of \sim 3.1 kpc – that dominate the column density and visual extinction distributions in the northeastern part of the Coalsack .
Although comprising \sim 2600 M _ { \odot } , the mass of this distant cloud is distributed over an extent of \sim 73 pc , much larger than typical high-mass infrared dark clouds .
Its filamentary structure is consistent with a compressible gaseous self-gravitating cylinder , and its low mass per length indicates that it may be stable against gravitational collapse .
We find barely any mid-infrared emission in archival MSX data , which is indicative of almost no star-formation activity in the near and far cloud complexes .
The nearby clouds have narrow , almost thermal velocity dispersions with median values between 0.2 and 0.4 km s ^ { -1 } , which is also consistent with low star-formation activity .
Only Tapia ’ s Globule 2 exhibits a velocity dispersion increase toward the extinction peak and peak-velocity gradients over the core , which is indicative of a state of elevated dynamical properties .

Conclusions : The Coalsack is not one single coherent structure , but consists of several cloud complexes nearby as well as at several kpc distance .
All studied clouds appear as starless low-turbulence regions that may not even collapse in the future .
Only one globule exhibits more dynamical signatures and is a good candidate for present/future star formation .