The central molecular zone ( CMZ ) hosts some of the most massive and dense molecular clouds and star clusters in the Galaxy , offering an important window into star formation under extreme conditions .
Star formation in this extreme environment may be closely linked to the 3-D distribution and orbital dynamics of the gas .
Here I discuss how our new , accurate description of the \ { l,b,v\ } structure of the CMZ is helping to constrain its 3-D geometry .
I also present the discovery of a highly-regular , corrugated velocity field located just upstream from the dust ridge molecular clouds ( which include G0.253+0.016 and Sgr B2 ) .
The extremes in this velocity field correlate with a series of massive ( \sim 10 ^ { 4 } M _ { \odot } ) cloud condensations .
The corrugation wavelength ( \sim 23 pc ) and cloud separation ( \sim 8 pc ) closely agree with the predicted Toomre ( \sim 17 pc ) and Jeans ( \sim 6 pc ) lengths , respectively .
I conclude that gravitational instabilities are driving the formation of molecular clouds within the Galactic Centre gas stream .
Furthermore , I suggest that these seeds are the historical analogues of the dust ridge molecular clouds – possible progenitors of some of the most massive and dense molecular clouds in the Galaxy .
If our current best understanding for the 3-D geometry of this system is confirmed , these clouds may pinpoint the beginning of an evolutionary sequence that can be followed , in time , from cloud condensation to star formation .