What external event can initiate the large-scale gravitational collapse of a molecular cloud region?

Answer

Shockwave from a nearby supernova explosion

The initial contraction usually requires an external catalyst, such as a shockwave propagating outward from a supernova, to compress a section of the cloud past a critical density.

What external event can initiate the large-scale gravitational collapse of a molecular cloud region?

#Videos

Birth of a star - from nebula to main sequence - YouTube

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