What is the primary function of dust grains in the formation of molecular hydrogen ($ ext{H}_2$) within a nebula?

Answer

Dust grains provide the necessary surface area for hydrogen atoms to collide and stick.

Molecular hydrogen ($ ext{H}_2$) does not form efficiently in the gas phase; dust grains offer the surfaces required for hydrogen atoms to combine into molecules.

What is the primary function of dust grains in the formation of molecular hydrogen ($	ext{H}_2$) within a nebula?
SpaceastronomynebulaGases