What are the primary chemical constituents of a nebula by mass?

Answer

Roughly 70% hydrogen and 28% helium

Molecular clouds, the building blocks of stars, are primarily composed of approximately 70% hydrogen and 28% helium by mass, with the remainder being heavier elements from previous stellar generations.

What are the primary chemical constituents of a nebula by mass?

#Videos

What Causes A Nebula To Collapse? - Physics Frontier - YouTube

forcegravityprotostarnebulacollapse