Visual Timeline of the Universe

Gravity acts on individual particles to form collections that attract still more particles. Under the right conditions, gravity can overcome the disruptive forces of heat and turbulence to create spheres of gas that are hot enough and dense enough at their centers so that hydrogen can fuse into helium -- creating a star. But this new star will probably not yet be apparent in visible light. The young star is surrounded by a dense, opaque shroud of dust. As the star heats the dust, the star becomes detectable by infrared telescopes as a "hot spot" within a large, dense molecular cloud. Winds from the star will eventually blow away residual gas and dust and the star will become visible in optical telescopes.