GENERAL KNOWLEDGE

Detailed explanation-1: -Stars are born within the clouds of dust and scattered throughout most galaxies. A familiar example of such as a dust cloud is the Orion Nebula. Turbulence deep within these clouds gives rise to knots with sufficient mass that the gas and dust can begin to collapse under its own gravitational attraction.

Detailed explanation-2: -Most stars are born inside great clouds of gas and dust called nebulas. The process begins when a nebula starts to shrink, then divides into smaller, swirling clumps. Each clump becomes ball-shaped, and as it continues to shrink the material in it gets hotter and hotter.

Detailed explanation-3: -CO and H2 are the most common molecules in interstellar gas clouds. The deep cold also causes the gas to clump to high densities. When the density reaches a certain point, stars form. Since the regions are dense, they are opaque to visible light and are known as dark nebula.