Question of the Day

Question to answer... How are stars formed and what evidence is there of their formation?

The study of star formation is ongoing; however, astronomers do have a theory with supporting evidence. When the Big Bang occurred 14 billion years ago it expelled hydrogen and helium. The gas molecules had mass, ergo they had gravity. Dense gas clusters began to collapse surrounding gases upon itself and grow in mass, eventually the resulting increase in temperature was enough to start nuclear fusion. By fusing hydrogen, heavier elements, like iron, started to enter our universe. Nuclear fusion, creation of heavier elements, and gravity all contributed to the formation of the earliest stars. On a side note, when stars use up all their "fuel" in their cores they slowly collapse upon themselves. Consequently, hotter, denser cores are formed and the outer layers of the star are pushed away, thereby cooling the outer layer. What happens next depends on the star's mass; however,  should the star happen to expel the rest of its matter, it shall be recycled by the universe and make new stars.

"Pillars of Creation"

-Observational Evidence-
+The Rossi X-Ray Timing Explorer has captured telltale X-Ray emissions of gas swirling just a few miles from the surface of a neutron star.
+  The Orion Nebula has young stars that are shaping the nebula to the pillars of dense gas that may be the homes of budding stars. The Eagle and Lagoon nebulae also show this.
+ Binary systems and planets hint that the same condensing gases made everything. Less massive formations became the smaller celestial objects that orbit the larger masses in out universe.

-Physics and Mathematical Evidence-
+ White Dwarfs do not collapse do to the pressure of fast-moving electrons, as dictated by quantum physics.
+ Gravity, nuclear fusion, solar wind, and the  Hertzsprung-Russel Diagram can be explained by what we know about the interaction of atoms, radiation, and the radius-luminosity-temperature relationship.
The Comments Section has the sources.