When I consider thy heavens, the work of thy fingers, the moon and the stars, which thou hast ordained; Psalm 8:3
"Many astronomy articles have a bad habit of assuming star formation without demonstrating or explaining it.
In Hollywood, A Star Is Born by intelligent design. Out in the near vacuum of space, however, it’s complicated. The laws of physics don’t cooperate. Gravity may begin condensing gas and dust toward a hopeful career in the lights, but then those darn laws of heat and pressure take over, pushing the gas back out. Something has to give the gas an extra push to make it over the pressure barrier. Maybe a supernova explosion could do it. That appeal, however, is likely to get philosophers of science smirking. They will ask, “If that is your answer, where did the first stars come from, before there were no supernovas?” [For purists, that’s supernovae.] “You can’t require stars to make stars.”One might think Phys.org’s article “Forming stars in the early universe” would talk about forming stars. Let’s search on “form” in the article.
- The first stars appeared about
one hundred million yearsafter the big bang, and ever since then stars and star formation processes have lit up the cosmos. - When the universe was about
three billion years old, star formation activity peaked at rates about ten times above current levels. Why this happened, and whether the physical processes back then were different from those today or just more active (and why), are among the most pressing questions in astronomy. - Since stars are made from gas, the gas content of galaxies is a measure of their star formation potential and (at least in the local universe) the fraction of matter in form of gas, the “gas fraction”, is a measure of the star formation capability.
- Gas in galaxies is depleted as new stars are formed and as some of it is blown out of the system by supernovae or by winds; gas can also be added by infall from the intergalactic medium.
CEH
