If you take a universe worth of hydrogen and helium, and let it stew for about 13 billion years, you get us. We are the descendants of the primeval elements. We are the cast-off dust of the first stars, and many generations of stars after that. So our search for the first stars of the cosmos is a search for our own history. While we haven’t captured the light of those first stars, some of their direct children may be in our own galaxy.
If you take a universe worth of hydrogen and helium, and let it stew for about 13 billion years, you get us. We are the descendants of the primeval elements. We are the cast-off dust of the first stars, and many generations of stars after that. So our search for the first stars of the cosmos is a search for our own history. While we haven’t captured the light of those first stars, some of their direct children may be in our own galaxy.
The first stars were massive. Without any heavier elements to weigh them down, they needed to be about 300 times that of our sun in order to trigger nuclear fusion in their core. Because of their size, they went through their fusion cycles rather quickly and lived very short lives.
But the supernova explosions signaling their deaths scattered heavier elements such as carbon and iron from which new stars formed. Large second-generation stars also died as supernovae and scattered even more heavy elements. As a result, each generation of stars contained more and more of these elements. In astronomy lingo, we say each generation has a higher metallicity.
Of course, which generation a star is in can be fuzzy.
