: How do scientists determine the age of the stars, or just their remaining life time?
In: Chemistry
[Spectroscopy](https://en.wikipedia.org/wiki/Spectroscopy). The light emitted by the stars, the photons, interact with the material (hydrogen, helium, etc.) and are absorbed / re-created by it. The various colors in the light (wavelengths, bands) reveal info about the elements in the star.
And they also rely on understanding of the [nuclear processes](https://en.wikipedia.org/wiki/Stellar_nucleosynthesis) going on in stars. In order for carbon to be created / if we’re seeing carbon in the spectra, then this much pressure and temperature must be present, and you only get that in a star that’s this big, etc.
The stars are basically [classified](https://en.wikipedia.org/wiki/Stellar_classification) into nice little groups, kinda like different species of animals. You look at the colors and general shape and you can tell it’s a tiger. And you know from years of studies in the past, what a tiger is and what a tiger does.
Latest Answers