Sun: Like everything we know, the Sun, our yellow star, the biggest and main source of energy in the entire Solar System, will one day come to an end. While we don’t know exactly when, we do have good estimates and general ideas about what its next billion years will look like. But how is it even possible to infer such things?
Like many objects in the universe, we are unable to study and analyze the evolution of individual stars over time. That’s because the lifetime of these stars is much longer than the lifetime of human beings, even if we put hundreds of generations into that account.
Fortunately, the universe is a very large place and countless stars reside in it. There are hundreds of billions in our galaxy alone! This makes it possible to observe a very large number of stars at very different evolutionary stages.
You can see big stars, small stars, young stars and old stars, blue and red. These observations, supported by plausible and verifiable hypotheses (and also a dash of creativity and imagination), enable astronomers to assemble the puzzle of star history, understanding its life from birth to death.