Depending on its mass, it can take millions to trillions of years for a star to evolve from a main-sequence star to a red giant.
Despite this astronomical length of time, astronomers are confident in their models of stellar evolution. Which of the following statements best describe why astronomers firmly believe that their models of stellar evolution are correct?
Because Astronomers have well-tested theoretical models that explain how a star evolves over the course of its life as well as well-tested theoretical models that explain how a star evolves over the course of its life.
