And how much longer will it continue to shine? For an idea of the Sun’s life expectancy, astronomers look to clusters of stars, such as one named Messier 67, which is about the same age as our Sun. By simulating the life cycles of these stars on a computer, astronomers have ascertained how long stars live. They predict that the Sun will be able to fuse hydrogen into helium in its core at about the same rate for another 5 billion years. (What a relief!) If the Sun were a car, the gas tank would now be half full.