How old is the Sun

The Sun is approximately 4 1/2 billion years old. Humans have only existed for a portion of this period. If you consider 4.5 billion years to be the length of a 12 inch ruler (or 30.5 cm ruler), the period humans have lived would be less than the width of the lines defining the inches.

For the next 5 billion years, the Sun will stay essentially unchanged. It will then exhaust the hydrogen it is now "burning" and start a new phase of existence. During this phase, the Sun will start "burning" helium and will grow to nearly 100 times its current size, becoming a red giant. When it runs out of helium, it will shatter into a much smaller object known as a white dwarf.