[[Uniformitarianism|Uniformitarians]] commonly estimate that the Sun is about 4.5 billion years old, has consumed about half its nuclear fuel ([[hydrogen]]), and will begin to die within about 5 billion years.<ref name=thinkquest>"[http://library.thinkquest.org/29394/sun.htm Entry for the Sun]." ''Gateway to the Future,'' <http://library.thinkquest.org/>. Accessed March 5, 2008.</ref> | [[Uniformitarianism|Uniformitarians]] commonly estimate that the Sun is about 4.5 billion years old, has consumed about half its nuclear fuel ([[hydrogen]]), and will begin to die within about 5 billion years.<ref name=thinkquest>"[http://library.thinkquest.org/29394/sun.htm Entry for the Sun]." ''Gateway to the Future,'' <http://library.thinkquest.org/>. Accessed March 5, 2008.</ref> |