Some of them seem to last much longer than that, or are hypothesized to. If an element has a half-life of a million years, then it probably exists in large quan

Some of them seem to last much longer than that, or are hypothesized to. If an element has a half-life of a million years, then it probably exists in large quantities throughout the universe. The solar system is a relatively closed system, though, so the elements we see around us have generally been in the solar system for its entire lifetime. So an element would have to last 5+ billion years to exist on earth.