In the modern sense of the word, it refers to whatever transition is presumed to have occurred between a universe with no living things (it is generally accepted that living things were not present in the original quark-gluon plasma of the [[big bang]]), and the present universe. | In the modern sense of the word, it refers to whatever transition is presumed to have occurred between a universe with no living things (it is generally accepted that living things were not present in the original quark-gluon plasma of the [[big bang]]), and the present universe. |