Hvorfor det er plausibelt å tro at universet kan være 13,7 mrd år gammelt
Fra NASAs website: Carbon and oxygen were not created in the Big Bang, but rather much later in stars. All of the carbon and oxygen in all living things are made in the nuclear fusion reactors that we call stars. The early stars are massive and short-lived. They consume their hydrogen, helium and lithium and produce heavier elements. When these stars die with a bang they spread the elements of life, carbon and oxygen, throughout the universe. New stars condense and new planets form from these heavier elements. The stage is set for life to begin. Understanding when and how these events occur offer another window on the evolution of life in our universe. Min amatørforklaring Først ble elementer med lavere nummer fra det periodiske system slynget ut i universet, og dannet stjerner av den relativt kortlevde sorten. Når disse stjernene igjen døde, så slynget de ut de nødvendige karbon-molokyler (og oxygen) til at planeter som jorda kunne bli til. Tenker man seg en stjerne kan leve ...