<P> Supernova nucleosynthesis within exploding stars by fusing carbon and oxygen is responsible for the abundances of elements between magnesium ( atomic number 12 ) and nickel ( atomic number 28 ) . Supernova nucleosynthesis is also thought to be responsible for the creation of rarer elements heavier than iron and nickel , in the last few seconds of a type II supernova event . The synthesis of these heavier elements absorbs energy ( endothermic ) as they are created , from the energy produced during the supernova explosion . Some of those elements are created from the absorption of multiple neutrons ( the R process ) in the period of a few seconds during the explosion . The elements formed in supernovas include the heaviest elements known , such as the long - lived elements uranium and thorium . </P>
<P> Supernova nucleosynthesis within exploding stars by fusing carbon and oxygen is responsible for the abundances of elements between magnesium ( atomic number 12 ) and nickel ( atomic number 28 ) . Supernova nucleosynthesis is also thought to be responsible for the creation of rarer elements heavier than iron and nickel , in the last few seconds of a type II supernova event . The synthesis of these heavier elements absorbs energy ( endothermic ) as they are created , from the energy produced during the supernova explosion . Some of those elements are created from the absorption of multiple neutrons ( the R process ) in the period of a few seconds during the explosion . The elements formed in supernovas include the heaviest elements known , such as the long - lived elements uranium and thorium . </P>
where did the heavier elements on earth come from
where did the heavier elements on earth come from
Supernova nucleosynthesis
Supernova nucleosynthesis