atoms in our bodies were created inside a star, under immense pressure and huge temperatures, which are difficult to understand for us.
"We are all stardust," the phrase is from Carl Sagan whom you know I admire . And only poetry but rather summarizes the result of centuries trying to understand how stars and the evolution of the universe. It all began in the nineteenth century when scientists began to wonder where he came the sun's energy . No chemical reaction or physical process known could provide the energy needed during the time it was there our planet.
When it was discovered nuclear fusion is the process which saw the immense amount of energy from hydrogen. And as all sources of energy, a waste generated in return. In fact, the calcium in our bones, the iron in hemoglobin, carbon, nitrogen and oxygen in different tissues and cells that make up our bodies do not exist at the beginning of the universe. In the first five minutes after Bing Bang formed the first atoms, hydrogen, helium and small traces of deuterium and lithium (you can read more details La Bella Theory ) Only a fraction of the approximately 115 items known. Later came the first stars that initially had the same composition. Since then various processes of melting, called nucleosynthesis, have been generating more and more heavy atoms like calcium or iron from less massive elements. The problem is that successive fusion reactions contribute less energy each time.
Above iron, nuclear fusion does not produce energy but absorbs it. To get heavier elements are thought to be two main processes. On the one hand, a supernova, that is, the explosion of a star. The enormous energy released is channeled only in part, to the formation of heavier nuclei. Atoms like our rings gold and uranium from nuclear reactors fission. On the other the slow neutron absorption by some heavy atoms further increases its atomic number. It is a slow process that takes thousands of years and that complements the former.
The sum of both methods has provided us with gold rings, nuclear reactors and, above all, essential to life as copper, zinc and iodine. Ashes of stars need to give us life.
Category: Physics, Chemistry
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