Molecular Origins of Brain and Body Geometry by Antonio Lima-de-Faria

Author:Antonio Lima-de-Faria
Language: eng
Format: epub
Publisher: Springer International Publishing, Cham

The three principal energy sources in stars, in order of occurrence during a typical star’s life, are: (1) gravitational energy (due to attraction between bodies), (2) thermonuclear reactions (proton-proton interactions) and (3) thermal energy (particle movement). Each of these has been estimated for the Sun as well as for other stars. The chemical composition of the Sun has also been determined to be about 94 % hydrogen, 6 % helium, and 0.1 % of all the heavier elements.

The Sun’s gravitational contraction can supply it with energy to continue to shine for 8 × 109 years, but nuclear reactions provide the principal energy source consisting of hydrogen burning into helium and helium burning into heavier elements.

The age of the Sun is also known. The formation of our solar system occurred 4.5 billion years ago and the universe started almost 14 billion years ago (Scharf 2012). Hence, there is a time scale for stellar evolution as there is one for biological evolution. The difference is mainly one of magnitude.

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