Where does energy from a star come from?

Answer 1

Hydrogen fusion primarily.

Answer 2

Nuclear fusion.

The energy in stars is a result of the force of gravity acting upon the very large mass of the star. This creates pressures and densities at the center of stars capable of fusing the nuclei of atoms (mostly hydrogen into helium). This nuclear reaction is sustained so long as sufficent fuel and mass are present, and the energy produced is vast.

Answer 3

The class of reactions that release so much energy are called Thermonuclear events. They come from the fusion of smaller nuclei to form larger nuclei of elements. Our sun is a star that converts Hydrogen into Helium plus some stray neutrons/protons. Other stars form other elements such as carbon and nitrogen from similar fusion reactions.

Answer 4

It depends upon your school of thought. Some will say that a star is driven by nuclear reactions. Others will say they are driven (and they'll include the Universe) by electrical reactions. The later identify themselves with the Electric Universe.

The Electric Universe makes sense to me because one doesn't have to fish around looking for a reason why the surface of the sun is hotter than it's interior.
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