A
sunflower reacts to the
energy of
photons;
energy emanates from
thermonuclear reactions in the
sun; makes things
grow, i.e. do
work; is the driving
force of
evolution, and the means of
economic activity in
human social affairs; it can be
transformed and or
stored in many forms, e.g.
solar energy,
nuclear energy,
light,
heat,
kinetic energy,
potential energy, etc.; is the central component in all of
science, e.g.
chemistry:
activation energy,
entropy,
bond energy, etc., or
thermodynamics:
internal energy,
Gibbs free energy, etc.; it is equivalent to
mass:
E=mc2 and has its mysteries, e.g.
dark energy.
