The Fires of Life Solar fire, cellular fire. Energy from very energetic solar photons enters the biosphere as visible light and exits as heat that radiates back into the deep cold of outer space. Between the energy's coming and going, the photons captured by photosynthesis power the intermediate processes that organize the structures of life and generate the fire of life.
Photosynthesis generates biofuels in solar-powered cellular factories.
During photosynthesis, the captured photons split water into hydrogen and oxygen. The oxygen is released into the air to join the pool of atmospheric oxygen gas, while the hydrogen combines with carbon dioxide to give rise to organic molecules like edible sugars. Subsequent metabolism uses these organic molecules for structure building, and as fuel for doing work. During metabolism, biomolecules recombine with oxygen to form water and carbon dioxide, while the energy created does all manner of biological work and is finally released as heat. In this sense, all fire is the fire of life, for the oxygen that combusts with wood and fossil fuels has also been made by life during photosynthesis.