Why is the CNO cycle essential for life in the Universe?
The CNO cycle is essential as theoretical models show that the CNO cycle is the dominant source of energy in stars heavier than about 1.5 times the mass of the sun, and with out the sun burning nothing would live. While in the stars with the mass of our sun or less, the proton-proton chain is more important. In the CNO cycle, four protons fuse using carbon, nitrogen and oxygen isotopes as a catalyst to produce one alpha particle, two positrons and two electron neutrinos . The positrons will almost instantly annihilate with electrons, releasing energy in the form of gamma rays. The neutrinos escape from the star carrying away some energy. The carbon, nitrogen, and oxygen isotopes are in effect one nucleus that goes through a number of transformations in an endless loop. the nitrogen used is Nitrogen-14, Nitrogen-13 and Nitrogen-15 im pretty shure.
