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Tritium is a heavy isotope of hydrogen, with one proton and two neutrons. For more information, see: For a lesson about this topic, see: |
At the core of the sun, gravity pulls all of the mass inward and creates an intense pressure. The pressure is high enough to force atoms of hydrogen to come together in nuclear fusion reactions. Two atoms of hydrogen are combined to create helium-4 and energy in several steps:
- Two protons combine to form a deuterium (hydrogen atom with one neutron), a positron (similar to electron, but with a positive charge) and a neutrino.
- A proton and a deuterium atom combine to form a helium-3 atom (two protons with one neutron) and a gamma ray.
- Two helium-3 atoms combine to form a helium-4 (two protons and two neutrons) and two protons.
These reactions account for 85% of the sun's energy. The remaining 15% comes from the following reactions:
- A helium-3 and a helium-4 combine to form a beryllium-7 (four protons and three neutrons) and a gamma ray.
- A beryllium-7 captures an electron to become lithium-7 (three protons and four neutrons) and a neutrino.
- The lithium-7 combines with a proton to form two helium-4 atoms.
- The helium-4 atoms are less massive than the four hydrogen atoms that started the process, so the difference in mass was converted to energy as described by Einstein's theory of relativity (e=mc2).
The energy is emitted in various forms of light (ultraviolet light, x-rays, visible light, infrared, microwaves and radio waves). The sun also emits energized particles (neutrinos, protons) that make up the solar wind. This energy strikes Earth, where it warms the planet, drives our weather and provides energy for life. We are not harmed by most of the radiation or solar wind because the Earth's atmosphere protects us.
Freudenrich, Ph.D., Craig. "How the Sun Works." 17 October 2000. HowStuffWorks.com. science.howstuffworks.com/sun.htm 14 April 2008.