General Background:
- In principle, all matter emit photons of light. Every matter above absolute zero creates infrared light.
- Lighter elements, such as hydrogen and helium, are in general more fusible; while the heavier elements, such as uranium, thorium and plutonium, are more fissionable.
Nuclear fusion is an exothermic reaction:
The temperature at the core center of the sun is about 15 million Celsius or 16 million Kelvin. Due to the Sun's gravity, gas particles experience high pressures and temperatures. They possess sufficient kinetic energy to cause 2 positively-charged hydrogen ions to collide and form 1 helium molecule thereby releasing (gamma ray photon of) energy equivalent to 1% mass of an electron.
The mass of this helium atom is about 0.8% less than the mass of the four hydrogen atoms which combined to form a helium atom. This burning of hydrogen into helium would release about 0.7% of the mass equivalent of the energy.
Born at the core center of the Sun, this gamma ray photon is set to travel to the outer surface of the sun (photosphere) because that region is cooler and less dense. However this journey involves traversing 696'000 km (432'000 miles) of dense gas (electron deprived ionized plasma) and takes a million years.
Along their outward journey, photons inside the Sun loose energy and gradually degrade from Gamma rays, down to X-rays, down to UltraViolet light & eventually visible light... while being carried by a gas molecules which cool by the time they reach the photosphere causing them next to sink back into the center core to fuse with other hydrogen particles before attempting another cycle to the edge again!
Refer to: www.physics.info
