Drunken Photons

 

The sun creates energy by fusing hydrogen into helium in the core. The process of taking four hydrogen nuclei and combining them to make one helium nucleus is a process called the proton-proton chain*.

 

*Fusing four hydrogen nuclei into one helium nucleus is called the proton-proton chain because one hydrogen nucleus is just a proton. The neat thing about a helium nucleus is that it is made up of two protons and two neutrons, and the total mass of the helium nucleus is 0.07% lighter than four protons. That extra 0.07% is converted to energy via Einstein’s famous equation, E=mc².  That may not seem like a lot of energy, but considering that there are trillions reactions occurring every second in the core, the energy adds up to quite a bit.

Gamma Ray represents energy

Fusion in the Sun

 

The energy given off by the proton-proton chain is emitted via high energy photons. These photons are able to escape the core and enter the radiation zone of the Sun.  It is here that something weird happens.

Photons collide with atoms, and give some of its energy to the atom. This lowers the energy of the photon.

Photons can also be re-emitted at higher temperatures. This causes the photon to actually gain energy.  A photon can either lose energy or gain energy. This path the photon takes is called a random path.  The best way to describe it is a drunken walk. If you have ever watched a drunk person walk, you notice that the next step he or she takes is totally at random.

Australia National Telescope Facility

 

In general, the photon emitted via the proton-proton chain is a highly energetic gamma ray. Via a series of collisions, that one photon ends up being thousands of lower energy light photons. However, it takes hundreds of thousands of years.