Let’s start from the beginning, with the stages of a star’s life cycle. Their stages follow a pattern similar to some of the life cycles we see here on Earth. A star begins its life as a cloud of dust …show more content…
If you were inside a star you would not be able to tell which way is up, because you would only be able to see a brief distance through the gases, and circumstances would be mostly the same all through the region you would see. Under these conditions, light will flow upwards only if more light would happen to come in from lower layers than from upper ones. Since there is no way of telling which way is up (and even if there were the pieces of atoms which make up the plasma inside a star wouldn't care which way is up), it is required that each layer be brighter than the layer above it. In fact, if we describe a layer as the range that you can see through the gas looking up or down, then at the bottom, the gas must be brighter than the top by about the surface brightness of the star. In the interior parts of a star (the radiative core), heat flows out, by process of diffusion. Diffusion, in this case, refers to the photons of light that can only go through the gas for a considerable distance before they are scattered, bounced off of, or consumed by the gas