I'm wondering say in stars such as VY Canis Majoris and in other super/hypergiants alike, what determines the nuclear fusion process at say the core of the star and at halfway out of the radius of the star, taking into consideration the speed of light.
Does this have any effect on the star? Say the sun as a main sequence star a fusion reaction at one part of the star and another at another point the distance in time between the two would be seconds right? So what if this is hours? Is there an effect?