3. Atmospheric Composition and Its Influence
The colour of lightning is largely influenced by the makeup of the atmosphere. With minor concentrations of other gases, nitrogen and oxygen make up most of the Earth’s atmosphere. Lightning stimulates these gas molecules as it moves through the atmosphere, which results in light emission at particular wavelengths.
About 78% of our atmosphere includes nitrogen, which is very vital in producing blue lightning. The blue and purple ranges of the visible spectrum are emitted by nitrogen molecules energising themselves from the electrical discharge. In the upper atmosphere, where the air is thinner and nitrogen relative to other gases makes more of an impact, this emission is more noticeable.