What is the actual colour of lightning?

Question

sometimes it is violet sometimes pink and sometimes even blue....why is that so?

Answer 1

silver

Answer 2

The color of lightning that you see is affected by the air around the spark.  Lightning occurs when a large static charge moves from one place to another.  This charge excites the air around it, and then that air "calms down," for lack of a better term.

When the air releases its energy in the form of light, the color of light that is released depends on the atoms or molecules that were excited in the first place.

Lightning usually appears blue-white because oxygen releases blue light, whereas nitrogen, the other largest component of the air we breathe, releases white light.

If the air is dirty, or there is a high level of something like sulfur dioxide, the lightning may appear yellowish.

Answer 3

lightning is usually colourless but various things determine the apparent colour of lightning. The main one is distance. The longer the path of the light from the lightnintg through the atmosphere, the redder the stroke seems. In photographs of multiple lightning strikes, the nearest and furthest can be deternined by the colour of the strike.

Different particulate matter in the atmosphere also affects the colour of the lightning and there is some colour variation, but not a lot, from the temperature of the discharge. I have seen yellow, orange, pink, purple, blue and green lightning at various times. You will see more colours if you photograph it at night.

another opinion from NewScientist's 'Last Word' section:

"A lightning plasma is quite dense, because the degree of ionisation in the air near the lightning is high. It therefore gives off a lot of infrared, visible light and ultraviolet. A lightning flash consists mainly of light emitted at all wavelengths, plus line and band emissions at characteristic wavelengths from the atoms and molecules present in the surrounding air * mostly argon, oxygen, nitrogen and water. The lightning we see contains contributions from all these sources and the colour depends on the kind of atoms in the air.

"A discharge in dry air looks white because there are few strong visible lines those which exist are mainly blue and violet * and the bulk of the visible light is emitted in a continuous spectrum. If water vapour is present, then the hydrogen atoms in the water create a very strong red line (known as the Balmer alpha line) that can dominate the visible line emission. If this line is superimposed on the white background created by the other atoms in the plasma, it would explain the reddish appearance of some lightning flashes. The reddish colour will be easier to see at night. The variability in the amount of red in a series of lightning flashes is explained by variations in the amount of water in the air. In addition, water vapour or tiny water droplets are more easily ionised and their hydrogen atoms more easily excited than the hydrogen in large water droplets * the latter must first evaporate, which takes longer than the duration of a single flash. It is possible that large droplets were broken up during the long series of localised flashes reported by your correspondent, thereby creating an exceptional redness."