I am writing a novel where a habitable moon orbits a purple gas giant. In looking here and elsewhere I'm finding it incredibly hard to get a sense of the elements-breakdown of elements that would be present in a purple gas giant. This planet does NOT have to be habitable/have breathable atmosphere.
It's my understanding that with electrical charge that Argon appears purple. So my thought is to have a planet with Argon as dominant element. Ideal conditions would include the capacity for electrical storms/lightning that would make the planet glow purple(s).
So questions attached to this are: *Whether planet would likely have a solid core (if so what of)? *What other elements might need to be present to charge the atmosphere?
Another approach might negate the need for the planet to be a "gas" giant. Recent research posits that purple single-celled organisms ma have once dominated Earth's surface.
"There are a few variations of the Purple Earth hypothesis among scientists. DasSarma's research has focused on halophiles, microorganisms that still exist today in environments with a high concentration of salt, such as the Great Salt Lake and the Dead Sea. They use their strong purple retinal pigment -- the same visual pigment in the eyes of humans -- to absorb light and generate growth, and he says it's likely that they've been present on Earth for millions, if not billions, of years."
So - could this alternate planet be one with big salty ocean full of purple dominant organisms and/or purple bacteria?
Either way-what is a reasonable breakdown of elements (e.g. 74% Argon (or Neon)/18% Nitrogen/5% Oxygen/1.6% Carbon Dioxide/0.9% Water Vapor/ 0.5% Trace)