Why is the sky blue?

I took this shot during our Caramoan trip last April

There's a new study that says the color of the sky, which is typically blue, has something to do with certain minerals like phosphorus, some ancient algae, and rocks. How did that happen?


Well, according to that study which I read on Yahoo News (my only source of news each morning, afternoon, and night), the sky could probably have been orange around 2 billion years ago. So I'm thinking... just like Mars? @_@ No wonder atsronomers are saying Mars is showing signs of life. Maybe Earth was like Mars 2 billion years ago! Anyway, I digress...


These research scientists were saying that during that time, the earth's chemistry was composed of mostly methane (CH4), which caused the orange hue at the horizon (Does this mean Mars smells like f*%t?). While today, Earth's atmosphere is mostly composed of oxygen and nitrogen. When sunlight hits it (which is composed of the rainbow's colors ---RGBIV), blue is the one being mostly reflected.