Question

The sky of early Earth was probably pinkish-orange. As life became established, the sky turned blue. What was responsible for the color change?

Answer 1

Earth’s atmosphere had little to no oxygen. It was composed of carbon dioxide, water vapor, and nitrogen, with lesser amounts of carbon monoxide, hydrogen sulfide, and hydrogen cyanide. Because of these gases in the atmosphere, the sky was probably pinkish-orange. Meaning once earth obtained more oxygen the sky turned blue.