A team of researchers has uncovered evidence of its origins in the atmosphere, where carbon dioxide bathed in ultraviolet sunlight reacted to form a mist of carbon molecules that rained onto the planet's surface.
The scientists made a startling observation when they observed that the atmosphere of Mars dramatically ballooned outwards because of a void created due to a powerful gust of solar wind.
When future astronauts explore Mars's polar regions, they will see a green glow lighting up the night sky. For the first time, a visible nightglow has been detected in the martian atmosphere by ESA's ExoMars mission.
Sunlight on Mars interacts with iron-rich dust that hangs in the atmosphere. This ultimately scatters lower-frequency red light through the sky during the day. At twilight, however, the red light is filtered away and the sky glows a cool blue.
