ESA spacecraft sees a kaleidoscope of color in Mars' atmosphere | Space photo of the day for Sept. 26, 2025

Mars' atmosphere has been of interest to scientists for decades, especially as humanity looks to set up outposts on the Red Planet. Recently, the European Space Agency's ExoMars Trace Gas Orbiter gave us a more detailed look at the thin shell of air that sits above the limb of Mars

What is it?

Creating a composite photograph of the images taken by the Color and Stereo Surface Imaging System (CaSSIS) aboard the Trace Gas Orbiter, ESA scientists found that the dust and gas layers of Mars' atmosphere are delicate and sit close together, similar to a "mille-fueille" pastry.

Mars' atmosphere is extremely thin and is composed of mostly carbon dioxide, with small amounts of nitrogen, argon and trace gases thrown in. Yet despite its thinness, it's far from static, as Mars' air can whip up dust storms that help shape short term weather.

Where is it?

This image was taken in Mars' shadow in close orbit.

Why is it amazing?

Thanks to these new images, experts have a much more detailed view of the composition of Mars' atmosphere. Each strip contains layers only a few miles (several kilometers) thick. Above about 25 miles (40 km), the layers are thought to consist mainly of tiny ice grains, while below that altitude, dust is more dominant. Subtle differences in the color between the bands hint at the chemical composition and concentration within the atmosphere.

These particles help control how sunlight is absorbed and scattered, which in turn affects the heating and cooling of different parts of the atmosphere. By mapping how the layers are arranged vertically, scientists can better predict how the atmosphere evolves daily, seasonally and even across decades. The researchers published their images, and analyses of them, in a recent issue of the journal Science Advances.

Want to learn more?

You can read more about Mars' atmosphere and the ExoMars Trace Gas Orbiter.