Like Earth, the Martian atmosphere is composed of gases released from the interior by way of volcanism. Mars' atmosphere is 95% carbon dioxide, 2% nitrogen, and 1.6% argon. In addition,
traces of water vapor, carbon monoxide, oxygen, ozone, krypton, neon, and xenon are present.
Unlike Earth, the Martian atmosphere has no ozone layer, which means the planet surface is fully-exposed to ultraviolet radiation. In addition, the atmosphere is tenuous and cannot scatter
the shorter wavelength radiation from the Sun (the phenomenon that makes the Earth's sky blue). As a result, the Martian sky is pink.
