Atmospheric Composition and Life
|Carbon dioxide (CO2)||95.32 %|
|Nitrogen (N2)||2.7 %|
|Argon (Ar)||1.6 %|
|Oxygen (O2)||0.13 %|
|Water (H2O)||0.03 %|
|Carbon monoxide||0.07 %|
The quantities of ozone and water vapour are so small that, unlike the ozone layer on Earth, there is no protective layer on Mars that blocks out ultraviolet rays. The ultraviolet radiation reaches the soil unhindered and can destroy any organic molecules. For some, this fact is enough to argue that life is impossible on Mars.
Others, however, point out that there are ecological niches beneath the surface that may once have favoured the development of bacteriological colonies. These colonies may still persist to this very day. This possibility is a hot topic for discussion that will last for some time without other, more solid, evidence.