A Beautiful Planet calls Earth's atmosphere "a delicate cocoon of air that shields us from our star's radiation." Of course, the atmosphere doesn't completely block electromagnetic radiation from the Sun; without some sunlight reaching the surface, plants could not harvest the Sun's energy, and practically no life as we know it could exist. The atmosphere's ozone layer does filter out much of the harmful ultraviolet light (or "UV rays") produced by the Sun. UV rays can cause skin cancer, and catastrophic damage to the ozone layer may have contributed to Earth's most extensive mass extinction of species ever, the End-Permian extinction (also known
Atmospheric Chemistry Suite than the PFS spectrometer of Mars Express orbiter. Of particular interest to this astrobiology mission, is the detection and characterization of the atmospheric methane (), as it may be of geological or biological nature. Large differences in the abundances were measured between observations taken in 2003, 2006, and on 2014 NASA reported that the "Curiosity" rover detected a tenfold increase ('spike') in methane in the atmosphere in late 2013 and early 2014. This suggestes that the methane was locally concentrated and is probably seasonal. Because methane on Mars would quickly break down due to ultraviolet radiation from the Sun and