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
Ionizing radiation found in space can also cause single-event upsets in digital circuits. The electrical effects of ionizing radiation are exploited in gas-filled radiation detectors, e.g. the Geiger-Muller counter or the ion chamber. In general, ionizing radiation is harmful and potentially lethal to living beings but some types have medical applications in radiation therapy for the treatment of cancer and thyrotoxicosis. Most adverse health effects of exposure to ionizing radiation may be grouped in two general categories: The most common impact is stochastic induction of cancer with a latent period of years or decades after exposure. For example, ionizing radiation is the