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
Radiation effects from the Fukushima Daiichi nuclear disaster to poison centres around the world after taking iodine tablets in response to fears about harmful levels of radiation coming out of the damaged nuclear power plant in Fukushima. In Operation Tomodachi, the United States Navy dispatched the aircraft carrier and other vessels in the Seventh Fleet to fly a series of helicopter operations. A U.S. military spokesperson said that low-level radiation forced a change of course en route to Sendai. The "Reagan" and sailors aboard were exposed to "a month's worth of natural background radiation from the sun, rocks or soil" in an hour and the carrier was repositioned.