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
Day of the Sun leaders. Festivities are not confined to the date. Commemorations occur from 16 February, which is the birthday of Kim Jong-il, during what is known as the Loyalty Festival. Celebrations in April around the Day of the Sun are called the Sun Festival. The day itself is followed by two days of rest, making it a three-day holiday. Kim Il-sung was born on 15 April 1912 in the village of Mangyongdae, which is now a suburb of North Korea's capital Pyongyang. He has been long identified with the Sun and is frequently called "Sun of the nation". He adopted his name