Future of Earth the ozone layer that protects the surface from ultraviolet (UV) radiation from the Sun. An increase in UV-B radiation of only 10–30% is sufficient to cause a significant impact to life; particularly to the phytoplankton that form the base of the oceanic food chain. A supernova explosion at a distance of 26 light years will reduce the ozone column density by half. On average, a supernova explosion occurs within 32 light years once every few hundred million years, resulting in a depletion of the ozone layer lasting several centuries. Over the next two billion years, there will be about 20
The City of the Sun to observe the stars and, using astronomical instruments, to take account of all their movements. It is their job to indicate the times most favorable for generation and for agricultural labors, acting in this way as intermediaries between God and human beings. In Trento's Civic Library, there is kept a 1602 manuscript of "The City of the Sun" (shelf mark BCT1-1538), discovered in 1943 by Italian historian Luigi Firpo. It is considered the most ancient manuscript copy that has survived to present time. The text arrived at the Library through the baron Antonio Mazzetti 's (1781–1841) bequest. He was a