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 Songs of Distant Earth would have to carry to first accelerate to the speeds required to travel such great distances within an acceptable time, and then decelerate upon approaching the destination. This limitation is overcome however with the development of the Quantum Drive less than a hundred years before the Sun is set to become a nova. This scientific break-through allows the construction of a fleet of manned interstellar vehicles, including the Starship "Magellan". The "Magellan" escapes the Earth three years before the Sun explodes, an event that is witnessed by the "Magellan"'s crew. In the intervening years the colony on Thalassa loses contact