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
Journey of Apollo 15 to the Moon them on a lunar-bound trajectory. About 485 lb (220 kg) of liquid oxygen (LOX) was lost through an open vent of the S-IVB after the rocket was pitched down too quickly after cutoff. One of the windows of the Apollo 15 CSM was specifically designed to transmit ultraviolet radiation, permitting the crew to acquire UV photographs of the Earth and the Moon. These photographs began as soon as they reached Earth orbit and would continue throughout the mission. During times when they were not using the window, Mission Control had them place a cover over the window that blocked the