Stratosphere: The stratosphere of a terrestrial planet is the second-lowest member of the atmosphere. On Earth, the stratosphere starts atop the troposphere at approximately 10 kilometers above mean sea level, and terminates roughly 50 kilometers above mean sea level. In fact, geologists understand that the Earth’s ozone layer exists within the stratosphere, which absorbs intense ultraviolet rays from the sun and converts them into heat. The air of the stratosphere tends to be thinner, and also increases in temperature with higher altitudes. The stratosphere lacks many of the weathering characteristics of the underlying troposphere. As a result, airplanes tend to experience less turbulence when flying at the lower brim of the stratosphere, rather than in the troposphere. The next member of the atmosphere above the stratosphere is the mesosphere.