Atmosphere of Earth trend begin above 11 km, where the temperature stabilizes through a large vertical distance through the rest of the troposphere. In the stratosphere, starting above about 20 km, the temperature increases with height, due to heating within the ozone layer caused by capture of significant ultraviolet radiation from the Sun by the dioxygen and ozone gas in this region. Still another region of increasing temperature with altitude occurs at very high altitudes, in the aptly-named thermosphere above 90 km. Because in an ideal gas of constant composition the speed of sound depends only on temperature and not on the gas
The empire on which the sun never sets at the present time." In 1821, the "Caledonian Mercury" wrote of the British Empire, "On her dominions the sun never sets; before his evening rays leave the spires of Quebec, his morning beams have shone three hours on Port Jackson, and while sinking from the waters of Lake Superior, his eye opens upon the Mouth of the Ganges." Daniel Webster famously expressed a similar idea in 1834: "A power which has dotted over the surface of the whole globe with her possessions and military posts, whose morning drumbeat, following the sun and keeping company with the hours, circles the earth