what are the four atmosphere layers?
["Troposphere. The troposphere starts at the Earth's surface and extends 8 to 14.5 kilometers high (5 to 9 miles). ... ", 'Stratosphere. The stratosphere starts just above the troposphere and extends to 50 kilometers (31 miles) high. ... ', 'Mesosphere. ... ', 'Thermosphere. ... ', 'Ionosphere. ... ', 'Exosphere. ... ', 'Credit: NASA/Goddard.']