Atmosphere of Earth However, polar stratospheric or nacreous clouds are occasionally seen in the lower part of this layer of the atmosphere where the air is coldest. The stratosphere is the highest layer that can be accessed by jet-powered aircraft. The troposphere is the lowest layer of Earth's atmosphere. It extends from Earth's surface to an average height of about , although this altitude varies from about at the geographic poles to at the Equator, with some variation due to weather. The troposphere is bounded above by the tropopause, a boundary marked in most places by a temperature inversion (i.e. a layer of
Day of the Animals claiming that chemical waste released into the atmosphere has dangerously depleted the ozone layer, which protects all life from the sun's radiation. On the mountain, the hikers stumble upon a camp where a fire is burning and coffee cups are ready to be filled, but nobody is around. Steve says the campers will soon be back. He leads the hikers to a nearby spot to bed down for the night. They build a fire, and while Daniel pulls Steve aside to tell him that something strange is going on in the woods. Steve asks him not to say anything to