The floor in the middle of the fourth layer is the atmosphere of the stratosphere and up to another 40 kilometers to the floor with very little ozone. The temperature is decreased When moving up to find molecules. Gas in the form of ions, such as O2, NO + in the atmosphere, the temperature will drop below the level of -100 oC.
Height 90 kilometers from the surface. Temperatures will remain in this area that the mesopause, which is the boundary between this layer and the next layer.
Layer Mesosphere. Help cover a meteorite from outer space on a meteor coming into this class. It was burned down remains the most part.