The mesosphere is the coldest layer of Earth's atmosphere. Located between 50 and 80 kilometers above the surface, it has an average temperature of about -85 degrees Celsius. The top of the mesosphere is the coldest area of the Earth's atmosphere, with temperatures reaching as low as -173 degrees Celsius.
This extreme cold is caused by the lack of heat sources in the mesosphere. Unlike the lower layers of the atmosphere, which are heated by the sun and the Earth's surface, the mesosphere receives very little solar radiation. This is due to the thinness of the air at this altitude, which limits the absorption of energy.
The mesosphere is also where most meteors burn up, creating the bright streaks of light we see in the night sky.
