The mesosphere is located above the stratosphere. It starts at about 50 km above the surface of the Earth and ends about 85 km above the surface of the Earth. The area between the mesosphere and the stratosphere is called the stratopause.
Not very much is known about the mesosphere because it is too high for airplanes or weather balloons to reach, and it is too low for satellites. Sometimes scientists can get information about the mesosphere as rockets pass through it, but these trips are very short.
We do know that many meteorites burn up in the mesosphere. As a result, there are a lot of iron and other metal particles in this part of the atmosphere.
Like the troposphere, the temperature goes down as you travel up in the mesosphere. That means it is colder at the top of the mesosphere than at the bottom.
Very rarely, clouds can form in the mesosphere. They are called noctilucent clouds or polar mesospheric clouds. They form at the very top of the mesosphere. This area is called the mesopause. The clouds form out of tiny freezing ice crystals. Most of the time these clouds are not visible from the surface of Earth.