What phenomenon occurs in the mesosphere?

The mesosphere is the layer of Earth's atmosphere that lies above the stratosphere and below the thermosphere, extending from about 50 to 85 kilometers (31 to 53 miles) above the surface. One of the key phenomena that occurs in the mesosphere is the occurrence of meteors, commonly referred to as "falling stars."

This phenomenon takes place because as meteoroids enter the Earth's atmosphere at high speeds, they encounter the relatively dense air in the mesosphere. The friction between the meteoroids and the air causes them to heat up and emit light, creating the bright streaks we see in the night sky. Most meteors burn up completely in this layer of the atmosphere before they can reach the surface of the Earth.

Other options describe different processes or occurrences in various atmospheric layers. For example, cloud formation largely occurs in the lower atmosphere, particularly within the troposphere, while ozone creation is predominantly associated with the stratosphere, where the ozone layer is located. Jet streams are typically found in the upper troposphere, not the mesosphere. Thus, the occurrence of falling stars or meteors is specifically linked to the unique conditions and interactions that take place in the mesosphere.