Here's why:

* Mesosphere: This layer sits above the stratosphere and below the thermosphere. It's characterized by decreasing temperature with altitude, reaching very cold temperatures.

* Friction: As meteors enter the Earth's atmosphere at high speeds, they encounter increasing air density. This friction generates intense heat, causing the meteor to glow and often disintegrate completely.

While some smaller meteors might begin to burn up in the upper stratosphere, the majority experience their most intense burning within the mesosphere.