Why does the temperature increase in the stratosphere and the thermosphere?

In the stratosphere, temperature increases with altitude due to the absorption of ultraviolet (UV) radiation by the ozone layer, which warms the air. In the thermosphere, temperature rises dramatically as solar radiation is absorbed by sparse gas molecules, causing them to move more rapidly. This increase in kinetic energy translates to higher temperatures, despite the thinness of the atmosphere. Overall, both layers experience temperature increases due to their interactions with solar radiation.