Temperature is a measure of the average kinetic energy of particles of a thing. In the vacuum of space, there are very few particles, and they are mostly moving very very fast, which gives them high energy and high temperature.
I forget what happens at 40,000 m that causes the shift from cold atmosphere to “this is space” but that’s how the temperature is increasing – as you climb there are fewer and fewer particles, moving faster and faster.
Temperature is a measure of the average kinetic energy of particles of a thing. In the vacuum of space, there are very few particles, and they are mostly moving very very fast, which gives them high energy and high temperature.
I forget what happens at 40,000 m that causes the shift from cold atmosphere to “this is space” but that’s how the temperature is increasing – as you climb there are fewer and fewer particles, moving faster and faster.