Question

how many key layers does earth's atmosphere have?

Answer 1

There is the Troposphere - the closest layer to the ground and it is the layer that holds all of the weather for Earth. After that, there is the Stratosphere which is where weather balloons fly and where the ozone is (the ozone reflects some of the harmful UV radiation from the sun). After that, there is the Mesosphere which is the place where meteors and asteroids burn up (when they are inside our gravity). Next is the Thermosphere. This is the layer where the ISS flies and where the Aurora Borealis lights up the night sky in the North. And finally, there is the Exosphere. This is just a layer that is basically space, but still holds the gravity of Earth. I hope this helped! (P.S. - there are 5 layers of the atmosphere here on Earth)