Layers of the Atmosphere
With the moon for scale
This is the outer layer of Earth’s atmosphere. As the top of the Thermosphere varies in height, depending on the sun, the base of the Exosphere varies accordingly. The outer limit of the exosphere is not precisely defined. If a particle is caught in Earth’s gravity to where it will come back to the surface eventually, it’s said to still be in the atmosphere. If radiation from the sun is stronger than the gravitational pull of the Earth, causing the particle to not come back to earth, then that would be the outer limit of the Exosphere. This is around 190,000km. As far as what is observable from a visual standpoint (visual to tools that can see ultra-violet), the visible part of the exosphere ends at about 10,000km. The air is extremely thin at this layer.
The Aurora (Northern and Southern Lights) mostly occur here. The air density is so low that this layer is considered to be in space (space is generally considered to start at 100km). Temperatures range from 500° C to 2000° C, however the gasses that are that hot are so thin that if you were to spend time in that area with normal clothing (and not considering direct sunlight hitting you and not being able to breath) the surrounding air would not be enough to keep you warm. You would likely freeze.
Space Shuttle Endeavor in the Thermosphere. The blue is the Mesosphere, the white is the Stratosphere, and the orange is the Troposphere. The Thermosphere is the second-highest layer of the atmosphere. This picture was taken from the Internation Space Station when the Endeavor was flying a mission there.
This layer has the coldest temperatures of the atmosphere. Temperatures go as low as -143° C near the top. It’s difficult to study this layer as aircraft can’t travel there, and satellites orbit above it. Very high altitude clouds form near the North and South poles. Additionally, meteors generally burn up in this layer.
This is the second layer of Earth’s atmosphere. The temperature is fairly stable so there are little fluctuations in wind due to convection. Therefor, aircraft prefer to fly there due to decreased turbulence. The air is 1000 times thinner at the top of the layer, so aircraft cannot fly any higher. Additionally, ozone is commonly found and absorbs ultra-violet radiation from the sun. Temperatures get warmer as you go higher in this layer. Since heat naturally rises, this is why the turbulence is lower. Unique upper-atmosphere lightning forms very occasionally at this layer.
This is the first and lowest layer of the Earth’s atmosphere. The majority of the mass of the atmosphere is in the Troposphere (75-80%). Air temperature decreases as you get closer to the top of this layer. The maximum height is variable. It can be up to 20km at the equator and as low as 7km at the poles in winter. The majority of clouds occur in this layer.