You are standing under
100 kilometers of air.
Everything you have ever called weather happens in the first 12 kilometers.
MassThis layer contains 80% of the atmosphere's total mass, and essentially all weather.
TemperatureIt falls as you climb: about 15°C at sea level, about −56°C at 12 km.
Cruising altitudeCommercial jets cruise near the top of this layer, 10–12 km up.
Here, the ozone layer is absorbing the sun's ultraviolet light so your skin doesn't have to.
Ozone layerPeak concentration around 20–30 km. It absorbs most of the sun's UV-B and UV-C radiation.
Temperature, reversedHere it rises with altitude — from about −56°C to about −2°C at 50 km — because ozone absorbs UV directly.
Thin airBy the top of this layer, the air is roughly 1,000 times thinner than at sea level.
This is where shooting stars actually happen — meteors burning up, 50 to 85 kilometers up.
Coldest layerAbout −86°C at its top — the coldest natural temperature in Earth's atmosphere.
MeteorsMost meteors burn up here, from friction with the thin air.
100 km.
By international agreement, this is where space begins.
The Kármán lineThe internationally recognized boundary of space sits inside the thermosphere, just above the mesosphere.
The auroras happen here. So does the International Space Station.
AurorasMostly 100–300 km up, where charged solar particles strike atmospheric gases.
Heat you couldn't feelTemperature rises sharply here, reaching 500°C to 2,000°C depending on solar activity — but it would not feel hot. The air is too thin to transfer much heat.
ISSThe International Space Station orbits inside this layer, at about 400 km.
Up here, a single gas particle can travel hundreds of kilometers without meeting another.
Outermost layer600 to 10,000 km — the transition to the vacuum of space.
No ceilingThere is no firm upper boundary. It blends into interplanetary space.