exospheres
Highest atmospheric layers
Exospheres is the plural of exosphere, the outermost layer of a planet's atmosphere where gas molecules can escape into space.
Earth's exosphere begins about 300 miles up and gradually fades into the vacuum of space with no clear boundary.
Other planets and moons have exospheres too: Scientists study the exospheres of Mars and Mercury.
Gaseous layers surrounding celestial bodies
- ionospheresCharged upper atmospheric regions
- stratospheresAtmospheric layers above weather
- atmospheric layersDistinct altitude zones surrounding Earth
- EarthOur world
Mars · Mercury · Venus · hydrogen · helium · rarefied · tenuous · outermost
Science of celestial motion
- dragResistance through fluid
- altitudeMeasured height above reference
- atmospheric reentrySpacecraft returning through air
- space stationsCrewed spacecraft in orbit
ISS · Hubble · collision · debris · tracking · decay · solar activity · mission planning
Eleventh element, highly reactive
- potassiumNineteenth element, symbol K
- argonUnreactive element eighteen
- regolithFragmented covering over bedrock
- sputteringParticle ejection from surfaces
micrometeorites · solar wind · Apollo · outgassing · sublimation · lunar dust · transient · collisionless
atmospheres
Gaseous layers surrounding celestial bodies
- ionospheresCharged upper atmospheric regions
- stratospheresAtmospheric layers above weather
- atmospheric layersDistinct altitude zones surrounding Earth
Earth · Mars · Mercury · Venus · hydrogen · helium · rarefied · tenuous · outermost · boundary
orbital mechanics
Science of celestial motion
- dragResistance through fluid
- altitudeMeasured height above reference
- atmospheric reentrySpacecraft returning through air
space stations · ISS · Hubble · collision · debris · tracking · decay · solar activity · mission planning
sodium
Eleventh element, highly reactive
- potassiumNineteenth element, symbol K
- argonUnreactive element eighteen
- regolithFragmented covering over bedrock
sputtering · micrometeorites · solar wind · Apollo · outgassing · sublimation · lunar dust · transient · collisionless · Mercury