exosphere
Outermost atmospheric layer
The exosphere is the outermost layer of Earth's atmosphere, where air molecules are so sparse they rarely collide and can escape into space.
It begins roughly 300 miles above the surface and has no clear upper boundary—it simply fades into the vacuum of space.
Other planets with atmospheres also have exospheres.
Lightest noble gas
- hydrogenSimplest atomic element
- oxygenElement eight, colorless gas
- nitrogenElement seven, colorless gas
- rarifiedExclusive, elevated, thin
tenuous · sparse · attenuated · dilute · low density
High-temperature atmospheric zone
- mesosphereAtmospheric layer, 50-85km up
- stratosphereSecond atmospheric layer up
- troposphereLowest atmospheric layer
- ionosphereCharged upper atmospheric layer
Speed to overcome gravity
- solar windContinuous stellar particle emission
- gravity wellRegion of curved spacetime
Orbiting celestial body
- orbitCurved celestial path
- geostationaryFixed above one point
- ISSOrbiting multinational research facility
- HubbleRenowned astronomer's surname
Sputnik · spacecraft · space station · telemetry · remote sensing · weather satellite · communications satellite
Speed to overcome gravity
- outer edgeBounding line of something
- transition zoneRegion between differing areas
helium
Lightest noble gas
- hydrogenSimplest atomic element
- oxygenElement eight, colorless gas
- nitrogenElement seven, colorless gas
rarified · tenuous · sparse · attenuated · dilute · low density
thermosphere
High-temperature atmospheric zone
- mesosphereAtmospheric layer, 50-85km up
- stratosphereSecond atmospheric layer up
- troposphereLowest atmospheric layer
ionosphere · magnetosphere · upper atmosphere · atmospheric layers
escape velocity
Speed to overcome gravity
- solar windContinuous stellar particle emission
- gravity wellRegion of curved spacetime
satellite
Orbiting celestial body
- orbitCurved celestial path
- geostationaryFixed above one point
- ISSOrbiting multinational research facility
Hubble · Sputnik · spacecraft · space station · telemetry · remote sensing · weather satellite · communications satellite
escape velocity
Speed to overcome gravity
- outer edgeBounding line of something
- transition zoneRegion between differing areas
- atmosphereair, humidity, atmosphere, temperature, oxygen
- spacespace, sun, moon, stars, star
- earth scienceatmosphere, earthquake, geology, volcano, crust
- "Exo-" wordsexosuit, exobiology, exocytosis, exotoxin, exomoon
- Inner Planetssurface, atmosphere, orbit, core, mantle
- planetary atmospheresatmospheric layers, clouds, nitrogen, carbon dioxide, argon
exospheretroposphere
Lowest atmospheric layer
ground level · sea level · lower atmosphere · stratosphere · mesosphere
exosphereground
Solid surface underfoot
sea level · subsurface · lithosphere · crust · biosphere
sphere, exoskeleton, exoplanet, exogamy, exothermic, exoteric, exogenous, exoskeletal