it really depends on how low one wants to set the bar for what's considered "atmosphere" - there's a cloud of our atmosphere extending out beyond the moon's orbit, its just really, really thin. low earth orbit is inside of it, geostationary orbit is inside of it, its a blob that connects the moon and the earth. its just a really, really diffuse blob that extends out that far. but its definitely much more dense than interplanetary space outside of it.
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