Aircraft flying at similar altitudes inject water vapor into the atmosphere, which condenses quickly as the exhaust hits the very cold air. (drtimball.com)
Biodiversity is often studied on idealized cone - shaped mountains, where similar habitats are assumed to be found at similar altitudes. (sciencedaily.com)
That contrasts sharply with other ephemeral events at similar altitudes, which glimmer into being when electrical current travels upward from lightning clouds at altitudes of about 10 km. (newscientist.com)