> helium can also leak irrecoverably out the atmosphere. Won't all atmospheric helium be lost to space? See https://en.wikipedia.org/wiki/Atmospheric_escape#/m

> helium can also leak irrecoverably out the atmosphere. Won't all atmospheric helium be lost to space? See https://en.wikipedia.org/wiki/Atmospheric_escape#/media/File:Solar_system_escape_velocity_vs_surface_temperature.svg https://en.wikipedia.org/wiki/Atmospheric_escape#/media/File... Jupiter, Saturn, Uranus, and Neptune are the only planets that can retain helium, AFAIU.