Relevant graph for reference: https://en.wikipedia.org/wiki/Atmospheric_window#/media/File:Atmospheric_Transmission.svg https://en.wikipedia.org/wiki/Atmospher

Relevant graph for reference: https://en.wikipedia.org/wiki/Atmospheric_window#/media/File:Atmospheric_Transmission.svg https://en.wikipedia.org/wiki/Atmospheric_window#/media/File... The terrestrial blackbody curves are in the top right (labelled "210 K - 310 K"), and the filled blue curve below those is radiative emission with atmospheric absorption subtracted out. - "Within the mid-infrared range, which is where heat radiation from typical earthbound objects is concentrated, the most applicable atmospheric transmission band is in the 8- to 13-micrometer-wavelength range."