Atmosphere of Venus
In 1761, Russian polymath Mikhail Lomonosov observed an arc of light surrounding the part of Venus off the Sun's disc at the beginning of the egress phase of the transit and concluded that Venus has an atmosphere. In 1940, Rupert Wildt calculated that the amount of CO in the Venusian atmosphere would raise surface temperature above the boiling point for water. This was confirmed when Mariner 2 made radiometer measurements of the temperature in 1962. In 1967, Venera 4 confirmed that the atmosphere consisted primarily of carbon dioxide.
Tholin
Titan tholins are nitrogen-rich organic substances produced by the irradiation of the gaseous mixtures of nitrogen and methane found in the atmosphere and surface of Titan. Titan's atmosphere is about 97% nitrogen, 2.7±0.1% methane and the remaining trace amounts of other gases. In the case of Titan, the haze and orange-red color of its atmosphere is thought to be caused by the presence of tholins.