Atmosphere of Venus
The atmosphere of Venus is the layer of gases surrounding Venus. It is composed primarily of carbon dioxide and is much denser and hotter than that of Earth. The temperature at the surface is 740 K (467 °C, 872 °F), and the pressure is 93 bar (9.3 MPa), roughly the pressure found underwater on Earth. The Venusian atmosphere supports opaque clouds made of sulfuric acid, making optical Earth-based and orbital observation of the surface impossible. Information about the topography has been obtained exclusively by radar imaging. Aside from carbon dioxide, the other main component is nitrogen. Other chemical compounds are present only in trace amounts.
Vacuum airship
where formula_28 formula_29 and formula_30 formula_31 are pressure and density of standard Earth atmosphere at sea level, formula_32 and formula_33 are molar mass (kg/kmol) and temperature (K) of atmosphere at floating area.
Of all known planets and moons of the Sun system only the Venusian atmosphere has formula_21 big enough to surpass formula_20 for such materials as some composites (below altitude of ca. 15 km) and graphene (below altitude of ca. 40 km). Both materials may survive in the Venusian atmosphere. The equation for formula_21 shows that exoplanets with dense, cold and high-molecular (formula_37, formula_38, formula_39 type) atmospheres may be suitable for vacuum airships, but it is a rare type of atmosphere.