Venus: the veiled planet

Abstract

• When visible, Venus is the brightest planet in the sky. It orbits the Sun inside Earth's orbit, appearing in the evening or morning hours and never in the middle of the night. • No human eye has ever gazed on the surface of Venus, which is forever hidden by a thick overcast of impenetrable clouds. • Venera spacecraft have parachuted through the clouds of Venus, surviving long enough to measure the properties of its torrid surface and even photographing it. • The deadly efficient greenhouse effect of a thick, carbon-dioxide atmosphere has scorched Venus's surface, raising its temperature to 735 kelvin, even hotter than Mercury's average dayside temperature. • In size, density and composition, Venus is almost identical to the Earth, but radar signals and space probes have penetrated its clouds to reveal an unearthly surface without a trace of liquid water or life. • The pale yellow clouds of Venus are composed of concentrated sulfuric-acid droplets. • The surface of Venus lies under a crushing atmosphere whose surface pressure is 92 times that on Earth. • It takes only 4 Earth days for the high-flying clouds to move once about Venus, from east to west, blown by fierce, rapid winds, but the slow winds near the surface rotate with the planet, once every 243 Earth days in the same backwards, retrograde direction. • The high, rapid winds on Venus spiral toward its poles, producing a huge, whirling polar vortex at both poles of the planet. […]