Above the dense CO2 layer are thick clouds consisting mainly of sulfur dioxide and sulfuric acid droplets.[50][51] These clouds reflect and scatter about 90% of the sunlight that falls on them back into space, and prevent visual observation of the Venusian surface. The permanent cloud cover means that although Venus is closer than Earth to the Sun, the Venusian surface is not as well lit. Strong 300 km/h (190 mph) winds at the cloud tops circle the planet about every four to five earth days.[52] Venusian winds move at up to 60 times the speed of the planet's rotation, while Earth's fastest winds are only 10–20% rotation speed.[53]
The surface of Venus is effectively isothermal; it retains a constant temperature not only between day and night but between the equator and the poles.[2][54] The planet's minute axial tilt—less than 3°, compared to 23° on Earth—also minimizes seasonal temperature variation.[55] The only appreciable variation in temperature occurs with altitude. In 1995, the Magellan probe imaged a highly reflective substance at the tops of the highest mountain peaks that bore a strong resemblance to terrestrial snow. This substance arguably formed from a similar process to snow, albeit at a far higher temperature. Too volatile to condense on the surface, it rose in gas form to cooler higher elevations, where it then fell as precipitation. The identity of this substance is not known with certainty, but speculation has ranged from elemental tellurium to lead sulfide (galena).[56]
The clouds of Venus are capable of producing lightning much like the clouds on Earth.[57] The existence of lightning had been controversial since the first suspected bursts were detected by the Soviet Venera probes. In 2006–07 Venus Express clearly detected whistler mode waves, the signatures of lightning. Their intermittent appearance indicates a pattern associated with weather activity. The lightning rate is at least half of that on Earth.[57] In 2007 the Venus Express probe discovered that a huge double atmospheric vortex exists at the south pole of the planet.[58][59]
Another discovery made by the Venus Express probe in 2011 is that an ozone layer exists high in the atmosphere of Venus.[60]
On January 29, 2013, ESA scientists reported that the ionosphere of the planet Venus streams outwards in a manner similar to "the ion tail seen streaming from a comet under similar conditions
The surface of Venus is effectively isothermal; it retains a constant temperature not only between day and night but between the equator and the poles.[2][54] The planet's minute axial tilt—less than 3°, compared to 23° on Earth—also minimizes seasonal temperature variation.[55] The only appreciable variation in temperature occurs with altitude. In 1995, the Magellan probe imaged a highly reflective substance at the tops of the highest mountain peaks that bore a strong resemblance to terrestrial snow. This substance arguably formed from a similar process to snow, albeit at a far higher temperature. Too volatile to condense on the surface, it rose in gas form to cooler higher elevations, where it then fell as precipitation. The identity of this substance is not known with certainty, but speculation has ranged from elemental tellurium to lead sulfide (galena).[56]
The clouds of Venus are capable of producing lightning much like the clouds on Earth.[57] The existence of lightning had been controversial since the first suspected bursts were detected by the Soviet Venera probes. In 2006–07 Venus Express clearly detected whistler mode waves, the signatures of lightning. Their intermittent appearance indicates a pattern associated with weather activity. The lightning rate is at least half of that on Earth.[57] In 2007 the Venus Express probe discovered that a huge double atmospheric vortex exists at the south pole of the planet.[58][59]
Another discovery made by the Venus Express probe in 2011 is that an ozone layer exists high in the atmosphere of Venus.[60]
On January 29, 2013, ESA scientists reported that the ionosphere of the planet Venus streams outwards in a manner similar to "the ion tail seen streaming from a comet under similar conditions
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