Image: The Magellan probe precisely mapped the surface of Venus using radar altimeters working at wavelengths at which Venusian clouds are transparent. This made it possible to reconstruct the relief of the planet by computer in synthetic images.
Credit: E. De Jong et al. (JPL), MIPL, Magellan Team, NASA.
Venus suffers from an intense greenhouse effect, its sky is permanently overcast, it seems to have been entirely covered by volcanic lava. These characteristics make Venus a fascinating and extremely inhospitable planet, with a hellish climate and extreme conditions that set it apart from other terrestrial planets in the solar system.
The extreme greenhouse effect: Venus has the densest atmosphere of all the terrestrial planets in the solar system. This dense atmosphere is composed mainly of carbon dioxide (CO2), with traces of gases such as nitrogen and sulfur. The resulting greenhouse effect is so intense that it has caused an extreme greenhouse phenomenon, making Venus the hottest planet in the solar system, with an average surface temperature of around 470°C (878°F ), hotter than Mercury despite its proximity to the Sun.
Crushing Atmospheric Pressure: Due to its dense atmosphere, the atmospheric pressure on the surface of Venus is extremely high, reaching approximately 92 times that of Earth. This is equivalent to the pressure one would feel at a depth of about 1 km under the ocean on Earth.
Slow retrograde rotation: Unlike most planets in the solar system, Venus has a retrograde rotation, that is to say it rotates in the opposite direction of its revolution around the Sun. In addition, its rotation is exceptionally slow, with a rotation period of almost 243 Earth days, which means Venusian days are longer than its years.
Thick layer of clouds: The cloud layer of Venus is thick and composed mainly of sulfuric acid. These clouds are so dense that they completely envelop the planet, preventing any direct observation of its surface from space.
Super-rotation phenomenon: The winds in the atmosphere of Venus move extremely quickly, creating a super-rotation phenomenon. Atmospheric winds can reach speeds of up to 360 km/h (225 mph), much faster than the rotation of the planet itself.
Volcanic Landform: The surface of Venus is marked by vast volcanoes and extensive volcanic plains. The volcanoes of Venus are among the largest in the solar system, with shield volcanoes spanning hundreds of kilometres. In addition, the surface is poorly cratered, the density of meteorite impacts is the same over the entire surface of the planet. Which means that the craters are less than 500 million years old, the trace of the old craters has been erased. This proves that there was significant volcanic activity about 500 million years ago. No smoking cone was observed, it seems that there is no volcanic activity today. All the reliefs, apart from the Mount Maxwell relief, have women's names (Eve, Helen, Cleopatra, Ishtar, Leda, Aphrodite, Diana, Innini (Babylonian fertility goddess)...).
Between 1961 and 1983: The series of 18 Venera missions (Soviet Union) was launched by the Soviet Union to explore Venus. These missions included landers and probes that transmitted data about Venus' atmosphere, surface, and climate. The Venera missions enabled the first successful landings on another planet.
1962: The Mariner 2 probe, launched by NASA, successfully flew past Venus on December 14, 1962, becoming the first mission to achieve a close encounter with another planet. She performed a flyby of the planet, collecting data on the atmosphere and surface temperature. However, the first mission to successfully land on Venus was carried out by the Soviet Union with the Venera 7 mission in 1970.
1978: The Pioneer Venus mission (USA) was launched in 1978 by NASA. It included two probes, an atmospheric probe which entered the atmosphere of Venus and an orbital probe which studied the atmosphere, clouds and geological features of the planet.
1989: NASA's Magellan mission (USA) was an orbital probe that mapped almost entirely the surface of Venus using radar techniques. She provided detailed images of Venus' topography, mountains, volcanoes and craters.
2005: The European Space Agency's Venus Express mission was designed to study the atmosphere and climate of Venus. The orbiting probe collected data on atmospheric composition, winds, clouds and surface features.
2010: The Japan Aerospace Exploration Agency (JAXA) mission, the Akatsuki mission was an orbital probe to study the atmosphere and climate of Venus. It provided detailed observations of the planet's atmospheric dynamics and weather phenomena.