In a few years, a fleet of robotic spaceships will descend on Venus and begin exploring the most hostile world in the solar system. One craft will pass through the planet's dense, hot atmosphere. Two others will orbit Venus over thick, acidic clouds. They will then use radar telescopes to view the terrain below.This scrutiny is a sign of a remarkable revival in interest in Earth's closest planetary neighbor. The European and American space agencies have been neglecting Venus for more than a decade. Three new Venus missions were announced in June within days of each others.Hkan Svedhem was the former project manager for Europe's previous probe to Venus Express. He told Nature last week that Venus had been too forgotten for too long.The new missions Nasas Veritas, Davinci+ probes, and Europe's EnVision satellite have a clear goal. They are interested in understanding why the Earth's sibling planet is so different from our world.Astronomers discovered that both planets were the same size, have the same compositions, ages, and orbits around the sun, as they did at the start of the space age in 1960s. It was thought that there might be forests or oceans beneath the thick clouds of Venus. In the 1970s and 1980s, Soviet and American space agencies sent a series robot probes to discover the truth.The ESA's EnVision orbiter will map and record the surface from high up. Photograph by ESA/PAThey showed a hellish world. Venus' surface temperature was 475C. This is enough heat to melt lead. The atmospheric pressure at Venus' surface is 93 bar, which is the equivalent of the atmosphere a kilometre below the ocean. The Soviet probes that arrived on Venus in the 70s or 80s were unable to transmit data for two hours. This was before they succumbed to heat and crushing pressure.Venus was also covered in thick clouds sulphuric acids. Our world, however, has oceans of liquid water and clouds, ice caps, and supports many forms of living creatures on its land, in the seas, and in the sky. Despite their superficial similarities, the differences between these two planets are striking.The vast amount of carbon dioxide on Venus is the main reason for these very different conditions. This has caused solar radiation to be trapped and created a runaway greenhouse effect. It is a magnitude that dwarfs the effects of the climate crisis on Earth, which is causing disruptions in weather patterns and melting ice caps.Scientists are trying to figure out how this carbon dioxide buildup happened. Was Venus just unlucky or did Earth have a lucky break? Are thick carbon dioxide atmospheres a common feature of planets orbiting like Earth and Venus that trap solar radiation and trigger runaway climate effects? Or was this a rare development with Venus?Dense cloud cover obscures the planet's surface. Photograph by NASA/JPL–Caltech/SwRI/MSSS/Gerald Eichstadt/Heidi N. Becker/Koji Kumarura)/PAThese are important questions that have important implications, and not only for understanding how life evolved and appeared on Earth, but also for other areas of science, according to Colin Wilson, a physicist at Oxford University. These questions have important implications for the search for habitable planets orbiting other stars in our galaxy.Astronomers are currently focusing their efforts on finding small rocky planets, such as Earth, that orbit stars at distances in which water is likely exist in liquid form. But, judging from Venus, the only world in our solar system found in this zone, it may not be so promising. This means that if Venus is the norm and Earth the exception, then we may find that these planets offer far less hope for hosting alien life.Giada, the deputy principal investigator of Nasas Davinci+ probe, stressed this point: Our investigation into the evolution of Venus could help us better understand the distribution of habitable worlds elsewhere in the universe and how they evolve over time in general, she stated. It could be, however, that Venus was in the wrong spot. Venus was slightly warmer than the Earth, 67 million miles closer to the sun than the Earth, compared to 93 million miles. This is because it was formed at the solar system birth 4.5 billion year ago. Because of this, water vapour from its atmosphere did not condense into oceans like it did on Earth. Our seas were crucial in absorbing carbon dioxide and preventing runaway greenhouse warming.Another evidence suggests that Venus may have once had liquid water on it's surface and that another event caused the current rampant warming. Three new probes will attempt to discover clues about what these might be. Wilson stated that it will be vital to study the surface of the planets. The US Magellan probe, which was launched to Venus in 1989, used radar to see through the clouds. It gave us a stunning global map of Venus that showed volcanoes and a surface that had been through a lot of turmoil. It was only a snapshot.It is not known if these volcanoes are still in active. New space probes will use 21st century radar technology to map Venus, giving us a more dynamic view of the planet.Nasas Davinci+ is set to descend into the atmosphere. Photograph: NASA GSFC visualization created by CI Labs Michael Lentz, and other photographersJane Greaves, an astronomer from Cardiff University, supported this point. Although some instruments such as radars and mass spectrometers have been used in the past to study Venus, their technology is much more advanced and better today. This will allow us to identify more molecules and probe deeper.Nasas Veritas, the European Space Agency's EnVision and Nasas Veritas will both be involved in mapping Venus' surface from orbit high above its acid cloud clouds. Davinci+, on the other hand, will be carrying a small probe to Venus that it will release. It will then parachute down through its atmosphere and sample its components every 100 meters as it descends. These measurements will help us understand the origins and evolution of Venus' atmosphere.By studying the levels of deuterium (an isotope hydrogen), it will be possible to determine the amount of water on Venus. Additionally, scientists may be able to analyze noble gases like argon or neon in the atmosphere to determine if Venus once had liquid water. This information could be vital in helping to provide clues as to Venus' path to the dark side.It's amazing how little we know about Venus," said Tom Wagner, a scientist at Nasas Discovery Program.These missions combined will reveal a lot about the planet, from its clouds and volcanoes to its core. It will feel as if the planet has been rediscovered.
