The planet Venus is a hell wrapped in a thick layer of carbon dioxide and sulfuric acid, where the surface can reach temperatures of 400ºC. Conditions impossible for life. But, what was always so? Forty years ago, the Pioneer mission NASA found strong evidence that this "evil brother" of the Earth may have had once an ocean of liquid shallow. Now, two researchers at the Goddard Institute of Space Science have developed five simulations assuming different levels of water coverage to see to what extent that world neighbor could be much more friendly than the current, maybe even a twin of our own.
In the five scenarios, they discovered that Venus was able to maintain stable temperatures between a maximum of 50 ° C and a minimum of 20º C for about 3,000 million years. It could even have remained a temperate climate on Venus today if it had not been a series of events that caused a release of carbon dioxide stored in rocks of the earth makes approximately 700-750 million years ago.
"Our hypothesis is that Venus may have had a stable climate over billions of years . It is possible that an event of reform almost global is responsible for his transformation from a climate similar to that of the Earth from the hellish emissions that we see today", says Michael Way, of the Goddard Institute, who has presented his findings at a meeting astrónomica held these days in Geneva, Switzerland.
deep Ocean
Three of the five scenarios studied by the researchers assumed the topography of Venus as we see it today and felt a deep ocean with an average of 310 meters, a layer of shallow water with an average of 10 meters and a small amount of water locked in the soil. By way of comparison, also included a scenario with the topography of the Land, and an ocean of 310 metres and, finally, a world completely covered by an ocean of 158 meters deep.
in order To simulate the environmental conditions makes some 4,200 million years ago, 715 million years ago and today, the researchers adapted a model of the general circulation in 3D to account for the increase of the solar radiation as our Sun has warmed during its useful life, as well as changes in the atmospheric compositions.
Although many researchers believe that Venus is beyond the inner boundary of the habitable zone of our Solar System and is too close to the Sun to support liquid water, the new study suggests that this might not be the case.
"Venus currently has almost double the amount of solar radiation that we have on Earth. However, in all of the scenarios that we modeled, we found that Venus could still withstand surface temperatures amenable to liquid water," said Way.
greenhouse Effect runawayMakes about 4,200 million years ago, shortly after its formation, Venus would have completed a period of rapid cooling and its atmosphere would have been dominated by carbon dioxide. If the planet evolved in a similar way to the Earth in the next 3,000 million years, the carbon dioxide would have been dragged through rocks of silicate and locked in the surface. In the second period, modeled ago, 715 million years ago, the atmosphere probably would have been dominated by nitrogen with traces of carbon dioxide and methane, similar to the present Earth, and these conditions might have remained stable until today.
The cause of the gas release that led to the dramatic transformation of Venus is a mystery, although it is probably related to the volcanic activity of the planet. One possibility is that large amounts of magma burbujearon, releasing carbon dioxide in the molten rocks into the atmosphere. The magma solidified before reaching the surface and this created a barrier which meant that the gas could not resorb. The presence of large amounts of carbon dioxide triggered a greenhouse effect runaway, which has resulted in the searing average temperature of 462º that is today on Venus.
"Something happened on Venus, where it released a large amount of gas to the atmosphere and the rocks, they were not able to absorb it. On Earth, we have some examples of degassing on a large scale, for example, the creation of the traps siberian 500 million years ago, which is linked to a mass extinction, but nothing to this scale. Completely transformed Venus," says Way.
More questsAccording to the authors, there are still two unknowns important that need to be addressed before the question of whether Venus could have been habitable to be able to respond completely. The first relates to the speed with which Venus is cooled initially, and if he was able to condense liquid water on its surface in the first place. The second question is whether the global event that changed the face was unique, or simply the last of a series of events that go back thousands of millions of years in the history of Venus.
"we Need more missions to study Venus, and to obtain a more detailed understanding of its history and evolution," says Way. "However, our models show that there is a real possibility that Venus could have been habitable, and radically different from what we see today. This opens up all sorts of implications for the exoplanets that are in the call 'Venus Zone ', that it can indeed host liquid water and temperate climates".
Date Of Update: 24 September 2019, 05:01
