Venus is one of the four rocky planets in our solar system. It is getting cold. And today not even a drop of water can flow there. There is no doubt about it. But the planet’s past remains a mystery to researchers. Some imagine the ocean for him. Others claim that Venus never knew the conditions necessary for the formation of such bodies of liquid water. Bordeaux Astrophysics Laboratory researcher Jeremy Leconte takes stock for us.
Today,It is a dry planet. Desert. Yet scientists wonder whether it may not have been able to shelter an ocean in its past. Look a little more like Earth. ” No “, concludes by researchers from CNRS and the University of Versailles Saint-Quentin.
Before explaining how these French scientists got there, it’s good to remember that another study published by American researchers a few years ago conceived. Climate simulations introduced from there, a . with similar to what we know on our Earth, then showed that these oceans evaporate, form Protectors, which reflect sunlight. “In the so-called substellar zone, that is, the point where the Sun is most hot, especially, explains researcher Jeremy LeConte from the laboratory of from Bordeaux. A little bit on the level of what happens on Earth , in short”.
The work of French researchers does not really contradict each other. “Our colleagues show that if oceans did exist on Venus, they would have been able to maintain, emphasizes Jeremy LeConte. We, we wondered if oceans could even be. And our answer is no.”
What are the chances of an ocean forming on Venus?
“When they form, the planets literally cover themselves with an ocean”. a magma that emits a large amount of gas and maintains a very dense atmosphere in which (CO2) and of (NS20). Ale’ is intense, describes us . If the planet cools enough that water vapor condenses and it rains, oceans could form.” This is what has been played out on our earth.
NSWhat French researchers rely on suggests that on Venus, things didn’t quite happen as envisaged by the scenario envisioned by the American study. “The only place on the planet where it wasn’t very hot was on the night side. And moreover, very high in the atmosphere, the side . From Were able to reach there by the day laden with water vapor. Then they formed clouds, but which remained local during the night. Therefore they could not have a protective effect. They could not participate in refreshing Venus. Worse, they created a kind of heat shield that even stopped the planet from cooling down. It could not rain. No ocean could be formed. “
There is little chance that Venus could form an ocean.
“If we imagine that the sea on Venus is like the toss of a coin, the American study just told us that if the coin falls on its shore, it has a good chance of staying there. Very good. But we , we say … that the probability of the coin falling is very small”, Jeremy LeConte continues.
Extract information about other planets
Astrophysicists now want to understand what could be the implications of this study.. They would like to better fix the limits within which water can be . “Knowing that there was never an ocean on Venus gives us a priceless hint, explains Jeremy LeConte. Our work leads us to consider that if our Earth was born around a As our Sun is today, it has never been cold enough to form oceans. Thus, an exoplanet located at the same distance from its star as we are from our star does not necessarily have close oceans. Enough that their star has changed a bit – as is the case , host stars of most known exoplanets – So that this planet can never cool itself enough”.
Answering the question of possible past oceans on Venus could also provide important information about our planet’s future. “Studies have already shown us that Earth can within a billion years” – a period of time that remains to be defined more precisely –, lose your oceans, explains the astrophysicist. In the past, Venus received slightly less energy from the Sun. Because of the nature of our star, which is growingfor a longer period of time. A small fraction of what our planet gets today. In the future, Earth will receive as much energy from the Sun as Venus receives today. Thus, by studying Venus’s past, we can hope to clarify whether and when our planets run the risk of losing their oceans. “
To confirm their results, the French researchers will nonetheless wait for data that can be collected on site by missions that will soon be launched to Venus. “We know that this planet has water vapor in its atmosphere. But surprisingly little. It’s hard to imagine an ocean a few centimeters deep. We believe that at some point in history there was a lot of water in the atmosphere of Venus. But that She fled to space, left far behindto shape this oxidized atmosphere as we know it”, explains Jeremy LeConte.
“One can imagine that new missions to Venus will be able to measure the chemical composition of its atmosphere and even the isotopic composition of some of its elements. with the idea of dating the escape of water. If this happened late in the life of the planet, we can imagine that Venus had an ocean and it evaporated when the Sun was very hot. gone, that’s waterof its environment. If this has happened before, it could be further evidence that Venus was never able to close the ocean. It is these kinds of clues that we have to collect now. “
Veritas Mission (NASA) and( ), for them, will achieve, by , Mineral measurements of the surface of Venus. Although some Water is needed to make it. Detecting their presence would be a strong indication of the permanent presence of liquid water on the planet’s surface. “In this case, we don’t have to explain the stability of the oceans – Remember, this was done by the US study –, but how was water vapor able to condense everything to form it early in the history of Venus?, we have as a conclusion, also tells the researcher Emmanuel Mack of the University of Versailles Saint-Quentin, also the author of the study.
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