The habitable or infernal planet Venus in the past: astronomers make a discovery

Contrary to what is often believed, Venus is not strictly too close to the Sun to prohibit the presence of liquid water on its surface. Moreover, if we only take into account the light received from our star without considering its atmosphere, its temperature would be -46°C, its ground reflecting radiation twice as well as that of the Earth.

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Finally, global warming for which humans are not responsible!

Venus' current problem is its atmosphere filled with carbon dioxide and sulfur — consider that it rains sulfuric acid at high altitudes. The resulting hellish greenhouse effect leads to the highest surface temperature in the entire Solar System, measured at 460°C. For once, it's not our fault, we A wise man is wise.

But as we have seen, it is not directly its proximity to the Sun that is in question. The planet Venus is indeed in the so-called habitable zone of its star, that is to say that nothing in its orbit prohibits that at one time or another in its history, it could have had a more lenient atmosphere and water, even oceans. Nothing, really?

In fact, according to this study published on Natureby studying the current atmosphere of Venus it is possible to deduce its history and its past components. Here is a schematic presentation of the two scenarios envisaged for the evolution of the planet.

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Today, the atmosphere of Venus is saturated with gases that are thought to come from its extremely active volcanism in the probably fairly recent past. But because a planet's interior and its atmosphere are linked by a certain dynamic, one informs scientists about the other.

So the chemistry of the atmosphere is the key here. If Venus had oceans, then a significant part of this water should still be found inside the planet and appear in the degassing caused by its numerous volcanic eruptions (remember that Venus has “pancakes” of soft and viscous lava on its surface). But here is what the authors of the article say: “Venusian volcanic gases have at most a soft water fraction of 6%, which is significantly drier than terrestrial magmas degassed at similar conditions.”

The goddess of love and beauty is dry inside

This very weakly aqueous degassing is therefore a sign of an interior that is very poor in water. Yes, Venus is dry in her bowels! This study comes some time after the validation by NASA of the two projects Da Vinci and Veritas, which are intended to study the atmosphere of our close neighbor. It is also a valuable indicator in the search for extraterrestrial life for at least two reasons:

• If Venus had benefited from the conditions for life to develop there, namely liquid water on the surface in a stable and lasting manner, we would have had three habitable planets in our solar system. Discovering past traces of life there would therefore be a very strong indicator of biological presence elsewhere in the Galaxy.

• If this study is correct and Venus has never been suitable for life, then we could perhaps eliminate from our search for habitable exoplanets those orbiting in the inner limit of their star's habitable zone. This would free up valuable atmospheric observation time for the James Webb Space Telescope.