Venus does not have enough water in the clouds to sustain life

In 1978, NASA launched the Pioneer Venus mission, which consists of an orbiter and a set of four small probes dumped into the atmosphere of Venus. Within the atmosphere are signs of deuterium – a heavy isotope of hydrogen that can result from the breakdown of water. Scientists wondered whether Venus was once home to greater amounts of water, and whether some of it actually got stuck in larger amounts in the atmosphere.

Fast forward to 2020 and the potential discovery of Effects of phosphine in the atmosphere of Venus. These scholars I thought of a scenario To find out how a possible water cycle in the thick clouds of sulfuric acid on Venus could allow microbes on Venus to reside in droplets at high altitudes and produce spores that can hydrate and keep the reproductive life cycle going. Although the surface of the planet is from hell, its clouds are stable and milder.

Well, the new paper means that this is highly unlikely. The study focuses on “hydroactivity,” or the amount of water available for microorganisms to use, which is measured on a scale of 0 to 1. For this study, the research team sought to measure water activity in clouds by calculating atmospheric ratios. Humidity (the amount of water that saturates the air at a given temperature). Use the scientists Aspergillus penicillium, A fungus capable of surviving in the driest conditions imaginable, as a baseline for understanding how much water scarcity an organism can tolerate while still running its metabolic and reproductive functions. The answer is a water activity score of 0.585 – the actual “life limit” of biological activity as we know it.

Using atmospheric data collected from previous Venus missions and using newer models for how water activity is assessed, Halsworth and his team calculated the water activity of Venus’ clouds at altitudes of 68-42 kilometers, where life-sustaining temperatures range from -40 degrees Celsius to 130 Celsius. Celsius. They find that the water activity is, at best, 0.004. “The most drought-tolerant microbes on Earth wouldn’t stand a chance on Venus,” Hallsworth says.

The researchers also point out that even if the activity of the water itself is higher, the atmosphere of Venus is saturated with hostile elements that are likely to hinder cellular systems from working properly (for example, sulfuric acid cells).

The other planets were doing better. The team also calculated water activity in Martian clouds to be 0.537 (comparable to Earth’s stratosphere, and only SMIDGE below the “life limit” for life on Earth), and in Jupiter’s clouds to be at least 0.585 at locations where the temperature is between -10°C and 40 degrees Celsius. “We can’t say that Jupiter’s clouds are habitable,” says Christopher McKay, a NASA scientist and one of the study’s authors. “We can say it’s not restricted by aquatic activity.”

The results need to be confirmed by further study, but the authors are pretty confident that it won’t change, even with Two new missions for NASA A new European Space Agency mission headed to Venus towards the end of the decade.

Of course, there are some caveats. “We have to base our discussions of life on other worlds on what we know about life on Earth, because we have a basis for it,” McKay says. “But part of me hopes that when we find life elsewhere, it’s really very different,” with biochemistry working beyond the limits of what we’ve seen here on Earth.

And while current life on Venus may seem improbable with these new discoveries, that doesn’t mean Venus has always been barren. There is a whole hidden history of the planet that scientists want to investigate.

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