The supposed discovery of phosphine in the atmosphere of Venus raised the question of whether it was of biological origin.
Given how cruel Venus is to life as we know it, the question has caused quite a stir, but scientists have now decided that the flaming planet could indeed be habitable, high in the clouds, far from the scorching planet's surface.
The possibility of the existence of photosynthetic organisms
Specifically, the level of solar radiation at certain altitudes is comparable to solar radiation on Earth, meaning that airborne microbes that perform photosynthesis can survive at those altitudes.
In addition, the thick layer of clouds provides some protection from harmful UV rays, and the acidity in these clouds is likely to be lower than expected and within acceptable parameters for life.
Photophysical and chemical considerations support the possibility of phototrophic organisms on Venus (NASA)
"These photophysical and chemical considerations together support the possibility of phototrophic organisms in the clouds of Venus," the researchers wrote in their paper, published in Astrobiology on September 27, 2021.
But, when it comes to the possibility of hosting life, Venus seems unlikely, conditions on the surface are truly hell-like;
The planet is completely surrounded by a dense atmosphere made up of almost only carbon dioxide, which rotates 60 times faster than the planet itself, producing strong winds.
The sky is also filled with thick clouds of sulfuric acid, and its atmospheric pressure at zero altitude is close to 100 times greater than Earth's pressure, and if that's not bad enough, it is extremely hot, with an average surface temperature of 471 degrees Celsius.
Therefore, when astronomers announced that they had discovered phosphine gas in the atmosphere of the planet last year, a wide debate ensued, and this is because one of the explanations for its existence could be the presence of microorganisms.
Photosynthesis could be possible in the clouds of Venus (American press)
Where is phosphine found?
Phosphine can be found here on Earth in limited cases, one of which is anaerobic or low-oxygen ecosystems, which are found in swamps and sludge, where anaerobic microbes thrive, are found in gut and gut gases, somehow anaerobic microorganisms produce phosphine, and Venus clouds anaerobic;
But biological origin is not the only explanation;
A volcanic origin is also possible, but in order to assess the probability of a biological origin in the first place, a correct analysis of the viability of Venus would certainly be a major challenge.
Therefore, a team of scientists conducted the following analysis, led by biochemist Rakesh Mogul from Cal Poly Pomona, and the official statement of the university stated:
First, they examined the level of sunlight that can penetrate the clouds of Venus. Scientists had data from Russia's expedition to Venus between 1967 and 1983;
None of its probes survived long on the surface, but they recorded the measurements they took of the clouds as they descended.
With these and other historical measurements, the researchers were able to calculate the levels of light within the clouds, and found that the radiation in the middle and lower clouds of Venus is similar to that found on Earth's surface, where photosynthetic life is abundant.
There is not enough water activity in the clouds of Venus to support life as we know it (American press)
New estimates
But light levels alone are not enough. A study earlier this year found that there isn't enough water activity in Venus's clouds to support life as we know it, but this may not be the case if Venus' clouds are not as we think. Current estimates indicate that the concentration of sulfuric acid is 75% for the middle clouds and 98% for the lower clouds.
Mogul and his international team re-examined the data for Venus, and found that the signs indicating sulfuric acid could also be caused by equivalent forms of sulfuric acid, such as ammonium bisulfate. Much lower - in the clouds of Venus than previously estimated.
This is not to say that this is the case, but the research aims simply to prove that this is possible, opening up avenues for future research, including more detailed analysis of Venus's atmosphere, to determine habitability.
"Our study provides significant support for the potential for phototrophic and/or chemical feeding by microorganisms in the clouds of Venus," Mogul says. The limited ultraviolet rays indicate that the clouds of Venus could be suitable for life."
So, "we think Venus' clouds would be a great target for life-sustaining or life-detecting missions, such as those currently planned for Mars and Europa."