Planetary scientists have long speculated that Venus' potential habitability lies not in its hot surface but in a cloud layer at an altitude of 48 to 60 kilometers, where temperatures match those of Earth's surface. However, it is commonly believed that Venusian clouds cannot support life because their chemical composition is concentrated sulfuric acid, a highly aggressive solvent. In the new study, chemists studied 20 biogenic amino acids across a range of sulfuric acid concentrations and temperatures in the Venus cloud. After four weeks, the researchers found that 19 of the biogenic amino acids tested were either unreactive or chemically modified only in their side chains. Their main discovery is that the amino acid backbone remains intact in concentrated sulfuric acid.
This composite image taken by JAXA's Akatsuki spacecraft shows Venus. Image credit: JAXA / ISAS / DARTS / Damia Bouic.
“What is quite surprising is that concentrated sulfuric acid is not a universally hostile solvent for organic chemistry,” said MIT researcher Dr. Janusz Petkowski.
“We found that the building blocks of life on Earth are stable in sulfuric acid, which is very interesting as we consider the possibility of life on Venus,” said Sarah Seager of the Massachusetts Institute of Technology. the professor added.
“That doesn't mean life there will be the same as it is here. In fact, we know it's unlikely. But this study suggests that Venus' clouds support the complex chemicals necessary for life. We advance the idea that there is a possibility that
The search for life in Venus' clouds has gained momentum in recent years, spurred by the detection of the controversial molecule phosphine, a molecule thought to be a signature of life, in the planet's atmosphere. There is.
Although the discovery remains debated, the news reignited old questions about whether life could actually exist on Earth's sister planet.
In search of answers, scientists are planning several missions to Venus. That includes the first largely privately-funded mission to Venus, backed by California-based launch company Rocket Lab.
The mission, for which Professor Seeger is the principal scientist, aims to send a spacecraft into the planet's clouds and analyze their chemistry for signs of organic molecules.
Ahead of the mission's launch in January 2025, Professor Seager and his colleagues will test various materials in concentrated sulfuric acid to find out whether debris from life on Earth might be stable in Venus' clouds. I've been testing molecules. The most acidic place on earth.
“People have a perception that concentrated sulfuric acid is a very aggressive solvent that will tear everything apart, but we are finding that this is not necessarily true,” Dr. Petkowski said.
In fact, the authors have previously shown that complex organic molecules, such as some fatty acids and nucleic acids, are surprisingly stable in sulfuric acid.
They are careful to emphasize, as they do in the current paper, that complex organic chemistry is of course not life, but without organic chemistry there is no life.
In other words, if certain molecules can survive in sulfuric acid, Venus' highly acidic clouds are probably habitable, if not necessarily habitable.
In the new study, researchers focused on 20 biogenic amino acids, amino acids that are essential for all life on Earth.
They dissolved each type of amino acid in a vial of sulfuric acid mixed with water at concentrations of 81% and 98%, representing the range found in Venus' clouds.
They then used a nuclear magnetic resonance spectrometer to analyze the structure of the amino acids in sulfuric acid.
After analyzing each vial several times over a four-week period, they found that the basic molecular structure, or “skeleton,” of 19 of the 20 amino acids was stable and unaltered, even under highly acidic conditions.
“Just because this skeleton was shown to be stable in sulfuric acid does not mean there is life on Venus,” said Dr. Maxwell Seager, a researcher at Worcester Polytechnic Institute.
“But if we had shown that this spine was compromised, there would have been no possibility of life as we know it.”
of study Published in this week's magazine astrobiology.
_____
Maxwell D. Seeger other. Stability of 20 biogenic amino acids in concentrated sulfuric acid: Implications for the habitability of Venusian clouds. astrobiology, published online March 18, 2024. doi: 10.1089/ast.2023.0082
Source: www.sci.news
