Science & Technology (Commonwealth Union) – Venus has historically been an astronomical fascination even among non-astronomers. The planet is known to be entirely covered in a permanent layer of clouds.
The clouds from Venus contain roughly 98 percent sulfuric acid, an environment long considered far too hostile for complex biological molecules to endure. Recent research conducted by scientists at the Massachusetts Institute of Technology (MIT), however, challenges that assumption. The team has found that short chains of amino acids known as peptides can remain intact in highly concentrated sulfuric acid and can also fold into distinct structures that could potentially support biological activity.
MIT chemistry professor and study senior author Mei Hong found that peptides capable of reaching Venus’ highly concentrated sulfuric acid cloud layer could potentially persist there, remaining stable and protected within the droplets. And as soon as these macromolecules have a defined 3D structure, they may possibly have activity.
In many previous attempts going decades back to determine the possibility of life on other planets, the presence of water and oxygen was a key determining factor.
The results indicate that the search for extraterrestrial life may need to extend beyond planets that closely resemble Earth. Sara Seager, from the Class of 1941 Professor of Planetary Sciences at MIT, stated that researchers should remain open to the possibility that life could emerge or persist in environments radically different from those found on our planet.
Seager, a senior author of the research, noted that scientists still have much to learn about the wide variety of planetary environments that may exist beyond our solar system. While researchers often search for exoplanets that closely resemble Earth, she pointed out that many of the worlds they encounter could instead have characteristics similar to Venus. The study’s findings, she said, broaden the range of environments that scientists should consider when investigating potentially habitable planets.
Janusz Petkowski, a research assistant professor at Wroclaw University of Science and Technology, is also listed as a senior author of the study
. The study, published this week in the Proceedings of the National Academy of Sciences, is led by Jia Yi Zhang, an MIT graduate student. Aurelio Dregni, a former postdoctoral researcher at MIT, also contributed to the work.
Although Venus has a surface environment far too hot to support life as we know it, conditions in its atmosphere are considerably more moderate. Its cloud layer, located roughly 30 to 40 miles above the surface, has temperatures that could potentially be compatible with life. However, these clouds consist of sulfuric acid droplets, an extremely corrosive substance capable of dissolving metals and breaking down most biological molecules found on Earth.
Meteorites carrying peptide-forming compounds frequently pass into Venus’s atmosphere. This raises the possibility that these compounds could provide the raw materials needed for primitive life—provided they can withstand the highly corrosive conditions within the clouds.
Seager’s group began a series of experiments in 2020 to test whether different biological molecules could be stable in such highly acidic environments. Researchers at MIT’s Department of Chemistry Instrumentation Facility (DCIF) investigated how different compounds behave in an extremely acidic environment, dissolving them in almost pure sulfuric acid for analysis. They used nuclear magnetic resonance (NMR) spectroscopy to study the compounds at the molecular level. By detecting the magnetic behavior of atomic nuclei within molecules, the technique provides researchers with information about molecular structure and helps reveal how these compounds are arranged and maintained under such harsh conditions.
Previous work has already demonstrated that nucleic acids, the molecules that make up DNA, can survive in very acidic environments. Lipids and amino acids also seemed capable of living in these conditions. Then the scientist shifted their attention to peptides, short chains of amino acids, to make a determination if there was a possibility not just to survive this acidity.
Because this posed a particularly difficult experimental challenge, researchers at DCIF recommended that Seager collaborate with Hong, an NMR specialist whose laboratory houses a sophisticated 800-megahertz solution NMR spectrometer.
