NASA continues to be perplexed by tremendously interesting discoveries. Now it’s the turn of Titan, Saturn’s moon. This is a molecule key to life, and one that has never been seen interacting in the way it does. Apparently, these molecules, supposedly essentially incompatible, could combine to form solids never before seen in the Solar System, according to a recent study.
The discovery about Saturn’s moon Titan has challenged what scientists considered a basic rule of chemistry
“Life can arise under conditions we never thought possible,” the study’s authors note. The discovery about Saturn’s moon Titan has challenged what scientists considered a basic rule of chemistry. The finding, published in the Proceedings of the National Academy of Sciences (PNAS), reveals that on Titan, hydrogen cyanide (HCN) can combine with gases such as methane or ethane to form solid, stable structures. This extraterrestrial matter is likely abundant on Titan, according to a team led by chemist Fernando Izquierdo-Ruiz of Chalmers University of Technology in Sweden.
This study has discovered that what is impossible to unite on Earth due to environmental conditions actually does. It’s similar to how water and oil in space can coexist, uniting what on Earth would otherwise be kept separate by the extreme cold. As a general rule, polar and nonpolar molecules, such as methane and ethane on Titan, tend to repel each other. It takes more energy to unite them than to separate them. “These findings are very exciting and may help us understand something on a large scale: a moon (Titan) as large as the planet Mercury,” says chemist Martin Rahm of Chalmers University of Technology.
Research: combined HCN with methane and ethane, observed changes in their vibrational modes
The observations began at NASA. Specifically, the investigation into the probable behavior of hydrogen cyanide on Titan began with scientists at NASA’s Jet Propulsion Laboratory, who sought to understand what happens after the molecule forms in Titan’s atmosphere. Now, in the experiment at hand, Rahm’s team combined HCN with methane and ethane, observed changes in their vibrational modes, and verified through simulations that these “co-crystals” could form and sustain themselves under Titan’s conditions, i.e., extreme cold. The experiment was conducted at temperatures of approximately -180 degrees Celsius (-292 Fahrenheit), creating an environment typical of Titan.
We can say that if chemistry can behave in more flexible ways, it changes the way we conceive certain things
This experiment is highly relevant because it provides insight into how certain molecules behave in other types of environments, specifically extreme states. HCN is a key molecule in origin-of-life experiments: it is considered a precursor to nucleobases and amino acids. “The question we asked ourselves was a bit of a crazy one: Can the measurements be explained by a crystal structure in which methane or ethane are mixed with hydrogen cyanide? This contradicts the chemical rule that ‘like dissolves like,'” Rahm explained at the start of the investigation. “If on Titan or other icy worlds, HCN can mix with hydrocarbons in unexpected ways, it suggests that ‘pre-life chemistry’ could behave completely differently than previously understood.”
The results imply that the surface of Titan’s icy lakes could contain compounds whose combinations we hadn’t considered. Small but distinct changes were recorded in the oscillations of hydrogen cyanide after exposure to methane and ethane, indicating that these incompatible substances were not just together, but interacting. Narrowing down the explanations a great deal, we can say that if chemistry can behave in more flexible ways, it changes the way we conceive of where and how life might originate. Hence the importance of this type of research and scientific discoveries.
