Scientists have recently discovered that in the extremely cold environment of Saturn's largest moon, Titan, materials that were originally unmixable can actually be combined together. This breakthrough provides new clues to understanding the formation process of life's basic molecules.

Titan has long attracted scientific attention due to its complex chemical reactions and icy environment. Titan has lakes, oceans, sand dunes, and a dense atmosphere composed of nitrogen, methane, and complex carbon-based compounds. Due to its many similarities with the early Earth's environment, Titan is considered one of the important targets for exploring the origin of life.

Research by Martin Rahm, associate professor at the Department of Chemistry and Chemical Engineering at Chalmers University of Technology, and his team shows that methane, ethane and hydrogen cyanide, which are abundant on Titan's surface and atmosphere, can interact at extremely low temperatures. The most surprising thing is that the polar molecule hydrogen cyanide can form solid crystals with non-polar molecules such as methane or ethane. Conventional chemistry theory holds that these substances are similar to oil and water and cannot be mixed, but unexpected combinations occurred in Titan's extreme environment.

Professor Rahm pointed out: "This discovery helps us understand large-scale phenomena on giant satellites that are completely different from the Earth, and also paves the way for future lunar research." He also added, "Hydrogen cyanide can participate in the synthesis of basic building blocks of life such as amino acids and nucleoside bases under non-living conditions. Therefore, this study helps reveal the chemical processes before the emergence of life and deepens our understanding of molecular behavior in extreme environments."

The research was carried out by Chalmers University in collaboration with NASA's Jet Propulsion Laboratory. The NASA team mixed hydrogen cyanide with methane or ethane at about 90 Kelvin (about -180°C) and found through laser spectroscopic analysis that although the main frame of the molecule did not change, a new synergy appeared at the atomic level. Rahm's team then used computer simulations to test thousands of solid-state molecular arrangement schemes, confirming that hydride could be embedded into the hydrogen cyanide crystal structure and form a stable new co-crystal. The simulation results are highly consistent with NASA experimental spectral observations, thus validating this finding.

Professor Rahm emphasized that although this result challenges the basic rule of chemistry that "polar and non-polar substances cannot be mixed", it does not require revision of textbooks. "It just proves that the boundaries of chemistry can be expanded and shows that universal rules do not apply in all extreme cases."

NASA plans to launch the Dragonfly probe in 2028 and is expected to arrive at Titan in 2034 to conduct more in-depth chemistry and cutting-edge research on life on its surface. Rahm's team will also continue to work with NASA to further explore the chemical process of hydrogen cyanide in Titan's environment.

Titan not only has the second liquid lake system outside the Earth, but also has a thick atmosphere and seasonal cycles similar to those of the early Earth. It may even have a liquid water ocean hidden under the surface ice, providing the possibility for the gestation of life. The discovery of this cocrystal is not only applicable to Titan, but may also help scientists understand molecular evolution and prebiotic chemical processes in other cold environments in the universe.

Compiled from /ScitechDaily