A recent study by Martin Rahm’s research group at Chalmers University has unveiled unexpected chemistry occurring on Saturn’s largest moon, Titan. This captivating find upends a century-old established chemical dictum that goes by the term “like dissolves like.” These considerations prompt crucial questions about the fate and transport of hydrogen cyanide in catastrophic situations.
Titan’s dynamic maze of icy mountains and a thick orange atmosphere make it an intriguing world. Its intricate carbon-based chemistry has mesmerized scientists for decades. Its strange conditions encourage the formation of lakes, seas, and sand dunes, providing a natural laboratory for examining the formation of prebiotic chemistry. Rahm, who is an Associate Professor in the Department of Chemistry and Chemical Engineering at Chalmers, led pioneering studies of the properties of hydrogen cyanide and its role in shaping Titan’s haze-rich atmosphere.
The Role of Hydrogen Cyanide
Hydrogen cyanide is found throughout the universe as well as on Earth. In space you encounter it everywhere, out in the big dust clouds, in the planetary atmospheres. On Titan, it is produced in the moon’s upper atmosphere. The question remains: what happens to hydrogen cyanide after its formation? Using large-scale computer simulations, Rahm and his team tried to answer this question. From their work, they tested thousands of arrangements to pack molecules in solid-state environments similar to those found on Titan.
The findings showed that hydrogen cyanide can react with hydrocarbons even at the very low temperatures present on Titan’s surface. This interaction directly goes against the rules of conventional chemistry, indicating that polar and nonpolar substances can interact in ways that were once deemed impossible.
“The discovery of the unexpected interaction between these substances could affect how we understand Titan’s geology and its strange landscapes of lakes, seas and sand dunes,” – Martin Rahm
Implications for Prebiotic Chemistry
Chalmers’ findings not only radically reshape our understanding of Titan’s geology, they have far-reaching implications for prebiotic chemistry. Hydrogen cyanide is arguably the single most important compound in the abiotic production of life’s building blocks. It is a critical ingredient in making all amino acids and nucleobases. These compounds are critical for DNA and RNA synthesis, as well as for building proteins and creating amino acid codes.
To Rahm, that kind of fundamental research is what will ultimately add to our understanding of how life can take hold in extreme environments. Notably, hydrogen cyanide can create polymeric networks with hydrocarbons. This unexpected discovery gives scientists a new avenue to explore in understanding chemical processes that may give rise to life outside our planet.
“In addition, hydrogen cyanide is likely to play an important role in the abiotic creation of several of life’s building blocks. Our work also contributes insights into chemistry before the emergence of life, and how it might proceed in extreme, inhospitable environments,” – Martin Rahm
Future Exploration and Collaborations
NASA’s upcoming Dragonfly mission holds the promise of further illuminating Titan’s mysteries. Dragonfly is currently scheduled for launch in 2028. It will reach Titan in 2034, where it will explore this rich world’s prebiotic chemistry and search for signs of life. The ongoing collaboration between Chalmers researchers and NASA represents an exciting opportunity to advance our understanding of hydrogen cyanide’s chemistry.
Rahm expresses enthusiasm about the ongoing exploration. He believes that continued investigations into hydrogen cyanide could yield significant discoveries regarding Titan’s evolution and its relevance to understanding our own planet’s early chemical history.
“This led to an exciting theoretical and experimental collaboration between Chalmers and NASA. The question we asked ourselves was a bit crazy: Can the measurements be explained by a crystal structure in which methane or ethane is mixed with hydrogen cyanide? This contradicts a rule in chemistry,” – Martin Rahm
He further adds, “I see it as a nice example of when boundaries are moved in chemistry and a universally accepted rule does not always apply.”