Nav: Home

Scientific research will help to understand the origin of life in the universe

October 18, 2018

Until now, in the scientific community there has been the prevailing view that thermal processes associated exclusively with the combustion and high-temperature processing of organic raw materials such as oil, coal, wood, garbage, food, tobacco underpin the formation of PAHs. However, the scientists from Samara University, together with their colleagues from the University of Hawaii, Florida International University, and Lawrence Berkeley National Laboratory proved that the chemical synthesis of PAHs can occur at very low temperatures, namely -183 C.

Their attention to this topic was attracted, among other things, by the results of the NASA and the European Space Agency mission "Cassini-Huygens" to Saturn's largest moon, Titan. During the space mission of an automatic interplanetary station the benzene molecule was discovered in the atmosphere of Titan. This, in turn, led scientists to believe that the emergence and growth of the orange-brownish haze layers that surround this moon is exactly the responsibility of PAHs. However, the fundamental chemical mechanisms leading to the chemical synthesis of PAHs in the atmosphere of Titan at very low temperatures were not disclosed.

Within the framework of the megagrant "Development of Physically Grounded Combustion Models" under the guidance of Professor of Florida International University Alexander Mebel, the scientists from Samara University searched for the mechanisms of PAH formation using modern high-precision quantum chemical calculation methods. Based on these data, their colleagues from the University of Hawaii and Lawrence Berkeley National Laboratory conducted laboratory experiments that confirmed that prototypes of PAH molecules (anthracene and phenanthrene) are synthesized in barrier-free reactions that take place at low temperatures typical of Titan atmosphere. Anthracene and phenanthrene, in turn, are the original "bricks" for larger PAH molecules, as well as precursors of more complex chemical compounds that were found in the orange-brownish organic haze layers surrounding the moon of Saturn.

"Experimental detection and theoretical description of these elementary chemical reactions change the well-established notion that PAHs can be formed and are able to grow only at very high temperatures, for example, in flames of organic fuels under terrestrial conditions, - concluded Alexander Mebel. - And this means that our discovery leads to the changing of existing scientific views on how PAHs can be formed and grow."

"Traditionally, models of PAH synthesis in hydrocarbon-rich atmospheres of the planets and their moons, such as Titan, assumed the presence of high temperatures, - emphasizes Professor at the University of Hawaii Ralf Kaiser. We provide evidence for a low-temperature reaction pathway".

Understanding the mechanism of PAH growth at low temperatures will allow scientists to understand how complex organic molecules that are related to the origin of life can be formed in the Universe. "Molecules similar to small PAHs, but containing nitrogen atoms, are key components of ribonucleic acids (RNA, DNA) and some amino acids, that is, components of proteins, - notes Alexander Mebel. - Therefore, the growth mechanism of PAHs can be associated with chemical evolution in the Universe, leading to the origin of life".

Moreover, the study of the atmosphere of Titan helps to understand the complex chemical processes occurring not only on the Earth, but also on other moons and planets. "Using new data, scientists can better understand the origin of life on the Earth at the time when nitrogen was more common in its atmosphere, as it is now on Titan", - said Musahid Ahmed, a scientist at Lawrence Berkeley National Laboratory.

As for the application of the presented work it should be mentioned that the understanding the mechanism of PAH growth in flames will allow the scientists of Samara University to offer engineers the mechanisms to reduce the release of these carcinogenic substances in the exhaust of various types of engines. And this is one of the main goals of the megagrant implemented by the University.
-end-
For reference:

Polycyclic aromatic hydrocarbons are organic compounds which chemical structure contains two or more condensed benzene rings. In nature, PAHs are formed in the process of cellulose pyrolysis and are found in coal, brown coal and anthracite formations, and also as a product of incomplete combustion during forest fires. Many PAHs are potent carcinogens. The main sources of the emission of technogenic PAHs into the environment are enterprises of the energy complex, automobile transport, chemical and petroleum refining industry.

Megagrant "Development of Physically Grounded Combustion Models" has been implemented within the Russian Federation governmental support for scientific research since 2016. International scientific laboratory "Physics and Chemistry of Combustion" under the guidance of Professor of Florida International University Alexander Mebel was established to implement the megagrant in the University. The project is aimed at solving the burning problem -- prevention of environmental pollution. The results of research conducted by the scientists of Samara University in close cooperation with both international and Russian research centres will contribute to the creation of more environmentally friendly and efficient combustion chambers for gas turbine engines.

Samara University

Related Titan Articles:

Life on Titan cannot rely on cell membranes, according to computational simulations
Researchers from Chalmers University of Technology, Sweden, have made a new contribution to the ongoing search into the possibility of life on Titan, Saturn's largest moon.
Galactic cosmic rays affect Titan's atmosphere
Planetary scientists using the Atacama Large Millimeter/submillimeter Array (ALMA) revealed the secrets of the atmosphere of Titan, the largest moon of Saturn.
Nitrogen explosions created craters on Saturn moon Titan
Lakes of liquid methane on the surface of Titan, Saturn's largest moon, were likely formed by explosive, pressurized nitrogen just under the moon's surface, according to new research.
'Bathtub rings' around Titan's lakes might be made of alien crystals
The frigid lakeshores of Saturn's moon Titan might be encrusted with strange, unearthly minerals, according to new research being presented at the 2019 Astrobiology Science Conference, June 24-28, co-hosted by AGU and NASA in Bellevue, Wa.
SwRI scientist sheds light on Titan's mysterious atmosphere
A new Southwest Research Institute study tackles one of the greatest mysteries about Titan, one of Saturn's moons: the origin of its thick, nitrogen-rich atmosphere.
Astronomers find a cosmic Titan in the early universe
An international team of astronomers has discovered a titanic structure in the early universe, just two billion years after the Big Bang.
Unexpected atmospheric vortex behavior on Saturn's moon Titan
A new study led by a University of Bristol earth scientist has shown that recently reported unexpected behavior on Titan, the largest moon of Saturn, is due to its unique atmospheric chemistry.
Cassini's legacy and the atmospheric chemistry of Titan (video)
The Cassini-Huygens mission to Saturn, a collaboration between NASA and the European Space Agency, is set to end on Sept.
ALMA confirms complex chemistry in Titan's atmosphere
Saturn's frigid moon Titan has a curious atmosphere. In addition to a hazy mixture of nitrogen and hydrocarbons, like methane and ethane, Titan's atmosphere also contains an array of more complex organic molecules, including vinyl cyanide, which astronomers recently uncovered in archival ALMA data.
Scientists describe origins of topographic relief on Titan
Fluid erosion has carved river networks in at least three bodies in our solar system in the form of water on Earth and Mars and liquid hydrocarbons on Titan.
More Titan News and Titan Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Biology Of Sex
Original broadcast date: May 8, 2020. Many of us were taught biological sex is a question of female or male, XX or XY ... but it's far more complicated. This hour, TED speakers explore what determines our sex. Guests on the show include artist Emily Quinn, journalist Molly Webster, neuroscientist Lisa Mosconi, and structural biologist Karissa Sanbonmatsu.
Now Playing: Science for the People

#569 Facing Fear
What do you fear? I mean really fear? Well, ok, maybe right now that's tough. We're living in a new age and definition of fear. But what do we do about it? Eva Holland has faced her fears, including trauma and phobia. She lived to tell the tale and write a book: "Nerve: Adventures in the Science of Fear".
Now Playing: Radiolab

The Wubi Effect
When we think of China today, we think of a technological superpower. From Huweai and 5G to TikTok and viral social media, China is stride for stride with the United States in the world of computing. However, China's technological renaissance almost didn't happen. And for one very basic reason: The Chinese language, with its 70,000 plus characters, couldn't fit on a keyboard.  Today, we tell the story of Professor Wang Yongmin, a hard headed computer programmer who solved this puzzle and laid the foundation for the China we know today. This episode was reported and produced by Simon Adler with reporting assistance from Yang Yang. Special thanks to Martin Howard. You can view his renowned collection of typewriters at: antiquetypewriters.com Support Radiolab today at Radiolab.org/donate.