Organic Molecules on Mars Provide Crucial Clues to Life’s Origins | New Discovery

“Discover how new findings of organic molecules on Mars provide crucial clues to life’s origins, supporting a decade-old theory about life’s building blocks. Learn how NASA’s Curiosity rover and researchers are uncovering secrets that link the Red Planet to the origins of life on Earth.”

In a groundbreaking study, two samples from Mars have provided the “smoking gun” evidence for the origin of Martian organic material. This discovery, led by researchers from the University of Copenhagen and the Tokyo Institute of Technology, supports a decade-old prediction about the formation of organic molecules. These molecules, essential for life, offer key insights into how life might have originated on Earth.

Curiosity Rover’s Important Role

For nearly 12 years, NASA’s Curiosity rover has been diligently exploring Mars, collecting soil samples and conveying the planet’s secrets. Recently, it discovered sedimentary organic material with unusual carbon isotope ratios, which initially puzzled scientists. Typically, such isotopic properties on Earth indicate the presence of microorganisms but can also result from non-biological chemical processes.

A Decade-Old Theory Confirmed

The new study, published in Nature Geoscience, has provided the missing link to a theory proposed over a decade ago. Co-author and chemistry professor Matthew Johnson explained that the discovery on Mars confirmed the hypothesis that the Sun broke down CO2 in Mars’ atmosphere billions of years ago. The resulting carbon monoxide reacted with other chemicals to synthesize complex organic molecules.

“Such carbon-based complex molecules are necessary conditions of life, the building blocks of life one might say,” said Johnson. “We show that the organic material found on Mars has been formed through atmospheric photochemical reactions—without life. This is the ‘egg,’ a prerequisite of life. It still remains to be shown whether or not this organic material resulted in life on the Red Planet.”

Linking Data from Mars and Earth

Twelve years ago, Johnson and his colleagues used quantum mechanics-based simulations to predict what happens when a CO2-rich atmosphere is exposed to UV light, a process known as photolysis. This process splits CO2 into oxygen and carbon monoxide, with carbon monoxide being depleted in carbon-13 and CO2 enriched in carbon-13.

Years ago, researchers identified this distinctive carbon-13 enrichment in a Martian meteorite found on Earth, known as Allan Hills 84001. The recent Curiosity sample, showing carbon-13 depletion, completes the puzzle, confirming the photolysis theory.

Implications for Earth and Beyond

The discovery is not only crucial for understanding Mars but also has significant implications for Earth. Early in their histories, Earth, Mars, and Venus had similar CO2-rich atmospheres. Photolysis likely played a role in the formation of organic molecules on Earth, potentially setting the stage for the emergence of life.

However, finding similar isotopic evidence on Earth is challenging due to geological changes over billions of years. “It is reasonable to assume that the photolysis of CO2 was also a prerequisite for the emergence of life here on Earth, in all its complexity,” Johnson explained.

The Science of Photolysis

Photolysis involves UV rays from the Sun providing energy for chemical transformations, such as breaking down CO2 into carbon monoxide and oxygen. This process favors the lighter carbon-12 isotope, resulting in distinct isotopic signatures in the resulting compounds.

Conclusion
The discovery of organic material with specific carbon isotope ratios on Mars has provided crucial evidence for understanding the origins of life’s building blocks. While it remains to be seen if life ever arose on Mars, this finding is a significant step forward in unraveling the mysteries of both Martian and terrestrial life.

Facts:

• Organic Material: The term refers to molecules containing carbon and at least one other element, essential for life but not necessarily indicating living organisms.
• Photolysis: A process where UV light breaks down molecules like CO2, critical for forming organic compounds.
• Isotopes: Variants of elements with different neutron numbers; carbon has two stable isotopes, carbon-12 and carbon-13, used to trace chemical reactions.

Extra Info:

• Mars Meteorite: Allan Hills 84001, found in Antarctica, contains carbonate minerals matching the isotopic predictions from photolysis.
• Atmospheric Evolution: Billions of years ago, Earth, Mars, and Venus had similar CO2-rich atmospheres before evolving differently due to various processes.

Reference:-

https://www.sciencedaily.com/releases/2024/07/240701232841.htm