A recent discovery on Mars has shed light on the possible origins of life on Earth. Researchers have found that organic material present in the sediment of ancient Martian lakebeds points to widespread carbon chemistry on the Red Planet.
This discovery provides valuable insights into how the ingredients for life arrived on our planet billions of years ago.
Discovery of organic material on Mars
Ten years ago, a robotic rover on Mars unearthed a crucial piece of evidence by discovering organic material in the sediment of ancient lakebeds. This discovery indicated that Mars has a rich presence of carbon chemistrywhich raises intriguing questions about the origin of these organic molecules. While the presence of organic material does not necessarily imply the existence of extraterrestrial life, it opens up fascinating possibilities about the processes that might produce such molecules.
Planetary scientist Yuichiro Ueno of the Tokyo Institute of Technology led the team that made this discovery. The researchers found that carbon dioxide in the Martian atmosphere reacts with ultraviolet sunlight, creating a spray of carbon molecules that descends onto the planet’s surface. “Such complex carbon-based molecules are the prerequisite for life, the building blocks of life, you might say,” explained chemist Matthew Johnson of the University of Copenhagen. He further clarified that these organic molecules form through atmospheric photochemical reactions without any biological intervention.
The role of photolysis
Photolysis, a process in which molecules are broken down by light, plays an important role in the formation of organic compounds on MarsThis process produces carbon monoxide and oxygen atoms from carbon dioxide, and works faster on lighter isotopes. As a result, molecules containing carbon-12 are depleted faster than molecules containing carbon-13, leaving a “surplus” of carbon-13 dioxide. The idea that photolysis contributes to the organic chemistry found on Mars is supported by simulations and subsequent studies.
Johnson and his colleagues published a paper in 2013 in which they hypothesized that photolysis could explain the presence of organic molecules on Mars. The recent findings provide hard evidence to support this hypothesis. The atmospheric carbon-13 enrichment was first identified a few years ago when researchers Mars meteorite that landed in Antarctica. “The evidence is that the ratio of carbon isotopes in it matches exactly what we predicted in the quantum chemical simulations,” Johnson said.
Confirmation of Martian meteorite
A crucial piece of evidence was found in data obtained by the Curiosity rover in Gale Crater. The samples from the rover of carbonate minerals showed a carbon-13 depletion which perfectly reflected the carbon-13 enrichment in the Martian meteorite.
This finding confirmed that the organic material on Mars was formed from carbon monoxide produced by Photolysis. “There is no other way to explain both the decrease in carbon-13 in the organic material and the enrichment in the Martian meteorite, both in relation to the composition of the volcanic CO2 being emitted on Mars,” Johnson explains.
The confirmation of the Curiosity rover provides strong evidence that photolysis is responsible for the formation of organic material on Mars. This discovery also points to a possible origin for organic material on earthBillions of years ago, Venus, Earth and Mars all had similar atmospheres, suggesting the same processes were likely occurring on our home planet as well.
Implications for the origin of the Earth
The implications of this discovery extend beyond Mars. The study suggests that the organic material found on Mars could provide clues to the origins of life on Earth. During the early stages of the solar system, Earth, Venus and Mars had similar atmospheric conditions. The processes that led to the formation of organic molecules on Mars could also have occurred on Earth and laid the foundation for the emergence of life.
“We haven’t found this smoking gun material here on Earth to prove that the process has happened. Maybe because the Earth’s surface is much more alive, geologically and literally, and therefore constantly changing,” Johnson said. “But it’s a big step that we’ve now found it on Mars, from a time when the two planets were very similar.”
