Rock analysis indicates that life existed on Earth earlier than imagined

posted on 04/15/2022 06:00


(Credit: University College London/ Publicity)

Life existed on Earth earlier than predicted, says an international group of scientists. The team found evidence indicating the presence of microbes in hydrothermal vents on the planet’s surface 300 million years after its formation — that is, at least 3.75 billion years ago. Detailed in the latest issue of the specialized journal Science Advances, the discovery indicates that the conditions necessary for the emergence of living beings are relatively basic and also reinforces the hypothesis of the existence of life on other planets, the authors of the article indicate.

To reach the conclusion, the experts evaluated a rock the size of a fist, taken from a region called the Nuvvuagittuq Supracrustal Belt, located in Quebec, Canada. The material was collected in 2008 and is estimated to be between 3.75 billion and 4.28 billion years old. “The region is an ancient hydrothermal vent system, where cracks in the seafloor allow iron heated by Earth’s magma to pass through,” the authors detail.

In the analysis, they cut the rock into 100-micron pieces — one micron is equal to one thousandth of a millimeter — in order to be able to observe the tiny structures of the material. Thus, they identified small filaments, as well as other structural evidence that the material had been created by bacteria. Among the detected forms that indicate a sign of life are a kind of stem filled with branches almost a centimeter long, a series of distorted spheres and tubes. “All these structures are very unique, and this indicates a biological origin, not a chemical one, which reinforces the possibility of microbes present in the analyzed material”, they explain.

In an interview with The Guardian, Dominic Papineau, a researcher at University College London in the United Kingdom reports that there are some similarities between the “tree-like” stem discovered by the group of scientists he led and filaments made by Mariprofundus ferrooxydans, a modern bacterium. found in iron-rich deep marine environments, a particular condition of hydrothermal vents.

The researchers also found a lot of evidence of how the bacteria present in this rock obtained energy, such as the presence of mineralized chemical by-products. According to the team, these elements are used by microorganisms that live on iron, light, sulfur and carbon dioxide, carrying out a kind of photosynthesis with the material. Taken together, these new findings suggest that a variety of microbial life may have existed as little as 300 million years after Earth formed. “In geological terms, this is fast. About one revolution of the Sun around the galaxy”, emphasizes Papineau, in a statement.

Scientific dating of the analyzed rock indicates that it is at least 3.75 billion years old and possibly up to 4.28 billion years old — the age of other volcanic rocks in which it is embedded. “I think it makes sense that this material is as old as the volcanic rocks that surround it, which would be 4.28 billion years,” says the leader of the study, which relied on the work of Canadian and Chinese scientists.

Timeline

Prior to this discovery, the oldest fossils with signs of life on Earth were found in Western Australia and dated to 3.46 billion years — 290 million years older than material found in Canada. According to the British team, this change in dates is extremely relevant to the timeline of the development of life on Earth and in other regions of the universe.

“Turning this clock back is very important because it tells us that it takes very little time for life to emerge on a planetary surface. Very quickly after the Earth formed, there was microbial life, which probably fed on iron and sulfur in these hydrothermal vents. “, justifies Papineau. “If life is relatively quick to emerge, given the right conditions, that increases the chance that life exists on other planets.”

  • Material was taken from volcanic rocks in Canada: belt was once part of the sea floor

    Material was taken from volcanic rocks in Canada: belt was once part of the sea floor
    Photo: D. Papineau.

  • Microscopic image of the analyzed fossil: filaments similar to those created by modern bacteria

    Microscopic image of the analyzed fossil: filaments similar to those created by modern bacteria
    Photo: D. Papineau.

Planet of three suns disappears

In 2016, a group of American astronomers announced the discovery of a planet four times the size of Jupiter and with three suns. In a study published yesterday in the journal Science, the team backtracked. After evaluations of the disappearance of the celestial body — made by them and by other specialists — it is concluded that it does not exist.

The scientists reported in the paper that the light signal from the supposed planet was actually a much more distant star that was behind the three suns studied. “It was a real blow,” said Kevin Wagner, a researcher at the University of Arizona, in the United States, and one of the authors of the study, in an interview with the newspaper El País. “When we published our study, we were pretty sure. The spectrum, brightness and motion of the object made it look entirely like a planet in a triple solar system. And we calculated that the possibility of it being a false positive was very low,” he added.

At the time of the discovery, the European Southern Observatory, owner of the telescope used in 2016 by experts, announced in a statement that the new planet was more exotic than Tatooine, the imaginary planet from the Star Wars saga, which had two suns in the sky. At the time, other researchers carried out analyzes in the same region where the supposed planet is located, in the constellation of Centaurus, 320 light-years from Earth, and were convinced of its existence.

The authors of the study point out that as difficult or embarrassing as it may seem, the case of the missing planet shows how scientists need to admit possible mistakes and also carry out longer-lasting analyses, as the first study was published after just 11 months of observations.

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