Iron particles, from meteorites or volcanic ash, could have catalyzed the chemical reactions that formed the building blocks of life over four billion years ago on Earth, a new study suggests.
The oldest fossil evidence for life on Earth is estimated to be between 3.75 and 4.28 billion years old, but nobody really knows how or when life got a foothold on our planet. One way of working toward an answer is to identify how the vital chemical building blocks for life — organic compounds that assemble into amino acids, proteins and eventually RNA and DNA strands — first formed.
Oliver Trapp, a professor of organic chemistry at the Ludwig Maximilians University in Munich and the Max Planck Institute for Astronomy, realized that a process used in chemical engineering that turns carbon monoxide and hydrogen into hydrocarbons (molecules made from carbon and hydrogen atoms), using metallic particles as catalysts, could also have created the hydrocarbon building blocks of life on Earth.
Related: Meteorites could have brought all 5 genetic 'letters' of DNA to early Earth
In particular, Trapp was thinking of iron contained within meteorites as being a potential catalyst.
Trapp's colleague at the Ludwig Maximilians University, Dmitry Semenov, then suggested that iron particles in volcanic ash could also have performed that role. Together with Ludwig Maximilians' Sophia Peters and Rupert Hochleitner of the Mineralogical State Collection Munich, they performed a series of experiments testing both propositions.
The early Earth's atmosphere is thought to have been a noxious mix of methane, hydrogen sulfide and up to 200 times as much carbon dioxide as our air currently contains. Using particles from iron meteorites, iron from stony meteorites, and ash from Mount Etna in Sicily, the experiments showed how iron could have acted as a catalyst for converting carbon dioxide and hydrogen in the early Earth's atmosphere into hydrocarbons, including acetaldehyde and formaldehyde. These organic compounds are among the building blocks of fatty acids, DNA nucleobases, sugars and amino acids.
Furthermore, the team tested the reactions in all manner of environmental conditions, since the exact environment of the early Earth is unknown.
For example, how volcanic was the early Earth? "Unfortunately, there are almost no geological records from earlier than four billion years ago, so we don't really know how many active volcanoes would have been present at that time," Semenov told Space.com in an interview.
A significant degree of volcanism would have been needed to produce enough catalysts, but too much and the ash would have blocked the young sun's light, reducing temperatures on Earth. All the experiments required temperatures above 300 degrees Fahrenheit (150 degrees Celsius) to operate efficiently, and the young Earth, perhaps tens of millions to 100 million years after the formation of the moon 4.5 billion years ago, would still have been very hot, with steaming oceans above recently solidified magma.
Earth was also being heavily bombarded by meteorites and asteroids during this era, evidence for which can be found in the form of them having left their mark on our nearest neighbor, the moon.
While it remains unclear whether the dominant source of catalysts would have been meteorites or volcanoes, their new model joins others that also describe how life's building blocks could have formed. These include chemical reactions in hydrothermal vents deep in the ocean floor, the formation of organic molecules in deep space that were then brought to Earth by meteorites and asteroids, and lightning discharges in a hydrocarbon-rich atmosphere.
However, it may not necessarily be a competition between rival models; all of them could have been important to some degree.
"I personally believe that a multitude of organic syntheses and sources of organic matter have contributed to the origin of life," said Semenov. "The relative importance of individual scenarios depends on the environment where the first life emerged, and we don't yet know exactly where it happened."
The findings, published online today (May 25) in the journal Scientific Reports, widen the range of possibilities for how life may have formed on Earth, and possibly increase the chances of it having formed elsewhere in the universe, too.
"The most important conclusion from our study is that the catalytic particles could have been produced both from meteoritic and volcanic sources," said Semenov. Whether meteorites or volcanoes were the dominant source of those catalysts, "the organic synthesis that we have studied experimentally would use whatever particles were available on the early Earth."
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Well, the other day we had this interesting report on how abiogenesis could get kick started. Solar 'superflares' millions of times stronger than anything today may have sparked life on Earth, https://forums.space.com/threads/solar-superflares-millions-of-times-stronger-than-anything-today-may-have-sparked-life-on-earth.61536/
Keep a list updated of these reports.
“The oldest fossil evidence for life on Earth is estimated to be between 3.75 and 4.28 billion years old, but nobody really knows how or when life got a foothold on our planet.” "Unfortunately, there are almost no geological records from earlier than four billion years ago, so we don't really know how many active volcanoes would have been present at that time," Semenov told Space.com in an interview. A significant degree of volcanism would have been needed to produce enough catalysts, but too much and the ash would have blocked the young sun's light, reducing temperatures on Earth. All the experiments required temperatures above 300 degrees Fahrenheit (150 degrees Celsius) to operate efficiently, and the young Earth, perhaps tens of millions to 100 million years after the formation of the moon 4.5 billion years ago, would still have been very hot, with steaming oceans above recently solidified magma. Earth was also being heavily bombarded by meteorites and asteroids during this era, evidence for which can be found in the form of them having left their mark on our nearest neighbor, the moon.”
My thought, this report by space.com does present some catastrophism in this explanation for the origin of life on Earth. The giant impact model for the origin of the Moon, many asteroid and meteorite bombardments and the Faint Young Sun are part of the story of abiogenesis creating life on Earth. Something that was not in Charles Darwin warm little pond from the early 1880s.
We had water at least as far back as 3.8 billion years ago, possibly 4.28 billion. (O'Neil-2012).
Other source says there was water starting only 2000 years after the impact of Theia, 4.5 billion years ago. (Sleep-2001)
Life could have taken as much as 750 million years to develop. This assumes water was in existence 4.5Bya but it took until 3.75Bya for life to occur.
BTW, "warm little pond" has insufficient energy to do the job. "Irradiated warm little pond" now on the scene.
Canadian bacteria-like fossils called oldest evidence of life, https://www.reuters.com/article/us-science-life-idUSKBN16858B, 01-March-2017. "WASHINGTON (Reuters) - Microfossils up to almost 4.3 billion years old found in Canada of microbes are similar to the bacteria that thrive today around sea floor hydrothermal vents and may represent the oldest-known evidence of life on Earth, scientists said on Wednesday."..."The scientists said the primordial microbes’ structure closely resembled modern bacteria that dwell near iron-rich hydrothermal vents. They believe that, like their modern counterparts, they were iron-eaters. The rock’s composition was consistent with a deep-sea vent environment."
My observation, fossil record evidence of life like this dated back 4.28 Gyr, does not show evolution of these microbes if they appear like what we see living today on Earth, just an observation. 4.28 Gyr ago, much bombardment and the giant impact model uses a proto-Earth with much less mass before the impact with postulated Theia. Reports I have in my home database, tracking all this good science (as I can) shows the atmosphere of the proto-earth could be chiefly stripped away and much water too in various reporting over the years. Microbes flourishing on Earth 4.28 Gyr ago is a problem for the warm little pond, even if *irradiated*. All kinds of catastrophic bombardments now in this period :)
Diverse life forms may have evolved earlier than previously thought, https://phys.org/news/2022-04-diverse-life-evolved-earlier-previously.html, April 2022.
"Diverse microbial life existed on Earth at least 3.75 billion years ago, suggests a new study led by UCL researchers that challenges the conventional view of when life began. For the study, published in Science Advances, the research team analyzed a fist-sized rock from Quebec, Canada, estimated to be between 3.75 and 4.28 billion years old. In an earlier Nature paper, the team found tiny filaments, knobs and tubes in the rock which appeared to have been made by bacteria...Lead author Dr. Dominic Papineau (UCL Earth Sciences, UCL London Center for Nanotechnology, Center for Planetary Sciences and China University of Geosciences) said: "Using many different lines of evidence, our study strongly suggests a number of different types of bacteria existed on Earth between 3.75 and 4.28 billion years ago." "This means life could have begun as little as 300 million years after Earth formed. In geological terms, this is quick—about one spin of the Sun around the galaxy."
Pinning down accurate dates for microbe fossils and if before 4 Gyr, working all that catastrophism operating in the early solar system into the abiogenesis experiments, could be very interesting.
Or it was just a left over bit of food from an aliens picnic basket.
Which came first, the universe or life? Or is that question a wrong question to ask in the first place? A different explanation being, from eternity to eternity, "the life of the universe (singular) . . . and of the universes (plural)." Not necessarily exactly life as we think we understand life, but still "building blocks" (a primordial soup) of foundational life always around and always underlying the life of the universe, or life in the universe, or both, as we think we know life to be.
Hmmm, to be continued elsewhere....
It is possible considering life is recorded about 4.2 billion years ago on earth. Some say not enough time to start on Earth.
We know that amino acids, the basic building blocks of DNA have been found in space.
The question is this.
If life evolved on Earth, where would it start?
Needs chemicals, amino acids.
Needs a neutral space where life can start and evolve.
Bottom of oceans near volcanic exhaust.
Away from the exhaust but close enough to absorb chemicals.
Presence of amino acids.
Time to evolve and diversify.
They are saying that experiments similar to above do not show high enough rates of synthesis. Higher energies are needed, such as cosmic rays or uranium disintegrations.
We may not even recognize a lot of the life as being life, at first glance, and there is a good possibility a lot of that life won't recognize Earth-life as being any kind of life.