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HomeSciencePossible rewrites: - The turbulence and vigor of the sun might have triggered...

Possible rewrites: – The turbulence and vigor of the sun might have triggered the beginning of life on Earth. – An unsettled and energetic sun could have jumpstarted the origin of life on our planet. – The tumultuous and animated behavior of the sun may have initiated the emergence of life on Earth.


Artist’s concept of the early Earth. Credit: NASA

A new study has found that the building blocks of life on Earth may have been formed by volcanic eruptions from our sun.

A series of chemical experiments show how particles from the sun, when they collide with gases in Earth’s early atmosphere, can form amino acids and carboxylic acids, the building blocks of proteins and organic life. The results have been published in the journal life.

To understand the origins of life, many scientists are trying to explain how amino acids, the raw materials that make up proteins and all forms of cellular life, are formed. The most famous suggestion arose in the late 19th century in which scientists speculated that life might have begun in a “warm little pond”: a soup of chemicals, activated by lightning, heat and other energy sources, that could mix together in concentrated amounts to form organic molecules.

In 1953, Stanley Miller of the University of Chicago attempted to recreate these primordial conditions in the laboratory. Miller filled a sealed chamber with methane, ammonia, water and molecular hydrogen—gases thought to be dominant in Earth’s early atmosphere—and repeatedly fired an electric spark to simulate lightning. A week later, Miller and his graduate advisor Harold Urey analyzed the contents of the room and found that 20 different amino acids had formed.

“This was a huge revelation,” said Vladimir Irapetyan, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and co-author of the new paper. “From the primary components of early Earth’s atmosphere, you can synthesize these complex organic molecules.”

But the past seventy years have complicated this interpretation. Scientists now believe that ammonia (NH3) and methane (CH4) were less abundant; Instead, Earth’s air was filled with carbon dioxide (CO2) and molecular nitrogen (N2), which require more energy for decomposition. These gases are still able to produce amino acids, but in significantly smaller amounts.

In search of alternative energy sources, some scientists have pointed to shock waves from incoming meteorites. Others pointed to solar ultraviolet radiation. Airapatian, using data from NASA’s Kepler mission, pointed to a new clue: energetic particles from our sun.

Energy from our young sun 4 billion years ago helped create molecules in Earth’s atmosphere that allowed it to heat up enough to harbor life. Credit: NASA’s Goddard Space Flight Center/Jenna Duberstein

Kepler has observed distant stars at various stages in their life cycles, but its data provide hints about our sun’s past. in 2016, Airapetian published a study Which indicates that during the first 100 million years of the Earth’s life, the Sun was 30% darker. But solar “superplanets” – powerful eruptions we only see once every 100 years or so – would have erupted once every 3-10 days. These superplanets release particles close to the speed of light that would regularly collide with our atmosphere, starting chemical reactions.

“As soon as I published that paper, a team from Yokohama National University contacted me from Japan,” Airapetian said.

Dr. Kobayashi, a professor of chemistry there, had spent the past 30 years studying the chemistry of prebiotics. He was trying to understand how galactic cosmic rays – particles from outside our solar system – could have affected the atmosphere of the early Earth. “Galactic cosmic rays are ignored by most researchers because they require specialized equipment, such as particle accelerators,” Kobayashi said. “I was fortunate enough to have access to several of them near our facilities.” Slight modifications to Kobayashi’s experimental setup could test Airabatian’s ideas.

Airapetian and Kobayashi and their collaborators created a mixture of gases that corresponds to the early Earth’s atmosphere as we understand it today. They collected carbon dioxide, molecular nitrogen, water, and a variable amount of methane. (The proportion of methane in the early Earth’s atmosphere is uncertain but thought to be low.) They shot the gas mixture with protons (simulating solar particles) or ignited it with a spark discharge (simulating lightning), repeating the Miller-Urey experiment for comparison.

Close-up of a solar volcanic eruption, including a solar flare, a coronal mass ejection, and a solar volcanic eruption event. Credit: NASA’s Goddard Space Flight Center

As long as the methane content was greater than 0.5%, the mixtures released by the protons (the solar energy particles) produced detectable amounts of amino acids and carboxylic acids. But spark (lightning) discharges require a methane concentration of about 15% before any amino acids can form at all.

“Even when there is 15% methane present, the rate of production of amino acids by lightning is a million times lower than the production of protons,” Ayrapetyan added. Protons also tend to produce more carboxylic acids (procurers of amino acids) than those ignited by spark discharge.

All else being equal, solar particles seem to be a more efficient source of energy than lightning. All else was not equal, Airapetian suggested. Miller and Urey hypothesized that lightning was as common in Warm Little Pond’s time as it is today. But lightning, which comes from thunderclouds formed from rising warm air, would have been about 30% rarer under dim sunlight.

“During cold conditions, you never have lightning, and early Earth had very dim sunlight,” Airapetian said. “That doesn’t mean it couldn’t come from lightning, but lightning seems less likely now, and particles from the sun seem more likely.”

These experiments suggest that our young, energetic Sun could have spurred the signs of life more easily, and perhaps earlier, than previously assumed.

more information:
Kensei Kobayashi et al, Composition of Amino and Carboxylic Acids in Weak Reduction of Planetary Atmospheres by Solar Particles from the Young Sun, life (2023). DOI: 10.3390/life13051103

Courtesy of NASA’s Goddard Space Flight Center

the quote: An Active and Stormy Sun May Have Started Life on Earth (2023, May 2), Retrieved May 2, 2023 from https://phys.org/news/2023-05-stormy-sun-kickstarted-life-earth.html

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