It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Tuesday, July 29, 2025
SPACE/COSMOS
Cosmic dust opens window on ancient atmosphere
Research team led by Göttingen University finds clues to early Earth’s air in fossilized micrometeorites
Since the beginning of Earth's history, tiny particles of rock and metal from space have been hitting our planet. On clear nights, we can even see their traces as shooting stars. Trapped in layers of rock, these micrometeorites can remain preserved for billions of years. An international research team led by the University of Göttingen and including the Open University, the University of Pisa, and Leibniz University Hannover has developed a method that allows them to reconstruct the atmosphere of the past using fossilized micrometeorites. The results were published in Communications Earth & Environment.
Since the beginning of Earth's history, tiny particles of rock and metal from space have been hitting our planet. On clear nights, we can even see their traces as shooting stars. Trapped in layers of rock, these micrometeorites can remain preserved for billions of years. An international research team led by the University of Göttingen and including the Open University, the University of Pisa, and Leibniz University Hannover has developed a method that allows them to reconstruct the atmosphere of the past using fossilized micrometeorites. The results were published in Communications Earth & Environment.
When metallic micrometeorites from space enter the Earth's atmosphere, they melt. In addition, iron and nickel oxidise on contact with oxygen in the air. These processes create microscopic spherical structures. They consist of oxide minerals whose oxygen comes from the atmosphere. Countless numbers of them fall to Earth every year, where they are deposited. They offer great potential for drawing conclusions about the past, as their fossilised remains provide a preserved “chemical archive” of the atmosphere from the time of their formation.
The newly developed method allowed researchers at Göttingen University’s Geoscience Centre and the Leibniz University Hannover to determine the composition of oxygen and iron isotopes in tiny fossil micrometeorites from different geological periods with high precision for the first time. The ratios of different isotopes provide information about the isotopic composition of the early atmosphere. In addition, the data also allow conclusions to be drawn about CO2 concentrations at that time and about the formation of organic matter around the world, mainly due to plants photosynthesizing.
The study shows that these tiny spheres are a promising addition to the usual methods used in geological climate research for reconstructing past CO2 concentrations. “Our analyses show that intact micrometeorites can preserve reliable traces of isotopes over millions of years despite their microscopic size” explains lead author Dr Fabian Zahnow, formerly Doctoral Researcher at Göttingen University, now at the Ruhr University Bochum. At the same time, it became clear that geochemical processes in soil and rock change micrometeorites after they have landed on Earth, meaning careful geochemical investigation is essential.
Original publication: Zahnow F., et al. “Traces of the oxygen isotope composition of ancient air in fossilized cosmic dust.” Communications Earth & Environment
Cross-section of a micrometeorite found in the Antarctic. The various iron oxide minerals in shades of grey were formed by oxidation in the Earth's atmosphere. Scale bar: 10 micrometres = 0.01 millimetres
Chunks of rock from the chalk marl pit in Hannover. Researchers collected around 100 kilograms of sedimentary rock and searched for fossilized micrometeorites. They found an average of one micrometeorite per kilogram of rock.
A new study from NYU Abu Dhabi has found that high-energy particles from space, known as cosmic rays, could create the energy needed to support life underground on planets and moons in our solar system.
The research shows that cosmic rays may not only be harmless in certain environments but could actually help microscopic life survive. These findings challenge the traditional view that life can only exist near sunlight or volcanic heat. Published in the International Journal of Astrobiology, the study is led by the Principal Investigator of the Space Exploration Laboratory at NYUAD’s Center for Astrophysics and Space Science (CASS), Dimitra Atri.
The team focused on what happens when cosmic rays hit water or ice underground. The impact breaks water molecules apart and releases tiny particles called electrons. Some bacteria on Earth can use these electrons for energy, similar to how plants use sunlight. This process is called radiolysis, and it can power life even in dark, cold environments with no sunlight.
Using computer simulations, the researchers studied how much energy this process could produce on Mars and on the icy moons of Jupiter and Saturn. These moons, which are covered in thick layers of ice, are believed to have water hidden below their surfaces. The study found that Saturn’s icy moon Enceladus had the most potential to support life in this way, followed by Mars, and then Jupiter’s moon Europa.
“This discovery changes the way we think about where life might exist,” said Atri. “Instead of looking only for warm planets with sunlight, we can now consider places that are cold and dark, as long as they have some water beneath the surface and are exposed to cosmic rays. Life might be able to survive in more places than we ever imagined.”
The study introduces a new idea called the Radiolytic Habitable Zone. Unlike the traditional “Goldilocks Zone” — the area around a star where a planet could have liquid water on its surface — this new zone focuses on places where water exists underground and can be energized by cosmic radiation. Since cosmic rays are found throughout space, this could mean there are many more places in the universe where life could exist.
The findings provide new guidance for future space missions. Instead of only looking for signs of life on the surface, scientists might also explore underground environments on Mars and the icy moons, using tools that can detect chemical energy created by cosmic radiation.
This research opens up exciting new possibilities in the search for life beyond Earth and suggests that even the darkest, coldest places in the solar system could have the right conditions for life to survive.
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