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The first mass extinction

Featuring image: Life on during the Ordovician period looked very different then today. Animals like anomalocarididaes were very common, but many species vanished at the end of the Ordovician. A new study sheds light on the first mass extinction event. Model created by Espen Horn, photo: H. Zell, Creative Commons (CC BY-SA 3.0).

Paper: Geochemical Records Reveal Protracted and Differential Marine Redox Change Associated With Late Ordovician Climate and Mass Extinctions

Authors: N. P. Kozik, B. C. Gill, J. D. Owens, T. W. Lyons and S. A. Young

As mountains rise and continents fall apart, it not only changes the face of the Earth, but also drastically affects its inhabitants.

Earth’s biosphere was disrupted by several mass extinction events, often connected to great changes in large geologic cycles. These times of great disasters were also a chance for pioneers and led to great evolutionary leaps. A new study suggests that the oldest of the known major mass extinctions during the Ordovician was caused by a change in climate and the ocean’s circulation system.

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Do we need new types of geology to understand exoplanets?

Featuring image: White dwarf make perfect natural mass spectrometer, more powerful as any instrument on Earth. Can they help us to learn about exoplanets? NOIRLab/NSF/AURA/J. da Silva, Creative Common (CC BY 4.0)

Paper: Polluted white dwarfs reveal exotic mantle rock types on exoplanets in our solar neighborhood

Authors: K. D. Putirka and S. Xu

For a long time, geologist were only able to study rocks on the ground. We extended this knowledge to our neighbouring planets. Now finally, scientist have found a way to study rocks from planets far away, using the light of their host stars. And they look very strange.

Over the last 30 years, exoplanets have evolved from mere theory into a fantastic reality. Today we know that nearly all stars host at least one exoplanet and even exoplanets with an Earth-like mass are relatively common. Still, we know very little about the geology of these worlds. In a new study, Keith Putirka and Siyi Xu were able to observe and compare the mineralogy of exoplanets to that of the rocky planets in the solar system. Surprisingly, these exoplanets exhibit types of mineralogy unlike any we have known before.

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How did giant impacts influence our atmosphere?

Featuring image: Oxygen was not always present in Earth’s atmosphere, but stated to accumulate only around 3.5 billion years ago. Pixabay, Public Domain (CC0)

Paper: Delayed and variable late Archaean atmospheric oxidation due to high collision rates on Earth

Authors: S. Marchi, N. Drabon, T. Schulz, L. Schaefer, D. Nesvorny, W. F. Bottke, C. Koeberl and T. Lyons

Take a deep breath. Your lungs fill with air and vital oxygen. Not only you, but all higher life depends on oxygen. In the Archean aeon, which lasted from 4 to 2.5 billion years before present, Earth’s atmosphere contained no oxygen. How did oxygen accumulate in the atmosphere? A team of researchers discovered that the evolution of our atmosphere was strongly influenced by impacts of large meteorites when our planet was still young.

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Call of Cthulhu — Can we uncover the secret of Pluto’s red spots?

Featuring image: Pluto is an icy object in the outer solar system. Its surface it not only covered by ice, but also by an unidentified red material. The largest of these red areas is the Cthulhu region in the southern hemisphere. NASA/JHUAPL/SwRI, public domain (CC0)

Paper: Testing tholins as analogues of the dark reddish material covering Pluto’s Cthulhu region

Authors: M. Fayolle, E. Quirico, B. Schmitt, L. Jovanovic, T. Gautier, N. Carrasco, W. Grundy, V. Vuitton, O. Poch, S. Protopapa, L. Young, D. Cruikshank, C. Dalle Ore, T. Bertrand, A. Stern

Pluto is an icy object beyond Neptune. Its surface is not only covered by innocent pale ice, but also by mysterious dark-red fields. What lurks in these hellish regions and where do they come from?

Far behind Neptune’s orbit, the icy body Pluto orbits our Sun. Pluto got a lot of attention in 2006, when it lost its status as a planet. Since then, it remained as a trans neptunian objects (TNO) of major interest. In 2015, Pluto presented itself in high resolution pictures for the first time in history, when NASA’s space probe New Horizons explored the outer regions of our solar system. What the pictures showed, was not the expected icy desert, but multiple areas of deep red all over Pluto’s surface. The largest of them is located on the southern hemisphere. As a homage to the master of subtle horror, H. P. Lovecraft, the area is called Cthulhu region, because some of the most mysterious and powerful beings in Lovecraft’s world originate from Pluto (in Lovecraft’s stories called Yuggoth). Fayolle and co-workers tried to better understand the origin of these red materials by using laboratory experiments and numerical modelling in comparison with the data recorded by the New Horizons space probe.

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Mineralogy on other worlds

Featuring image: Titan seen in infrared light. NASA/JPL-Caltech/Stéphane Le Mouélic, University of Nantes, Virginia Pasek, University of Arizona, public domain (CC0)

Paper: Titan in a Test Tube: Organic Co-crystals and Implications for Titan Mineralogy

Authors: M. L. Cable, T. Runčevski, H. E. Maynard-Casely, T. H. Vu and R. Hodyss

Titan, Saturn largest moon, is a strange world. Its surface is covered by ice, dunes and haze of organic molecules and lakes of liquid methane. It even rains. The diversity of surface features may remind us of our own home planet, but the chemistry between these two celestial bodies lies worlds apart.

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Mysterious methane on Mars

Featuring image: northern rim of Gale Crater viewed by Curiosity. NASA/JPL-Caltech/MSSS, public domain (CC0)

Paper: Day-night differences in Mars methane suggest nighttime containment at Gale crater

Authors: C. R. Webster, P. R. Mahaffy, J. Pla-Garcia, S. C. R. Rafkin, J. E. Moores, S. K. Atreya, G. J. Flesch, C. A. Malespin, S. M. Teinturier, H. Kalucha, C. L. Smith, D. Viúdez-Moreiras and A. R. Vasavada

Methane is a gas often connected to life on Earth. NASA’s Mars rover reported the detection of methane, but discrepancies with other missions puzzled researchers. Is there methane on Mars or not? A new study tries to answer this question in a windy way.

Methane is a possible biosignature for extraterrestrial life and therefore, one of the goals of the Mars rover Curiosity was to search for methane. Curiosity was able to detect varying amounts of this gas over the years, but the existence of methane in the Martian atmosphere could not be confirmed by analysis from satellites. Now, Christopher Webster and his group were able to explain the variations as well as the discrepancy between ground-based and satellite analysis by developing a detailed model of the wind systems at Gale crater.

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Breaking the ice — Climate systems during Snowball Earth

Featuring image: modern sea ice at Antarctica. Denis Luyten (Wikimedia Commons), public domain (CC0).

Paper: Orbital forcing of ice sheets during snowball Earth

Authors: R. N. Mitchell, T. M. Gernon, G. M. Cox, A. R. Nordsvan, U. Kirscher, C. Xuan, Y. Liu, X. Liu, X. He

When you think about the Earth, you might imagine a blue and green globe orbiting the Sun. But the face of Earth has changed significantly over its life time and in the past, there were times when the Earth resembled more to a frozen, white snowball. Geologists, studying the climate during these cold epochs, found a connection between climate conditions in frozen oceans and variations of Earth’s orbit.

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Strange water — the source of water in our solar system

Featured Image: The star-forming nebula W51 is one of the largest “star factories” in the Milky Way galaxy, NASA/JPL, Public Domain (CC0)

Paper: Origin of hydrogen isotopic variations in chondritic water and organics

Authors: L. Piani, Y. Marrocchi L.G.Vacher H. Yurimoto M. Bizzarro

Vast blue oceans, swirly rain or fluffy white snow – water is ubiquitous on Earth. But where does the water of our solar system come from?

A group of researchers were able to investigate the isotopic composition of water in different components of meteorites. Their findings hint that some of the water on Earth may have originated from a source beyond the solar system.

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How lightning changes rocks – Reduction of phosphorus minerals

Featured Image: Lightning is a common high energy phenomenon on Earth, like here during a storm over Bucharest, Romania. Image credit: Catalin.Fatu (Wikimedia Commons), CC BY-SA 3.0.

Papaer: Lightning strikes as a major facilitator of prebiotic phosphorus reduction on early Earth

Authors: Benjamin L. Hess, Sandra Piazolo, Jason Harvey

You might think of lightning as a violent and destructive force of nature, but it might have helped to spark life on Earth. The enormous energy released by lightning can weather or even melt rocks. During this short but intense heating phase, the rock’s or soil’s mineralogy changes and a very important element for life becomes available: phosphorus. A group of researches was able to show why the transformation of phosphorus minerals by lightning could have been an important source of this element during Earth’s infancy.

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Are we star dust?

Paper: Amino acid abundances and compositions in iron and stony‐iron meteorites

Authors: Jamie E. Elsila, Natasha M. Johnson, Daniel P. Glavin, José C. Aponte, Jason P. Dworkin

All known life on Earth relies on amino acids. Many important biomolecules like proteins are made up of them. Scientists were surprised when they found these molecules, which are so strongly connected to living systems, in meteorites. How amino acids form in non-biological systems is still not entirely understood and is closely tied to the question of how life emerged on our young planet.

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