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The Hayabusa2 spacecraft collected samples from the surface of the carbonaceous near-Earth asteroid (162173) Ryugu and brought them to Earth. The samples were expected to contain organic molecules, which record processes that occurred in the early Solar System. We analyzed organic molecules extracted from the Ryugu surface samples. We identified a variety of molecules containing the atoms CHNOS, formed by methylation, hydration, hydroxylation, and sulfurization reactions. Amino acids, aliphatic amines, carboxylic acids, polycyclic aromatic hydrocarbons, and nitrogen-heterocyclic compounds were detected, which had properties consistent with an abiotic origin. These compounds likely arose from an aqueous reaction on Ryugu’s parent body and are similar to the organics in Ivuna-type meteorites. These molecules can survive on the surfaces of asteroids and be transported throughout the Solar System.

Microbial coal-bed methane is an important economic resource and source of a potent greenhouse gas, but controls on its formation are poorly understood. To test whether the microbial degradability of coal limits microbial methane, we monitored methoxyl group demethylation—a reaction that feeds methanogenesis—in a global sample suite ranging in maturity from wood to bituminous coal. Carbon isotopic compositions of residual methoxyl groups were inconsistent with a thermal reaction, instead implying a substrate-limited biologic process. This suggests that deep biosphere communities participated in transforming plant matter to coal on geologic time scales and that methoxyl abundance influences coal-bed methane yield. Carbon isotopic enrichments resulting from microbial methylotrophy also explain an enigmatic offset in the carbon-13 content of microbial methane from coals and conventional hydrocarbon deposits.

The nature of the physiology and thermal regulation of the nonavian dinosaurs is the subject of debate. Previously, arguments have been made for both endothermic and ectothermic metabolisms on the basis of differing methodologies. We used clumped isotope thermometry to determine body temperatures from the fossilized teeth of large Jurassic sauropods. Our data indicate body temperatures of 36° to 38°C, which are similar to those of most modern mammals. This temperature range is 4° to 7°C lower than predicted by a model that showed scaling of dinosaur body temperature with mass, which could indicate that sauropods had mechanisms to prevent excessively high body temperatures being reached because of their gigantic size.

The widespread use of hydrogen fuel cells could have hitherto unknown environmental impacts due to unintended emissions of molecular hydrogen, including an increase in the abundance of water vapor in the stratosphere (plausibly by as much as ∼1 part per million by volume). This would cause stratospheric cooling, enhancement of the heterogeneous chemistry that destroys ozone, an increase in noctilucent clouds, and changes in tropospheric chemistry and atmosphere-biosphere interactions.

Recent evidence strengthens the case for signs of ancient life in rocks from Akilia, Greenland, but important questions remain.

Granites make up a large part of the continental crust. New data reveal their complex and diverse formation history, calling for a revision of the geological histories of many granites.

Clumped-isotope thermometry measurements of carbonate samples deposited in the Bolivian Altiplano as early as 28.5 million years ago and buried up to ∼5000 meters deep exhibit no relationship between burial depth and apparent temperature, and largely yield temperatures within error of plausible Earth-surface conditions. These results counter the predictions of Sempere et al . and support our previous conclusions regarding the uplift of the Altiplano.