Volume 7 Issue 3, March 2023

Low Earth orbits are increasingly congested, impacting astronomical observations and dark skies. Globally coordinated regulatory policies and mitigation strategies are among urgent next steps to protect this shared environment and intangible heritage.

Unfettered access to dark night skies is rapidly diminishing, due to light pollution and satellite constellation tracks. Scientists should do more to stand up to ‘big light’ and ‘big space’ and preserve this natural resource.

A solar-cycle-length study reveals the detailed structure of the outer heliosphere. The boundary of our heliosphere is more dynamic and structured than previously known.

More than 500 participants from around the globe registered for the first Astronomers for Planet Earth Symposium, to discuss and push for more sustainability in the field of astronomy as well as opportunities for astronomers to contribute to climate communication.

Over the last ten billion years, star formation in the Universe has been on the decline. Astronomers met at the University of Cambridge to discuss causes and themes of galaxy quenching.

A device combining a pulsed laser system with an Orbitrap mass analyser is well-suited for in situ exploration of prime astrobiological targets, such as Enceladus. Here a prototype of this instrument that is optimized for spaceflight applications demonstrates that this device could be used to characterize chemical biosignatures in future missions.

Each space launch is assessed for various risks, but not its wider impacts. This Perspective shows how the aggregate effects of space launches, plus the attendant rise of space debris, affect the darkness of our night sky now and in the future.

Models for night sky brightness are used to characterize sites for astronomical observatories, but in the presence of artificial light pollution, certain assumptions regarding aerosol shapes mean that the estimates are systematically underestimated, particularly at low altitudes.

Harnessing the power of citizen science and machine learning, this study takes in 20 years of Hubble Space Telescope images, of which 2.7% show satellite streaks, and predicts that this fraction will increase by up to an order of magnitude in the next decade.

Lunar high-concentration ferric ion (Fe³⁺/∑Fe > 40%) and ~63% of nanophase metallic iron (npFe⁰) are produced via charge disproportionation of ferrous iron from micrometeoroid impacts, as observed in the Chang’e-5 sample. This ongoing process would lead to a continuously increasing abundance of Fe³⁺ in the lunar regolith.

Combined analysis of Chang’e-3 in situ measurements and Chang’e-5 laboratory samples, with an updated chronology from Chang’e-5 data, reconstructed the relation between age and composition of young lunar mare basalts. Results indicate persistent volcanism 2 Gyr ago, indicative of the presence of a heat source at the time.

Wind power can be an oft-neglected source of energy for future human exploration missions on Mars, especially coupled with solar power. Modelling shows that solar and wind energy can fully power such missions for more than half of the Martian year for ten regions of interest identified by NASA. Another 13 promising sites are identified.

The aqueous activity responsible for carbonate formation on Ryugu happened much earlier—less than 1.8 million years after CAI formation—than estimates (4–6 Myr) from carbonaceous chondrite meteorites. Ryugu’s parent body either was smaller than ∼20 km in diameter or was disrupted before reaching the high temperatures required.

Observations of a meteoroid coming from the Oort cloud show that it is made of rocky and not icy material, constraining the ratio of rocky to icy objects impacting Earth from the Oort cloud to \({6}_{-5}^{+13}\)%.

A planetary origin model that forms exoplanets from a narrow ring of silicate material at a stellocentric distance of 1 au is able to explain the physical properties of super-Earths and reproduce the ‘peas in a pod’ pattern of uniformity within planetary architecture.

An abrupt slow-down in a magnetar’s rotation rate (a ‘glitch’) may be related to the subsequent emission of three radio bursts (resembling fast radio bursts) and a month-long episode of pulsed radio emission.

Through mapping the gamma-ray flux in giant molecular clouds, it appears that low-energy cosmic rays hardly penetrate into dense, potentially star-forming, clumps. This finding implies a slower diffusion of cosmic rays in these clumps, possibly caused by higher levels of magnetic turbulence than anticipated.

A miniaturized instrument comprising a pulsed UV laser system and an Orbitrap analyser enables the characterization of the organic content and chemical composition of planetary materials, supporting the science objectives of future planetary missions.