Volume 8 Issue 10, October 2024

In hyperarid environments, life can obtain water through salts that draw moisture from the atmosphere. These salts, then, should be a focus of searches for life on Mars. The experiments performed by NASA’s Viking landers may have accidentally killed Martian life by applying too much water.

Early in the history of the Solar System, the giant planets — including Jupiter and Saturn — migrated under gravity into different orbits around the Sun, causing an epoch of chaos and collisions. Radioactive isotopes in asteroids record the thermal imprint of these collisions, and a broad survey of meteorites now constrains the timing of the migration to approximately 11 million years after the Solar System formed.

A probabilistic machine learning method trained on cosmological simulations is used to determine whether stars in 10,000 nearby galaxies formed internally or were accreted from other galaxies during merging events. The model predicts that only 20% of the stellar mass in present day galaxies is the result of past mergers.

This Perspective presents the evidence in favour of and against the existence of an ancient ocean covering the Martian northern plains (Vastitas Borealis), discussing in particular the contribution of the Chinese Zhurong rover observations in supporting the presence of an ocean and the key role of the upcoming sample return.

Serpentinization — the metamorphism of rocks involving large amounts of water — includes many different aspects linked to habitability and offers a more reliable indicator of habitable conditions in the Solar System than a single diagnostic, such as water.

Centaur 29P/Schwassmann–Wachmann 1 exhibits a fascinating outgassing pattern in JWST observations, with compositional heterogeneities that may be related to the bilobate nature of its nucleus. The detection of CO and CO₂ isotopologues is also reported.

Chuanpeng Hou and co-authors report their findings on the origin of interplanetary switchbacks in solar magnetic reconnection at chromospheric network boundaries. This link between in situ and remote-sensing solar observations is a major step towards understanding coronal heating and solar wind acceleration.

The organic macromolecular matter found in meteorites could have formed in heavily irradiated zones in dust traps in planet-forming disks, according to an evolutionary model of a protoplanetary disk.

Radiometric cooling ages of chondrite meteorites record asteroid belt bombardment beginning approximately 11 million years after the formation of the Solar System, indicating an episode of giant planet migration at that time.

An analysis of the gravitational waves emitted from the neutron star binary merger GW170817 provides constraints on the out-of-equilibrium (viscous) properties of neutron star matter.

How a star cluster manages to produce γ-rays at a location 30 light yr away from itself is a mystery that can be solved by carefully testing theories about how charged particles travel through space.

Using a sample of more than 2,600 classical Cepheids with precise distances and ages, Huang et al. have discovered that the Milky Way’s disk warp undergoes retrograde precession, revealing the presence of a slightly oblate dark matter halo.

A reconstruction of the light profile for the Milky Way from an internal perspective provides an estimate of the Galaxy’s size that can be directly compared to other galaxies. This property will help to understand how typical the Milky Way is.

The contribution of accreted stars to a galaxy’s total stellar mass is hard to determine directly from observations. Here constraints are placed on the ex situ stellar mass for ~10,000 galaxies using a cosmological simulation and machine learning.

Merging supermassive black holes emit low-frequency gravitational waves, difficult to observe with current and future detectors. Stegmann et al. show that these black holes can leave measurable traces in high-frequency signals from adjacent sources.

Machine learning provides an opportunity to probe dark matter in massive galaxy clusters, more precisely and hundreds of times faster than current methods.

The Origin of Life Space Experiment, conducted on China’s Space Station Tiangong, aims to investigate the origin of genetic codes and its relation with gravity effects.