The Mars Perseverance rover has revealed distinct signatures of paleo-river and deltaic structures formed up to 4.2 billion years ago near the Jezero crater, providing new insight into the ancient Martian landscape’s watery history. Evidence of water on Mars persists in surface carbonate deposits, observable by the Perseverance rover’s various instruments. Using data from the rover’s ground-penetrating radar instrument, Emily Cardarelli and colleagues have now examined a sedimentary deposit called the Margin unit that is rich in magnesium carbonates, which preserve a record of the planet’s once-wet climate. It lies near a fluvial inlet to the Jezero crater, which was already known to contain features indicative of paleolakes and river deltas, including the Western Delta. During 78 traverses, Perseverance collected data from more than 35 meters underground – 1.75 times deeper than measured before at the Jezero crater. Radar reflection signatures showed that the Margin unit contains distinct river and deltaic features. Cardarelli et al. theorize that these structures could represent an ancient meandering river system, an alluvial fan, or braided river system. Furthermore, the findings suggest the region may have been a deltaic environment as early as the Noachian epoch (approximately 4.2 to 3.7 billion years ago), which would have predated the Western Delta’s formation. “This work also may have implications for the preservation of potential biosignatures and habitability in the subsurface of Jezero crater,” the authors write.

The mysterious properties of meteorites will be transformed into music and performed live at the Cambridge Festival this Saturday (21 March). Presented by experts from Anglia Ruskin University and the University of Cambridge, the event will allow the audience to experience space science in a new way by turning the microscopic textures and mineral structures of meteorites into melodies.

Magnetic fields are observed throughout the universe, including in very young galaxies where they extend across thousands of light-years. The standard explanation for the origin of these fields is the dynamo mechanism, in which turbulent motions in an ionized gas amplify weak seed magnetic fields over time. However, conventional dynamo theory predicts that building large-scale magnetic fields in galaxies should take several billion years. Observations of galaxies in the early universe that already host strong magnetic fields therefore present a major puzzle.

In a study published in Physical Review Letters, researchers propose a mechanism that may help resolve this discrepancy. They show that the gravitational collapse of plasma clouds during galaxy formation can significantly accelerate the amplification of magnetic fields.

Most visible matter in the universe exists as plasma — an ionized gas that can be stirred by gravity, temperature gradients, and rotation, producing turbulence. Turbulent flows contain swirling structures known as eddies, and the rate at which magnetic fields grow depends on how quickly these eddies turn over. The study finds that during gravitational collapse the properties of turbulence evolve in a way that leads to super-exponential growth of magnetic fields, allowing large-scale fields to develop up to possibly a hundred times faster than predicted by standard dynamo theory.

These results suggest that magnetic fields in galaxies could have formed much earlier than previously thought, potentially influencing galaxy evolution across cosmic time.