Two distinct current systems in the ionosphere of Mars.

When the solar wind interacts with the ionosphere of an unmagnetized planet, it induces currents that form an induced magnetosphere. These currents and their associated magnetic fields play a pivotal role in controlling the movement of charged particles, which is essential for understanding the escape of planetary ions. Unlike the well-documented magnetospheric current systems, the ionospheric current systems driven by solar wind and atmospheric neutral winds have not been quantitatively observed, which constrains the quantification of energy transfer from stars to these planets.

Weak magnetism of Martian impact basins may reflect cooling in a reversing dynamo.

Understanding the longevity of Mars's dynamo is key to interpreting the planet's atmospheric loss history and the properties of its deep interior. Satellite data showing magnetic lows above many large impact basins formed 4.1-3.

Thickness and structure of the martian crust from InSight seismic data.

A planet's crust bears witness to the history of planetary formation and evolution, but for Mars, no absolute measurement of crustal thickness has been available. Here, we determine the structure of the crust beneath the InSight landing site on Mars using both marsquake recordings and the ambient wavefield. By analyzing seismic phases that are reflected and converted at subsurface interfaces, we find that the observations are consistent with models with at least two and possibly three interfaces.

Timing of the martian dynamo: New constraints for a core field 4.5 and 3.7 Ga ago.

The absence of crustal magnetic fields above the martian basins Hellas, Argyre, and Isidis is often interpreted as proof of an early, before 4.1 billion years (Ga) ago, or late, after 3.9 Ga ago, dynamo.