Researchers have identified a surprising force compressing plasma in Mars' upper atmosphere, likening the process to squeezing toothpaste from a tube. Dubbed the Zwan-Wolf effect, this phenomenon was previously observed on Earth but was considered impossible on the Red Planet. The discovery challenges existing models of how solar wind interacts with Martian ionized gas.
The finding emerged from analysis of data collected by the MAVEN spacecraft, which has been orbiting Mars since 2014. Its detection suggests that fundamental similarities exist between planetary magnetospheres, even on worlds lacking a global magnetic field. The effect could influence how quickly the planet’s atmosphere erodes over time.
According to the researchers, the Zwan-Wolf effect arises when magnetic fields in the solar wind reconnect in the upper atmosphere, creating pockets of compressed plasma. These regions accelerate particles toward the surface. One scientist noted, “I would never have guessed it,” expressing surprise at the mechanism's presence on Mars.
If the compression occurs more frequently or intensely than expected, it may accelerate atmospheric stripping. This process has already transformed Mars from a once wet, warm world into a cold desert. The finding could force a revision of models used to reconstruct Mars' ancient climate.
However, the study is based on a limited dataset, and the effect's long-term prevalence remains unconfirmed. Further observations from MAVEN and upcoming missions will be needed to verify its significance.