Active volcanoes on Mars? Noxious gas discovery says — maybe

Are there still active volcanoes on Mars? New detections of hydrogen chloride from below the surface suggest flowing magma. The post Active volcanoes on Mars? Noxious gas discovery says, maybe first appeared on EarthSky. The science-journalism coverage adds useful context, while the strongest evidential footing still comes from the underlying data, papers or institutional documentation.

It matters because Earth science becomes stronger when local observations can be placed inside a broader physical pattern that spans time and geography. The planet operates as a coupled system in which atmospheric, oceanic, cryospheric and solid-Earth processes interact across timescales from days to millions of years. A measurement that captures one variable at one location and one moment has limited interpretive value until it is embedded in the longer series and wider spatial coverage that allow natural variability to be separated from forced change. The European Space Agency’s Trace Gas Orbiter (TGO) detected the gas hydrogen chloride coming from some of the cracks. NASA’s InSight lander detected more than 1, 300 seismic events, revealing that Mars still experiences marsquakes.

Now, an international team of researchers says it has found perhaps the strongest evidence yet that Mars might still be volcanically active, with magma moving beneath its surface. The researchers said on November 4, 2026, that the European Space Agency’s Trace Gas Orbiter (TGO) has detected the gas hydrogen chloride (HCl) above cracks in the Martian.

The researchers published their new peer-reviewed findings in Science Advances on November 4, 2026. Detections of hydrogen chloride at low altitudes, unexplained by observed atmospheric state and models, together with the geological context of the region, hint at an igneous.

This gas isn’t seen as much during Mars’ colder seasons because its molecules are quickly “absorbed” by water ice crystals and disappear from the observations. The researchers said it’s likely that the hydrogen chloride seeped into Mars’ atmosphere from these cracks.

The broader interest lies in linking the observation to climatic, geophysical or environmental dynamics that extend well beyond the immediate event or location. Earth science is unusual in that its most important questions operate on timescales that no single research career can observe directly, making the archival record, whether in ice, sediment, rock or satellite data, as important as any new measurement. Results that can be embedded in that record, and that either confirm or challenge the patterns it reveals, carry disproportionate scientific weight.

Observations by Atmospheric Chemistry Suite led to the widespread observations of hydrogen chloride at part-­per-­billion levels in the atmosphere of Mars during the warm. Here, we report hydrogen chloride detections during the cold aphelion season that are isolated in the Alba Mons region.

Because this item comes through EarthSky as science journalism, it should be treated as contextual reporting rather than primary evidence. Good science reporting can identify why a result matters, connect it to the wider literature and make technical work readable, but the decisive evidence remains in the original paper, dataset, mission release or technical record. That distinction is especially important when a story is later repeated by aggregators, because repetition increases visibility, not evidential strength.

The next step is to place the result inside longer time series and to compare it with independent instruments and independent sites. Earth system observations gain most of their interpretive power from network density and temporal depth, not from any single measurement however precise. Model simulations that assimilate the new data will help clarify whether the observation fits comfortably within known natural variability or represents a shift that existing models do not reproduce.

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