The Red Planet’s iconic rusty dust has a much wetter history than previously assumed, find scientists combining European Space Agency (ESA) and NASA spacecraft data with new laboratory experiments on replica Mars dust. The results suggest that Mars rusted early in the planet’s ancient past, when liquid water was more widespread.

However, new analysis of spacecraft observations in combination with novel laboratory techniques shows that Mars’s red colour is better matched by iron oxides containing water, known as ferrihydrite. Ferrihydrite typically forms quickly in the presence of cool water, and so must have formed when Mars still had water on its surface.

  • lemmyngEnglish
    27·
    17 hours ago

    The missing part in OP’s excerpt: It was previously assumed that the rust was hematite, which forms in dry conditions.