Mars’s iconic red color has long been attributed to iron oxide (rust) forming through interactions with water and oxygen. However, exciting new research published in February 2025 suggests that Mars’s red dust contains more water history than previously thought.
Key Findings of the Study
- Mars’s Red Color is Linked to Ferrihydrite, Not Just Hematite
- Previously, the red hue was thought to come primarily from dry iron oxides like hematite.
- The new study shows that Mars’s red dust is better matched by ferrihydrite, a hydrated iron oxide containing water.
- How the Discovery Was Made
- Scientists created mixtures of ferrihydrite and hematite in the lab.
- They measured light reflection (500–840 nm) and compared the data to spacecraft observations of Martian dust.
- The ferrihydrite mixture’s reflection closely matched real Martian dust, more so than hematite.
- Implications for Mars’s Past
- Ferrihydrite forms in cool water environments, meaning Mars had liquid water when this mineral formed.
- This suggests Mars was once much wetter in its ancient history.
- The ferrihydrite has remained stable under current dry Martian conditions.
(Source: Nature)
