Why is Mars red? A new study revealed by NASA & ESA

Mars, often referred to as the Red Planet, has long intrigued scientists due to its striking rusty hue. Previously, researchers believed that Mars turned red through a slow oxidation process in dry conditions over billions of years. However, new findings combining data from European Space Agency (ESA) and NASA missions with advanced laboratory experiments suggest a much wetter origin for Mars’s iconic colour.

Why is Mars red?

The study reveals that ferrihydrite, a water-rich iron mineral, is likely responsible for Mars’ reddish hue. Findings suggest that Mars had a climate capable of sustaining liquid water billions of years ago and an iron oxide that forms rapidly in the presence of water. The research combines data from NASA and ESA missions with laboratory simulations to test the hypothesis. The results open new possibilities for understanding Mars’ climate history and habitability.

Source: esa

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Mars’ Climate: Then vs. Now

What is the Role of Water in Mars’s Rusty Appearance?

Recent research has challenged the long-held assumption that Mars’s red colour is solely due to haematite, an iron oxide formed in dry conditions. Instead, a new analysis points to ferrihydrite, an iron oxide that forms rapidly in the presence of water. This discovery suggests that Mars underwent oxidation much earlier, during a period when liquid water was abundant on its surface.

Comparison of Martian Iron Oxides

Role of Ferrihydrite in Mars’ Red Color

Research published in Nature Communications suggests that ferrihydrite, an iron oxide mineral, played a crucial role in giving Mars its iconic red appearance. Unlike haematite, which was previously considered the main contributor, ferrihydrite forms at lower temperatures and in the presence of cool water.

Source: esa

How Did Scientists Recreate Martian Dust?

To validate their findings, researchers conducted controlled laboratory experiments simulating Martian dust. They used advanced grinding techniques to create dust particles as small as 1/100th of a human hair, mimicking real Martian conditions. By analysing these samples using the same methods employed by orbiting spacecraft, scientists confirmed that ferrihydrite provided the best match to Mars’s actual dust.

Laboratory experiment steps:

• Creating Martian Dust Simulants: Scientists mixed ferrihydrite with basalt, a volcanic rock found on Mars.

• Dust Particle Analysis: The samples were analysed under controlled conditions to match spacecraft observations.

• Comparing with Mars Data: The results were compared with ESA’s Trace Gas Orbiter (TGO) and NASA’s Mars Reconnaissance Orbiter data.

Spacecraft Observations Confirm Findings

A wealth of data from past and current Mars missions supports this groundbreaking discovery:

• ESA’s Mars Express & TGO: Provided mineralogical analysis, revealing water-rich minerals in even the dustiest regions.
• NASA’s Mars Rovers (Curiosity, Pathfinder, Opportunity): Contributed ground-based insights into the iron oxide composition of Martian dust.
• NASA’s Perseverance Rover: Has collected dust samples, which may soon confirm the presence of ferrihydrite.

Significance of the Discovery

• Mars rusted earlier than thought, implying the planet had liquid water longer than previously assumed.
• Ferrihydrite’s stability in present-day Martian conditions supports the hypothesis that ancient water still influences Mars’s surface properties.
• New missions, such as ESA’s Rosalind Franklin Rover and the Mars Sample Return mission, will provide deeper insights into the Red Planet’s history and its potential for past life.

Why This Discovery Matters:

• Evidence of Water: The presence of ferrihydrite indicates prolonged water activity.
• Past Habitability: Suggests an environment more suitable for sustaining life.
• Climate Insights: Helps reconstruct Mars’ transition from a wet to a dry planet.

Expert Perspectives

As per Adam Valantinas, Lead Author, Brown University “The widespread presence of ferrihydrite in Martian dust and rocks, formed under wet conditions, provides strong evidence to answer the centuries-old question of why Mars is red.” 

“These findings highlight the value of collaborative research between NASA and international partners in addressing fundamental questions about our solar system.” according to Geronimo Villanueva, NASA’s Goddard Space Flight Center

Future Exploration: Unlocking Mars’s Secrets

The upcoming NASA-ESA Mars Sample Return mission will allow scientists to analyse dust samples directly on Earth. These findings will refine our understanding of Mars’s climatic history, water availability, and habitability.

What’s Next?

• Mars Sample Return Mission: Expected to bring back Martian dust samples for detailed analysis.
• Rosalind Franklin Rover (ESA):  Will explore subsurface layers to uncover more about Mars’s ancient environment.
• Continued Mars Orbiter Studies: Future spacecraft will further refine our understanding of Martian minerals.

Conclusion

While Mars’s red hue remains a striking feature of our solar system, its origins may be different from what we once believed. The discovery of ferrihydrite in Martian dust suggests a wetter and more dynamic history, altering our perspective on the planet’s evolution and its potential for past life. As new missions continue to unveil the Red Planet’s mysteries, one thing is certain: Mars still has many secrets waiting to be discovered.

Stay tuned for more updates as scientists continue to explore the mysteries of Mars!