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Mars has a water reservoir two-miles deep, enough to fill Earth’s Red Sea

Over a decade and a half ago, the Mars Express embarked on a journey to unravel the secrets of the Martian surface, focusing on the enigmatic Medusae Fossae Formation (MFF).

This intriguing geological feature, initially studied for its extensive deposits, has remained a subject of speculation and curiosity. But today, thanks to new research, the veil over the MFF is finally lifting.

Deep water on Mars’ Medusae Fossae Formation

Thomas Watters, from the Smithsonian Institution in the USA and lead author of both the original and recent studies, sheds light on these recent findings.

“We’ve explored the MFF again using newer data from Mars Express’s MARSIS radar, and found the deposits to be even thicker than we thought: up to 3.7 km thick,” says Watters.

“Excitingly, the radar signals match what we’d expect to see from layered ice, and are similar to the signals we see from Mars’s polar caps, which we know to be very ice rich.”

Enough water to fill Earth’s Red Sea

The implications of this discovery are profound. The ice within the Medusae Fossae Formation, if melted, could envelop Mars in a water layer measuring between 1.5 to 2.7 meters deep.

This represents the largest water reservoir discovered in this region of Mars, holding enough water to rival the volume of Earth’s Red Sea.

The Medusae Fossae Formation itself is a geological marvel, spanning hundreds of kilometers and rising several kilometers high.

It sits at the intersection of Mars’s highlands and lowlands, a potential major source of Martian dust and one of the planet’s most expansive deposits.

Earlier studies of the Medusae Fossae Formation

The initial observations by Mars Express hinted at the icy nature of the Medusae Fossae Formation due to its radar transparency and low density.

However, alternative theories proposed that the formation could be a colossal accumulation of windblown dust, volcanic ash, or sediment.

“Here’s where the new radar data comes in! Given how deep it is, if the MFF was simply a giant pile of dust, we’d expect it to become compacted under its own weight,” says co-author Andrea Cicchetti of the National Institute for Astrophysics, Italy.

“This would create something far denser than what we actually see with MARSIS. And when we modelled how different ice-free materials would behave, nothing reproduced the properties of the MFF – we need ice.”

Rewriting Martian history

The current understanding of the MFF region suggests a composition of dust and ice layers, topped by a protective layer of dry dust or ash, hundreds of meters thick.

Mars, though appearing arid now, shows signs of a water-rich past, including remnants of river channels, ancient ocean beds, and water-carved valleys.

This discovery of significant ice near Mars’s equator, like that suspected beneath the MFF’s surface, points to a radically different climatic era in the planet’s history.

“This latest analysis challenges our understanding of the Medusae Fossae Formation, and raises as many questions as answers,” says Colin Wilson, ESA project scientist for Mars Express and the ESA ExoMars Trace Gas Orbiter (TGO).

“How long ago did these ice deposits form, and what was Mars like at that time? If confirmed to be water ice, these massive deposits would change our understanding of Mars climate history. Any reservoir of ancient water would be a fascinating target for human or robotic exploration.”

Implications for future Mars exploration

For future Mars missions, the discovery of ice at equatorial locations like the Medusae Fossae Formation is invaluable.

Missions require landing near the equator, away from the polar caps or high-latitude glaciers, and water is a critical resource.

However, Wilson cautions, “The MFF deposits, buried under extensive dust layers, remain out of reach for the time being. Yet, each discovery of Martian ice enriches our understanding of the planet’s hydrological history and current water distribution.”

Mars Express continues to map water ice deep below the surface, while the Mars orbiter TGO, equipped with the FREND instrument, surveys near-surface water indications.

FREND’s detection of a hydrogen-rich area, indicative of water ice, in Mars’s Valles Marineris in 2021, and ongoing mapping of shallow water deposits, further complements this understanding.

Colin Wilson concludes, “Our collective Mars exploration efforts are progressively unveiling the mysteries of our planetary neighbor, offering glimpses into its past and potential for future exploration.”

Unraveling the secrets of Mars

In summary, the Mars Express’s recent findings on the Medusae Fossae Formation mark a significant milestone in our understanding of Mars and its climatic history.

The discovery of extensive ice deposits, challenging previous notions and revealing a potential treasure trove of water resources, enriches our knowledge of the Red Planet changes the prospects for future exploration.

These revelations bring us closer to unraveling the Martian mysteries, offering a promising outlook for both scientific discovery and the prospects of human exploration.

As we continue to explore and analyze, each piece of data adds to the intricate mosaic of Mars’s past, presenting an ever-evolving narrative of this fascinating planetary neighbor.

History of water on Mars

This study was done by the European Space Agency.


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