Large amounts of water ice have been discovered at the equator

More than 15 years ago, the Mars Express probe was launchedEuropean Space AgencyEuropean Space Agency (European Space Agency) Notice the training Medusa fossilsLocated inequatorequator From the planet. This region of Mars is known to be the largest sedimentary deposit on the planet. It extends intermittently over more than 5,000 kilometers, covers an area equivalent to the size of India, and consists of several geological structures carved by windswinds It is hundreds of kilometers in diameter and several kilometers in height. These formations lie on the border between the Martian highlands and lowlands, and are perhaps the largest source of dust on Mars and one of the largest sources of dust on Mars. DepositsDeposits The most comprehensive on the planet.

The mysterious nature of the sediments beneath the Medusae Fossae Formation

Radar data at the time revealed huge deposits up to 2.5 kilometers deep. But the data was not clear enough to determine exactly what material it was made of. If we assume that these could be glacial deposits, scientists have not ruled out that they are in fact giant accumulations of dust, volcanic ash or volcanic rocks. SedimentsSediments In the wind.

In 2023, the same team observed this interesting region of Mars again. I have reached a conclusion that leaves no doubt about the nature and composition of these subterranean deposits.

Using new data from the Marsesian radar, scientists discovered that deposits… Medusa fossils : ” It was thicker than previously thought: up to 3.7 kilometers thick “, explains Thomas Waters of the Smithsonian Institution, the lead author of both studies. I add, ” Interestingly, the radar signals match what we expect from ice sheets and are similar to the signals we see from them Polar caps of MarsWhich we know is very rich in ice “. the New results Instead they indicate layers of dust and ice, all topped with a protective layer of dry dust or ash several hundred meters thick.

Huge amounts of water

We're talking about a huge amount of ice. In fact, if all the ice surrounding it melted, it would cover the entire planet in a layer of water between 1.5 and 2.7 meters high: the largest amount of water ever found in this part of Mars, and enough to fill Earth's Red Sea. This new data also casts doubt on the 2007 conclusions. Given the density of the sediments underneath Medusa fossils“If it's just huge piles of dust, volcanic ash or sediment carried by the wind,” We expect them to collapse under their own weight“, explains co-author Andrea Cicchetti from the National Institute of Astrophysics in Italy. This would create something much denser than what we already see MarsisMarsis. And when we modeled the behavior of different materials without ice, there was nothing that replicated the compositional properties of Medusae fossils: we needed ice. »

New implications and issues in the history of the water cycle on Mars

Although Mars now appears to be a barren world, the planet's surface is littered with signs that water was once abundant, including dried-up river channels, ancient ocean and lake bottoms, and valleys carved by water. We've also discovered large reserves of water ice on Mars, such as these Polar hatsPolar hatsthe GlaciersGlaciers Buried near the equator and near-surface ice embedded in Martian soil.

Unsurprisingly, this latest analysis It challenges our understanding of the composition of Medusae Fossae and raises as many questions as answers “, says Colin Wilson, ESA mission scientist Mars ExpressMars Express Orbital gas tracking. “If it's water ice,” These massive deposits would change our understanding of Mars' climate history and would be a fascinating target for human exploration RoboticsRobotics From March “As for those searching for where the water that flowed on Mars went, these sediments are part of the answer!

Although Mars appears barren today, the discovery revives interest in the planet's past waters and raises questions about its climate history. However, these deposits buried under hundreds of meters of dust and sediment are currently inaccessible, and represent a challenge for future research.