Soil and water

Scientists find water in the Grand Canyon of Mars


This is the massive Valles Marineris canyon system on Mars as seen by ESA’s Mars Express Orbiter. It is approximately 10 times longer and 5 times deeper than our terrestrial Grand Canyon. The European-Russian orbiter Trace Gas Orbiter (TGO) has found traces of water at the bottom of Valles Marineris. The water in the Grand Canyon of Mars is probably in the form of ice near the surface. The water in the canyon of Mars is a surprise to scientists. Image via ESA / DLR / FU Berlin (G. Neukum) / CC BY-SA 3.0 IGO.

Water in Grand Canyon of Mars

Arizona’s Grand Canyon is one of the most famous geological features on the planet. Water once rushed there, creating the system of deep, massive canyons we see today. Now a satellite has found evidence of water in the Grand Canyon’s own version of Mars, scientists said on December 12, 2021. The European-Russian orbiter Trace Gas Orbiter (TGO), which is part of the ExoMars mission , found this groundwater in Valles Marineris. Scientists have said that the water is most likely in the form of ice.

The researchers published the new peer-reviewed findings in the journal Icarus November 19, 2021. March 1, 2022, tome de Icarus will also include paper.

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Discovery surprised scientists

TGO found the water using its FREND instrument (Fine Resolution Epithermal Neutron Detector). The spacecraft uses FREND to map the amount of hydrogen (a major component of water) in the immediate subsoil of the planet. The discovery of the water was surprising, as it shows that there is much more water in the basement below the canyon floor than expected.

The water-rich area in the central part of the Candor Chaos canyon is about the size of the Netherlands. It turns out that the material near the surface in this region contains about 40% water. Igor Mitrofanov of the Institute for Space Research of the Russian Academy of Sciences in Moscow and lead author of the new study, said:

With TGO, we can look up to a meter below this dusty layer and see what is really going on beneath the surface of Mars and, most importantly, locate water-rich “oases” that could not be detected with previous instruments. FREND revealed an area with an unusually high amount of hydrogen in the colossal Valles Marineris canyon system: assuming the hydrogen we see is bound to water molecules, up to 40% of the matter near the surface in this region appears to be water.

Map of the crater landscape with blue, red, yellow, and purple regions, the areas labeled A, B, and C.
See bigger. | This map shows the area of ​​hydrogen (water) in the central region of Valles Marineris. “C” indicates the water-rich region. Image via I. Mitrofanov et al. (2021) / ESA.

Mapping hydrogen with neutrons

So how did TGO find out about water? He used his FREND instrument to map the hydrogen content of Martian soil just below the surface. It does this by detecting neutrons rather than using light. Co-author Alexey Malakhov said:

Neutrons are produced when highly energetic particles known as “galactic cosmic rays” hit Mars; drier soils emit more neutrons than wetter ones, so we can infer the amount of water in a soil by looking at the neutrons it emits. FREND’s unique observation technique provides much higher spatial resolution than previous measurements of this type, now allowing us to see aquatic features that had not been spotted before. We found a central part of Valles Marineris filled with water, much more water than expected. It looks a lot like the permafrost regions of Earth, where water ice permanently persists under dry ground due to the constant low temperatures.

But what type of water in the Grand Canyon of Mars?

Another question is what form the water is in. Is it liquid, icy or chemically bound to the ground? Right now, researchers believe it’s most likely ice, according to Malakhov:

Overall, we believe this water is more likely to exist in the form of ice.

Men in dark suits chat across a conference table with a white-haired man in a lighter suit.
Igor Mitrofanov (right) meets with ESA leaders on August 25, 2015, at the MAKS international aviation and space fair. Mitrofanov is the lead author of the new water study at Valles Marineris. Image via ESA / Stéphane Corvaja (2015).

However, there must be some unique conditions that allow water ice to stay there. This is because water ice or even bound water usually evaporates as close to the equator, where the canyon system is located. Only the right combination of temperature, pressure and hydration can prevent water from disappearing. It is also possible that something will replenish the water, although it is not known how this would happen.

Final confirmation that the water is indeed ice will require additional observations, however. As co-author HÃ¥kan Svedhem said:

This discovery is an amazing first step, but we need more observations to know for sure what form of water we are dealing with. Whatever the outcome, the discovery demonstrates the unparalleled abilities of TGO instruments to allow us to “see” beneath the surface of Mars and reveals a large reservoir of not too deep and easily exploitable water in this region of Mars.

Indices of habitability and life on Mars

Of course, the discovery of water also evokes the possibility of life, past or present. This water may come from when Mars had abundant water on its surface a few billion years ago.

Bird's eye view of the reddish terrain with valley and cliffs.
Perspective view of Candor Chasma in the central area of ​​Valles Marineris. This is where the groundwater was found. Image via ESA.

Colin Wilson, scientist for the Trace Gas Orbiter project, said:

This result really demonstrates the success of the joint ESA-Roscosmos ExoMars program. Learning more about how and where water exists on Mars today is essential to understanding what happened to the once abundant water on Mars, and helps our search for habitable environments, possible signs of past life. and organic materials from the first days of Mars.

Could this water even support microorganisms today? No one knows for sure, but it’s a tantalizing thought. It would be better if the water was liquid and not frozen, but even then it is conceivable that some types of extremophile-like organisms could still use it.

Resource for future human exploration

When human astronauts finally arrive on Mars, water will of course be the primary resource needed. Being so close to the surface means that this water could be used to support human expeditions. Water frozen in the ground, like permafrost on Earth, could easily be turned into liquid water.

It would be easier than trying to use ice found at the planet’s poles or deeper underground. There may also be liquid water below the surface of Mars, but it is probably even deeper and more difficult to access.

Spaceship with solar panel and large satellite dish above the reddish planet.
Artist’s illustration of the European-Russian orbiter Trace Gas Orbiter (TGO), which has been orbiting Mars since 2016. Image via ATG medialab / ESA.

The largest canyon in the solar system

Valles Marineris is a massive feature of the Martian landscape, eclipsing the Grand Canyon on Earth. In fact, it’s about ten times longer and five times deeper than the Grand Canyon. It is approximately 2,500 miles (4,000 km) long and reaches depths of up to 4 miles (7 km). Imagine standing on the edge and looking through this giant chasm …

The existence of water at Valles Marineris will also help scientists better understand what happened to all the water that existed on the surface of Mars. Where did it all go? Is most of it underground now? Wilson said:

Learning more about how and where water exists on Mars today is essential to understanding what happened to the once abundant water on Mars, and helps our search for habitable environments, possible signs of past life. and organic materials from the first days of Mars.

Conclusion: European-Russian orbiter Trace Gas discovered groundwater ice at Valles Marineris on Mars, the largest canyon system in the solar system.

Source: Evidence of unusually high hydrogen abundances in the central part of Valles Marineris on Mars

Via ESA