The mystery of Mars and water has a new chapter. The missions like Curiosity in the Gale crater they show clear evidence for the existence of liquid water lakes for thousands or millions of years. That climate models show that the early Mars It was a cold place. with temperatures significantly below the freezing point, it was elucidated with seasonal ice shields. However, among the pending subjects of Mars astronomy is knowing how much there was water and when was there.
Mars was (half) blue. A recent study published in the scientific journal npj Space Exploration echoes the discovery of a “tide line” that explains that there was once an interconnected water system. Ignatius Argadestya, the lead author of the study, explains that although today Mars is a dry and reddish planet: “our results show that in the past it was a blue planet similar to Earth.”
In fact, they have been able to demonstrate the existence of the deepest and most extensive ocean that has existed on Mars to date, account the scientist that half the red planet was once blue: “an ocean that extended across the planet’s northern hemisphere.”
Valles Marineris in Hi-Res
The “deltas” of Mars. More specifically, they have investigated geological formations called deposits with steep front located in the region of Valles Marineristhe largest canyon system in the solar system. Using very high resolution images from Cassis of the European Space Agency and the CTX and HiRISE from NASA (the latter provides a maximum resolution of about 25 to 30 centimeters per pixel), have been able to identify these deposits with identical morphology to the river deltas that we see in rivers such as the Ebro or the Danube when they flow into the sea.
Thus, on Mars there was a time when water flowed from the mountains through branching channels until it reached a kind of lake or sea, where sediments were deposited. These deltas end in an abrupt step that is located at exactly the same altitude at different points on the planet, between -3750 and -3650 meters with respect to the reference level of Mars.
About 3.37 billion years ago. This is not a geological coincidence, it is that at one time there was a body of water like a sea that maintained a stable level for a long time: it is a mark of the shore of a primeval Mars, since these deposits were formed between the Late Hesperian and Early Amazonian periods. According to the research team, that was the time in the history of Mars with the greatest availability of liquid water on its surface.
Why is it important. Already had applied previously the existence and size of this Martian ocean, but its conclusions come with more precise and direct evidence. In addition, they have been able to determine when the water peak occurred on Mars. The deltas found constitute a magnificent base to study their sediments in depth in search of traces of life because where there is water, there could be life.
On the other hand, among the next steps is to understand how Mars went from having an ocean that occupied half the planet to being a frozen desert. In fact, there are already clues: the research team detected desiccation cracks and dunes on these channels, which indicates that after this aquatic period, there was a progressive drying until they became arid.
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Cover | Javier Miranda
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