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(Motherland) - Long ago, Mars may have resembled present-day Earth.
We are aware that Mars once possessed water bodies on its surface; indeed, liquid water existed on the planet billions of years ago. However, the specifics of where and how much water existed remain a subject of debate.
Now, by utilizing Mars' topographic data and comparing it with Earth's, researchers have been able to provide compelling evidence that about 3.5 billion years ago, Mars boasted an ocean spanning hundreds of thousands of kilometers and reaching depths of at least 900 meters.
The advantage of studying Mars is that you don't need to start from scratch: you have valuable data from another planet that you can leverage - Earth. For instance, we understand the types of geological structures and formations that water creates with rocks on Earth, so if we observe similar geological features on Mars, we can infer the presence of water there too.
Of course, not everything is as simple as that, but the guiding principle of searching for signs of ancient water on Mars bears many similarities to Earth, involving the search for structures or rocks known to be formed by water. In this case, researchers utilized software developed by the United States Geological Survey to map data from NASA and Mars Reconnaissance Orbiter's Laser Altimeter. They identified over 6,500 km of shoreline, grouping them into 20 systems, indicating that these ridges could very well be remnants of ancient coastlines, such as river deltas or submarine channel belts.
Benjamin Cardenas, assistant professor of geological sciences at Penn State and the lead author of a recent study, stated: ' One of the most significant points here is the existence of a massive ocean, which means there would be higher potential for life'.
He said: ' The rocks at Aeolis Dorsa record some intriguing information about the ancient ocean. It was very dynamic. The sea level has fluctuated significantly. The rocks were rapidly deposited along its channels. There have been many changes here'.
These maps provide evidence for a vast ancient ocean located north of Mars. Researchers mapped the location, thickness, and elevation of the mountain ridge systems to better understand the ancient geography of the area.
Essentially, the region we call Aeolis Dorsa was once a large ocean nourished by a dense network of rivers. The findings are also supported by a separate study that compared Martian terrains with seafloor terrains of the Gulf of Mexico. Researchers created an erosion basin model resembling Mars, noting that what we see on Mars is clearly indicative of a large water system.
' The stratigraphy we are explaining here is quite similar to the stratigraphy on Earth', Cardenas said. ' Indeed, it sounds like it will be a bold statement to say that we have discovered records of major waterways on Mars'.
Cardenas also added that these sedimentary records contain not only information about water on Mars but also about climate. The study's results also indicate that the planet experienced sea level rises consistent with prolonged warm and wet periods.
' It also informs us about the ancient climate and its evolution. Based on these findings, we know that there must have been a period when it was warm enough and the atmosphere thick enough to support such a large amount of liquid water at once'.
So, besides searching for something about Mars' ancient history, we also have new clues to look for signs of life. If life on Mars ever existed, and if any signs of it still exist, this ocean would be a very good place to start looking for it. In fact, Cardenas noted that some of the peaks the Curiosity rover is examining are part of this river system.
Cardenas said: ' The main goal of the Mars Curiosity exploration missions is to search for signs of life. It is always looking for water sources, traces of life that could survive'.
References: Earthlymission; Nature; NASA
