{"id":36191,"date":"2026-09-03T10:15:00","date_gmt":"2026-09-03T14:15:00","guid":{"rendered":"https:\/\/www.ecoticias.com\/en\/?p=36191"},"modified":"2026-09-03T06:59:02","modified_gmt":"2026-09-03T10:59:02","slug":"nasas-radar-searched-for-mars-buried-lake-beneath-the-south-pole-and-the-weak-echo-has-made-the-water-mystery-harder-to-believe","status":"publish","type":"post","link":"https:\/\/www.ecoticias.com\/en\/nasas-radar-searched-for-mars-buried-lake-beneath-the-south-pole-and-the-weak-echo-has-made-the-water-mystery-harder-to-believe\/36191\/","title":{"rendered":"NASA\u2019s radar searched for Mars\u2019 buried lake beneath the south pole, and the weak echo has made the water mystery harder to believe"},"content":{"rendered":"\n

For many years, one of the most fascinating mysteries of Mars was hidden beneath the ice of its south pole. In the year 2018, a radar of the European Space Agency<\/a> found an unusual, bright reflection, located around 0.9 miles below the surface. This could mean that there was a lake of salty liquid water<\/a>, approximately 12 miles wide.<\/p>\n\n\n\n

Now, a different radar has studied that area, but what it found is not so impressive. NASA\u2019s SHARAD instrument<\/a> only detected a low echo, so this made it less likely to be a body of liquid water, although researchers are still not able to confirm what lies under the ice.<\/p>\n\n\n\n

Why they believed there was water<\/h2>\n\n\n\n

This conclusion came from MARSIS<\/a>, a radar instrument carried by ESA\u2019s Mars Express spacecraft. Scientists studied 29 observations<\/a> made between 2012 and 2015 near Ultimi Scopuli, an area within the layered deposits that surround the south pole.<\/p>\n\n\n\n

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Read More: NASA\u2019s radar searched for Mars\u2019 buried lake beneath the south pole, and the weak echo has made the water mystery harder to believe<\/a><\/h4>\n<\/div>\n<\/div><\/div>\n<\/div>\n\n\n\n

MARSIS used low-frequency radio pulses that were sent through thick ice<\/a> and dust. In an area about 12 miles wide, the radar detected some echoes beneath the ice that were stronger than the ones that came from the surface. On Earth, patterns like this one, generally indicate that there is subglacial water.<\/p>\n\n\n\n

Because liquid water has very different electrical properties from ice and many rocks<\/a>, the team believed that the most logical explanation was the presence of salty water, but at the same time, radar evidence is not a photograph or chemical confirmation of a lake.<\/p>\n\n\n\n

NASA\u2019s radar needed a rare maneuver<\/h2>\n\n\n\n

NASA\u2019s Mars Reconnaissance Orbiter<\/a> has an instrument called SHARAD, which works at a higher frequency than MARSIS. It can detect thinner layers, but the problem is that its signal loses more energy as it passes through polar ice.<\/p>\n\n\n\n

\"NASA
An illustration shows NASA’s Mars Reconnaissance Orbiter using SHARAD radar to probe beneath the Martian surface, where reflections can reveal buried layers and structures.<\/figcaption><\/figure>\n\n\n\n

To improve the signal and obtain better results, NASA rotated the spacecraft approximately 120 degrees, so it would not be on the antenna\u2019s way. This improved the signal, making it at least ten times stronger, although this was a risky move that could only be made with carefully controlled conditions.<\/p>\n\n\n\n

No bright echo<\/h2>\n\n\n\n

SHARAD managed to reach the base of the ice but just recorded only a very weak return from the possible lake. Researchers did not expect that the instruments would produce identical results because they use different frequencies and they process data in a different way.<\/p>\n\n\n\n

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Read More: NASA still has no year for the first human Mars landing, and the missing date reveals why the real countdown has not begun<\/a><\/h4>\n<\/div>\n<\/div><\/div>\n<\/div>\n\n\n\n

If there was a lake, it would have appeared in SHARAD\u2019s data. If there was a flat layer of liquid water, it would have been detected. One possibility is that the ice present above the suspected lake absorbed the high-frequency signal.<\/p>\n\n\n\n

Other materials may seem like water<\/h2>\n\n\n\n

Radar brightness does not automatically mean there is one specific material. It could also come from rock, conductive minerals, thin layers, or variations in the amount of ice and dust content.<\/p>\n\n\n\n

Another obstacle is temperature. Beneath the polar cap, temperatures are believed to be below the normal freezing point of water. An explanation for a large underground lake to remain liquid would be if the water were extremely salty or if Mars supplied more geothermal heat<\/a> than expected.<\/p>\n\n\n\n

Previous surveys also found bright reflections<\/a> in parts where the ice seemed to be too cold or too shallow for melting. This made researchers think that these \u201cwater\u201d echoes could have another cause. The latest results of SHARAD give scientists another reason to consider this explanation.<\/p>\n\n\n\n

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