Newly discovered icebergs buried a mile below Mars & # 39; the North Pole is the remains of ancient ice beams and could be one of the largest reservoirs on the planet, according to researchers at the University of Texas at Austin and the University of Arizona.
The team made the discovery using measurements collected by Shallow Radar (SHARAD) on NASA's Mars Reconnaissance Orbiter (MRO). SHARAD emits radar waves that can penetrate up to half and a half below the Mars & # 39; surface.
The results published on May 22 in Geophysical Research Letters are important because the battles are a record of the former climate on Mars in the same way as the tears are a record of past climate on Earth. Studying the geometry and composition of these layers could tell researchers whether climatic conditions were previously beneficial to life, researchers said. The team found layers of sand and ice that were as much as 90% water in some places.
If melted, the newly discovered polar ice would correspond to a global layer of water around Mars at least 1
"We do not expect to find this much water ice here," said lead author Stefano Nerozzi, a research assistant at the University of Texas Institute for Geophysics (UTIG), who conducts his Ph.D. at the Jackson School of Geosciences. "It probably makes it the third largest reservoir on Mars after the polar ice."
The results were confirmed by an independent study using gravity data instead of radar, led by researchers at Johns Hopkins University. Nerozzi was co-author. The papers have been published simultaneously in Geophysical Research Letters .
The authors believe that the layers are formed when the ice accumulates at the poles in earlier ice age on Mars. Every time the planet warms, a remnant of the ice caps were covered with sand, which protected the ice from sunlight and prevented it from spreading into the atmosphere.
Scientists have long been aware of ice events on Mars, which are driven by variations in the planet's orbit and tilt. Over periods of about 50,000 years, Mars leans toward the sun before gradually returning to an upright position as a wobbling spinning top. When the planet jumps upright, the equator turns toward the sun so that the polar ice caps can grow. As the planet overturns, the ice caps pull back, perhaps they disappear completely.
So far, the researchers found that the old ice caps had been lost. The paper shows that, in fact, significant ice sheet residues have survived below the surface of the planet, trapped in alternating ice and sand bands, such as layers on a cake.
Co-author Jack Holt, professor at the Lunar & Planetary Laboratory of the University of Arizona, said the study provides new important insights into the exchange of water ice between the poles and midlatitudes, where his research group previously confirmed the prevalence of widespread glaciers, including using the SHARAD instrument.
"Surprisingly, the total amount of water that is locked in these buried polar deposits is basically the same as all the water known to exist in glaciers and buried ice at lower latitudes on Mars, and they are about same age, "he said. 19659003] Holt, a UTIG researcher and research professor for 19 years before joining the University of Arizona in 2018, has been a co-researcher with SHARAD since the spacecraft arrived in Mars in 2006.
Nerozzi said that studying This record of former polar glacier could help determine if Mars was ever habitable.
"Understanding how much water was available globally to what is caught in the poles is important if you are to have floating water on Mars," said Nerozzi. "You can have all the right conditions for life, but if most of the water is locked in the poles, it will be difficult to have sufficient amounts of liquid water near the equator."
The study was supported by a grant from the NASA Mars Data Analysis Program and the MRO Project Office at Jet Propulsion Laboratory. SHARAD was delivered to NASA's MRO mission by the Italian Space Agency.