A study led by researchers at Brown University (United States) Presentations New insights into how water from melting ice plays a recent role in the formation of canyon-like channels that cut the sides of the impact craters Mars.
The study published in the journal Sciencesfocuses on the valleys of Mars that have Eerily similar to the valleys that form on Earth in the Dry Valleys Antarctica which is caused by water erosion from melting glaciers.
Including researchers Jim HeadBrown’s Planetary Scientist created a model that simulates the optimum point at which conditions on Mars allow the planet to warm above freezing temperatures, leading to periods of liquid water on Mars When the ice melts above and below the surface.
They discovered that when Mars is tilted on its axis up to 35 degrees, The atmosphere becomes dense enough for them to occur Short episodes of melting in places where valleys are located.
Then they compared the data from their model to the periods in Mars’ history when the planets are thought to have Valleys of the Terra Sirenum region From the planet rapidly spreading slopes of heights, An inexplicable phenomenon without the occasional presence of water.
“We know this from a lot of our own and others’ research Early in the history of Mars, there was running water on the surface with networks of valleys and lakesexplains Head, professor of geosciences at Brown University.
“but About 3 billion years ago, all that liquid water was lost and Mars became what we call an extremely dry desert, or polar desert. -Add-. We show here that even after that and in the recent past when the axis of Mars was tilted by 35 degrees, It gets hot enough to melt snow and icereturn liquid water Until temperatures drop and freeze again.”.
Similar features in Antarctica
Results help Fill in some of the missing gaps about how these valleys form, including the altitude at which to start, the severity of erosion, and how far the excavation slope is. According to previous theories, the valleys of Mars were formed by Frost carbon dioxide, which evaporates from the ground and causes rocks and debris to slide down the slopes.
the valleys height It has led many scientists to theorize that meltwater from glaciers must be involved because of the distance they travel down the slopes and the appearance of eroded valleys. Proving the existence of liquid water on Mars since it disappeared long ago has been difficult. Because temperatures are usually around minus 70 degrees.
The results of the new study indicate that the formation of the groove was due to Periods of thawing and evaporation of carbon dioxide frosts at other times of the year. According to the researchers, it is likely that this phenomenon has been repeated over the past few million years The most recent one is about 630,000 years ago.
They claim that if there were ice in the canyons in the regions they analyzed when the axis of Mars was tilted about 35 degrees, then Suitable for melting ice because temperatures rose above 273 degrees Kelvinwhich is equivalent to about zero degrees Celsius.
“Our study shows that the global distribution of grooves The best explanation for this is liquid water over the past million years -Highlights Jay Dixonlead author of the study and a former Brown researcher now at Caltech. Water explains the height distribution of the canyons in a way that CO2 cannot. This means that Mars was able to produce liquid water in sufficient quantities to erode the channels in the past million years, ie Very recent on the scale of Mars’ geological history“.
Although skeptical that meltwater was possible and scientists have never been able to engineer the right conditions on Mars for ice to melt, The researchers were convinced that the meltwater theory was accurate because they had seen similar features firsthand in Antarctica. There, despite the low temperatures, The sun is able to heat the ice enough to melt and gully activity to occur.
The new study is a continuation of previous research the team began decades ago on the valleys of Mars. In a 2015 study, for example, researchers showed that In the past it was possible that there were periods on Mars when water was available to form gullies if Mars was tilted enough on its axis.
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