Canadian Astronomers Have Found Traces Of The Oldest Glaciers On Mars
After analyzing tens of thousands of photos of the surface of Mars, Canadian planetary scientists found many traces of ancient glaciation. This discovery suggests that there was practically no liquid water on Mars in the first epochs of its existence. The results of the scientists' work are available in the scientific journal Nature Geoscience.
"This is the first time we have found traces of water erosion on the surface of Mars. The water that caused them moved through channels under the surface of Martian glaciers. Moreover, our observations show that only a small part of the Martian valleys owe their appearance to rivers. This radically contradicts the established ideas about their origin," said one of the authors of the work, a Professor at the University of British Columbia (Canada) A. Mark Jellinek.
Now, most planetary scientists assume that in the first epochs of its existence, Mars was very similar to Earth. At that time, it had a thick atmosphere, oceans of water, and a fairly mild climate, meaning the planet was potentially suitable for the origin of life.
However, such conditions existed on Mars for a relatively short time, about a billion years after its formation. At the beginning of the so-called Hesperian era, about 3.6 billion years ago, it turned into a lifeless desert. Almost the entire atmosphere of the planet and its water reserves have disappeared into space or turned into ice reserves.
No less controversial is where these moisture reserves came from on Mars and what the planet looked like immediately after it appeared. The fact is that climate models and other calculations show that Mars was originally too cold for permanent rivers, lakes, and oceans to exist on its surface. This, however, is not combined with the fact that on its surface there are many traces of such reservoirs, including in the form of channels and river valleys.
The oldest Martian glaciers
Professor Jellinek and his colleagues have found a possible explanation for why the results of climate modeling and photos of the actual surface of Mars are not similar to each other. In the latest study, they examined tens of thousands of photographs of so-called "valley networks." This is what scientists call the many small channels connected that were first discovered by the Viking probes in the late 1970s.
All of these channels are mostly concentrated on high ground in the southern hemisphere of Mars. Analysis of the images showed that they originated in the first epochs of the planet's life, from 3.9 to 3.5 billion years ago. Today, scientists debate exactly how they originated, but almost all planetary scientists believe that they were left by surface streams of liquid water.
Canadian researchers have questioned this, noting that many "valley networks" are almost indistinguishable in shape and shape from what the shores of Devon Island in the Canadian Arctic look like, cut by similar channels. After studying their structure in detail, and comparing it with the structure of the Earth's river valleys, scientists have created an algorithm that can determine the type of erosion that generates such landforms.
Using this program, Yellinek and his team analyzed the appearance of thousands of other similar structures on Mars from images taken by the Mars Global Surveyor probe. It turned out that more than half of the Martian "networks of valleys" were generated either by the movement of glaciers or by flows of meltwater under their surface.
This, in turn, suggests that during the supposedly warmest epoch of its existence, when the planet's atmosphere had not yet escaped into space, a significant part of the surface of Mars was covered with glaciers. In other words, there is no contradiction between climate calculations and images of the planet's surface.
Such ice masses and the liquid water hidden under them, as Jellinek and his colleagues suggest, could serve as the last shelters of life on Mars since a thick layer of ice protected the inhabitants of these subglacial reservoirs from low temperatures and cosmic rays. This makes them a promising target for future missions that will study the Red Planet, scientists believe.