Some marks on the surface of Mars that look like riverbeds, could leave the melt water under the ice sheets, not free flowing river, as previously thought. To such conclusion scientists have come, having compared the topography of the planet with ice-channels of Devon island in the canadian Arctic. Article published in the journal Nature Geoscience.
Scientists today have no clear understanding of what were the climatic conditions on Mars billions of years ago. Some terrain features of the planet indicate that in the past on its surface could exist an extensive network of rivers and lakes. However, how they appear, researchers are not clear, because then the young Sun emitted about 30 percent less energy, and given the fact that Mars is even further than Earth, water it was just freezing.
Anna Grau Galore (Anna Grau Galofre) from the University of British Columbia, along with colleagues suggested in a new article that at least part of the rivers on the red planet could be formed under the protection of the ice cover. This hypothesis of the researchers was born during a study of the major desert of Devon island, which is a cold polar desert and is considered one of the closest analogues of Mars on Earth. Until recently, it was covered with a thick layer of ice but now the ice had retreated from the Western part of the island, revealing a network of channels that form was very similar to some rivers dried up riverbed on the red planet.
To check, could on Mars 4 billion years ago to flow ice rivers, scientists relying on computer models, analyzed images of the surface of the planet obtained by the Mars Global Surveyor probe. They studied 66 networks of valleys and divided them into groups depending on complexity of drainage network length and channel width of the channels. In the study, geologists noticed that some of the valley looks like the river they flowed into the mountain. According to scientists, this is possible if the water is under the ice that much pressure on it and forces to change the direction of flow.
Based on this observation and on physical models, the group Galore came to the conclusion that not all networks of valleys on Mars formed through the same processes: while some of them were really born surface river runoff, more than half were formed under a thick ice cover.
This discovery may have great importance in the evaluation of viable ancient Mars. It is believed that the unstable young Sun could pass through periods of very powerful radiation that could harm the primitive organisms, and if part of the red planet was indeed covered with a thick layer of ice, it could serve as protection for a hypothetical life.
Recently astronomers have proposed an explanation for the paradox of the young Sun, which is that, despite the fact that it is radiating less energy, the climate on the ancient Earth was warm and humid. The researchers concluded that mild temperatures on our planet helped to maintain a powerful coronal mass ejection.