Again Mars. This time, the publication of the photos were not from the Mars rover Curiosity, and a probe Mars Express, which is in an orbit of Mars. They were sealed riverbed Reull Vallis, once present on the surface of the red planet.
Research probe "Mars Express", a European Space Agency (ESA), at the end of last year took a picture of the Martian region called Reull Vallis with its high-resolution stereo camera. This rekoobraznaya structure. The photo clearly shows the mouth of the river dried up. Scientists suggest that in the distant past there was a river of liquid water, which had a fairly strong current. Hence, a clear trail in the photo. Under different conditions, such a trace could not be formed.
According to scientists who study the Martian surface, the river Reull Vallis previously flowed into the pool under the name of Hellas. The length of the Martian rivers Reull Vallis is about 1,500 kilometers. The width of the river is seven kilometers and a depth of about three meters.
According to the second hypothesis, the scientists, the mouth of the river could be formed during the melting of ice in the Amazonian period, and fill it with liquid water in the estuary could period Gesperiyskoy era on Mars, which ended in an interval from 3.5 billion to 1.8 billion years ago.
Planetary scientists have suggested that such rekoobraznye structure, filled with ice, may be present in the craters and other regions of Mars, and, there may be quite a lot. Space research probe "Mars Express" is going to continue to look like the river on Mars, in which many billions of years ago liquid water could flow.