American astronomers report that they have discovered a new stash with significant reserves of water ice, lying at a depth of about five kilometers under the surface of the North pole of Mars. Scientists believe that this ice is a remnant of ancient polar ice shields and is the largest accumulation of water on Mars. About his discovery, the researchers reported in an article published in the journal Geophysical Research Letters.
To make a discovery the team of scientists from Texas and Arizona universities helped the SHARAD radar (Shallow Subsurface Radar) mounted on orbital and interplanetary spacecraft NASA’s Mars Reconnaissance Orbiter, which is located at the red planet since 2006 and to date has completed 60 000 orbital overflights of our planetary neighbor. The radar operates in the frequency band from 15 to 25 MHz and is able to collect data on the structure of the Martian subsurface to a depth of more than 2.5 kilometers. The device was developed by scientists of the Italian space Agency. He showed that in some strata under the North pole amount of ice reaches 90%. Observations of radar have been analyzed and tested in independent studies using gravity data.
“We didn’t expect to find there is so much water ice. This probably makes it the third largest accumulation of water on Mars after the polar ice caps,” — says the opening of the study’s lead author, Stefano Nerozzi from the Institute of Geophysics of the University of Texas.
Stock is really huge, the researchers note. They explain that if that ice melts, then the whole of Mars is covered with a water layer, to a depth of half a meter.
The researchers suggest that the layers were formed when the ice accumulated at the poles of Mars during the last glacial periods, millions of years ago. Every time a planet is heated, the remnants of the ice caps covered with sand, which protected the ice from solar radiation and prevented its dissipation into the atmosphere.
Scientists have long known that the history of Mars occur periodically ice ages caused by variations in its orbit and tilt of axis. About every 50 thousand years the planet tilts toward the Sun, and then gradually returns to its upright position. When the axis of the vertical rotation of the planet closest to the Sun are the Equatorial region and at the poles may contain ice. When Mars is tilted, ice caps are gradually reduced and may disappear completely. But until now it was thought that no evidence of previous glaciation is not preserved.
The researchers note that the study of the structure and composition of these frozen sediments will help to establish what was the climate of Mars in the distant past, as well as to provide a more comprehensive mapping of water resources of the planet. This information can be very important, not only because in the future, mankind is planning to colonize this planet, but also because the presence of water may indicate the presence of traces of life on the red planet.
“If we want someday to get water on Mars, very important for us to understand what it stocks in the past was available on the planet on a global scale, and how much of it could be preserved in its polar regions. You can have all the favorable conditions for the existence of life, but if the main water reserves are concentrated at the poles, for life that could exist closer to the equator, there may be a deficiency of it,” says Prozzi.