Com is growing evidence to suggest that Mars once (about 3 billion years ago) was full of water — ground water, lakes, rivers, hot springs — and, according to some models, even boasted its own ocean in the northern hemisphere.
Last hotly disputes. Even scientists who believe in the existence of the ocean, can not decide whether it was warm or cold.
Topographic map of Mars, made apparatus Mars Global Surveyor. The blue color indicates the lowest of which is likely to have been covered ocean.
New data MARSIS radar spacecraft Mars Express Orbiter, according to Jeremy Mougins University of California, Irvine (USA) and his colleagues argue in favor of Oceanus Borealis.
Radar recorded sediments in the geological region Vastitas Borealis thickness of about 100 m, which are above the volcanic rocks. It is important to note that the rate of deposition of the dielectric constant has a value of 4-5, while the volcanic rocks — 9.10 and higher. (A pure ice it equals 3.1.) Scientists believe that such a low value can be explained only by the deposition of a wide aquatic sediment or sediment, mixed with plenty of ice.
Answering yes to the question of the existence of an ancient ocean, can not escape from the following problem: what happened to the water? Mars Express data suggests that beneath the surface buried vast reserves of water ice — in particular at the poles, and in the vicinity of a hypothetical ocean coastline, and even closer to the equator than expected.
We should also mention that the lander Phoenix, who sat in the Vastitas Borealis in 2008, has found deposits of water ice just a few inches under the ground.