Where there is water, can be life, for the existence of which water is absolutely necessary - it is solvent, thanks to which it is easy to assemble complex macromolecules that are necessary for living systems. Yes, on Mars now is lots of orbital apparatus, and it is covered with geological evidence of a long-standing presence of water. But nothing more. The most encouraging to date, the conclusion is that found a place where millions of years ago flowed streams. Scientists do not stop the search. But the irony is that "just" a couple of hundred million kilometres from Mars there are a lot of potentially habitable places with plenty of water.

At least six satellites there is an underground oceans, which may be the place where the hidden life. It Europa, Ganymede, Callisto, Titan, Enceladus and Triton. Each of them can contain not less water than all the earth's oceans combined. In fact, the Earth is relatively dry planet.

The idea of the habitable zone, where the water has to remain on the surface of the planet, was proposed and popularized in the 70-ies by Michael HART. Today this concept is outdated, but he was replaced by the others. "There are other ways to become inhabited territory due to tidal interactions," says Ken Hand from the jet propulsion Laboratory of NASA.

The new paradigm is reinforced by the fact that on Earth there is also great diversity of life in extreme conditions. The so-called "extremophiles" - organisms, first appeared on Earth, will be the last surviving when other forms already become extinct.

Search samples of extraterrestrial life in the oceans is no easy task. But actually it's still easier than sending a full drilling rig and astronauts to Mars. If in the oceans of the Jupiter's satellite, Europe in any form is found life, I can firmly say that it is an inevitable stage of evolution in the Universe. If they have DNA and RNA, it is convergent evolution receives brilliant confirmation. According to it, the universe is on the same molecular pattern in the development of life, regardless of initial conditions and limitations.

The European space Agency is planning a mission to the three moons of Jupiter - Europe, Ganymede and Callisto. The work starts now, and the visit will take place approximately in 2030. In addition to this expensive project, NASA plans a study on Enceladus, "child" in relation to the space mission Stardust.

All agree that finding the life in all the richness and diversity of the oceans - it's only a matter of time.