We will see that liquid water is probably present in the Galaxy, perhaps even more than our solar system suggests with planets like Mars, the object of all fantasies since the formulation of the hypothesis of life on Earth March. On the other hand, if the presence of liquid water is a necessary condition for the appearance of life, it certainly does not appear to be a sufficient condition.

It must already be remembered that only liquid water has an interest: water ice or water vapor have no particular value for life. In fact, the interest of liquid water lies in its ability to promote chemical reactions.

Living beings consist of an orderly arrangement of incredibly complex molecules: to create such structures, simple organic molecules had to react chemically together, in order to grow and transform. So it took a very special environment to allow these reactions to happen.
Are all liquids the same from the point of view of chemistry? Far from there ! Suppose we want to mix two species together in a liquid such as oil, to make them react. The heavier species tends to settle at the bottom, while the lightest tends to float. Finally, the two species remain separated and can not react effectively.
Now mix these two species in water. The molecule of water has an interesting property: it has a positively charged side, and the other negatively charged. It is said to be a "polar" molecule.
Thanks to the electrostatic attraction due to these charges, it tends to "stick" to many other species.
Thus, if we put alcohol in water, the water molecules will be eager to surround each molecule of ethanol: alcohol is dissolved in water. Although it is lighter than water, the alcohol does not float above it: a unique mixture of water and ethanol appears, each molecule of ethanol being closely "glued" to the water molecules. If this were not the case, the first to open a bottle of wine would drink pure alcohol, while the following would be satisfied with the juice of grapes below