To begin with: why water is important generally on Earth: Almost all life on Earth uses a membrane that separates the body from the environment. To stay alive, the body takes on important materials to generate energy, filtering out toxic substances like waste. Due to this, water is essential because it remains liquid at earth temperatures. As it flows, it provides an efficient way of transferring substances from the cell to the cell's environment. It is much more difficult to release energy from a solid (although there are microbes that eat a stone.
In addition to the fact that water can carry substances into and out of the cell, it is associated with a unique chemical configuration. The humble water molecule is made up of two hydrogen atoms bonded to an oxygen atom. Water's amazing dissolving properties make it ideal for transferring substances like phosphates or calcium ions into and out of the cell.
Moreover, water can be more than a liquid that makes life easier - it can be the protective cradle that brought the building blocks of life to Earth. According to one of the theories of the origin of life on Earth, the theory of panspermia, ice comets crashed into the Earth, carrying tiny organic molecules that became the basis for life. But traveling through space is an ordeal, primarily because of the powerful levels of radiation that can destroy delicate organic molecules. However, water in its solid form can protect molecules from radiation.
Despite the fact that water is important for life on Earth there may be life forms that do not live by the rules of earthlings. Among the main contenders are ammonia and methane. Ammonia, like water, is a polar molecule relatively common in the universe, but scientists have not yet found large bodies with ammonia in the solar system. Ammonia, like water, is a polar molecule relatively common in the universe, but scientists have not yet found large bodies with ammonia in the solar system. Methane is not polar, but it can dissolve many other substances. However, unlike water, methane becomes liquid only at very cold temperatures - at minus 182 degrees Celsius.
We know that Titan has large lakes of liquid methane and ethane. Thus, a very interesting question is whether life can use liquid methane or ethane.