Scientists at the Massachusetts Institute of Technology have looked at alternative solvents to water that could be suitable as a basis for the existence of life on other planets. According to the results of the study, “published” on the arXiv preprint server, only water turned out to be the only suitable basis for life.
The researchers looked at whether there were other molecules common in the universe that could play the same role as water, dissolving essential nutrients, making them available to living organisms. Such substances must meet four criteria: dissolve only some molecules (but not all), play an important role in metabolism, do not destroy a wide range of complex organic molecules, and exist for billions of years on rocky planets.
It turned out that of all known solvents, water is the only substance that satisfies these conditions. Ammonia satisfies the first three conditions, but it is easily destroyed by ultraviolet radiation. Also, where ammonia exists, water also exists, so it will not be the primary solvent.
Concentrated sulfuric acid also satisfies the three basic conditions, although it is unknown whether it can support a diverse set of organic molecules. As for another common potential solvent, carbon dioxide, scientists question whether its properties are suitable for supporting complex metabolism. However, it reacts with many types of molecules, and scientists suggest that the properties of liquid CO2 merit further study.