All life forms we know are composed of carbon, nitrogen, oxygen and hydrogen. But even if we accept that life on Earth and in our solar system is extremely organic, does that mean that life is like that in the entire universe? More than one generation of scientists and theorists have been arguing on this topic. However, most of them believe that life can take the most unexpected forms.
Little green men
Nowadays, it is difficult to find a person who has never seen any series of X-files. Of course, we have no doubt that there are. However, the cult series of the 1990s cemented the image of young green men in the mass cultural consciousness and made them an integral part of any conversation about life outside the Earth.
In the meantime, scientists are graciously smiling at the mention of little green men. Life on Earth and therefore all life we know in the universe have several basic characteristics. Most of the compounds we can find contain carbon. Scientists call these compounds organic.
But this does not mean that organic life is the only one in the universe. In fact, we can easily imagine the diverse conditions under which there will be unusual life forms for us. If you've watched at least a few episodes of Rick and Morty, you know what our imagination is capable of. But let us still listen to the scientists.
Life based on ammonia
Most of the chemical reactions underlying life are in water. Water dissolves many different molecules. A good solvent is what you need for complex chemical processes that lead to life as such.
Physics of Extraterrestrial Life: Extraterrestrials must be Earthly
Strange as it may seem, ammonia is quite common in the galaxy. It is also capable of dissolving organic compounds such as water, but unlike the latter it dissolves some metal compounds. This opens up the possibility of using more interesting chemicals in living organisms.
Ammonia-based life may exist outside the so-called zone of Zlatilox (the extent to which liquid water and optimum temperatures can exist on the planet). Astrobiologists often refer to Saturn's moon Titan. The fact is that it can hold both oceans of water and ammonia under its water.
So you can safely try to imagine something like an ammunition octopus or intelligent ammonia fish, for example. We do not even know that you are probably better than us to handle this task. If possible, write about it in our Telegram chat – we'll discuss.
Silicon is an excellent ingredient for living somewhere in the universe. Carbon is able to form bonds with four atoms simultaneously, to bind to oxygen, forming polymer chains, making it an ideal component for the complex chemistry of life.
However, silicon is rather restricted as the basis of life. Silicon forms stable bonds with a limited number of chemical elements. The very chemical processes of silicon are unstable in an aqueous environment.
However, under certain conditions, silicon-based chemistry can be life-supportive. Such life forms can exist in an environment rich in methane and even liquid nitrogen, and such places exist in the universe. So why not?
And what do aliens look like to you?