Until recently, scientists thought that the conditions supporting life in the Solar System were only on Earth. However, in light of the new information that has recently been discovered, it is possible that this may not be the case. Unlike the planets inhabited by aliens that revolve around distant stars, the traces of life in space (in its simplest form) may be in our cosmic neighbors.
If we talk to ten biologists and ask each one about the definition of life, we can get ten different answers. Life is a very difficult subject to be fully defined, but when you see it, you can understand it. Even the most open-minded biologists say there must be two conditions for life: carbon and liquid, for example water. The importance of carbon comes from the fact that it is best suited to produce complex, self-replicating molecules among all elements. These molecules are essential for life. Carbon is abundant in our galaxy. It emerges as a byproduct of the nuclear fusion that takes place inside the stars, and when the stars die, they spread to the galaxy, blending into the structure of the stars and planets that will be formed in the future.
We need water for a very basic reason. In order for complex chemical substances that perform their life functions to emerge, simple chemicals must meet and react with each other. That’s why they need to move around freely. This circulation occurs in a liquid in the most appropriate way.
The unique chemistry of water makes it the best solvent among all spontaneous liquids in nature. Luckily, water can be found in abundance, scattered all over the galaxy. So what does the existence of these two basic components tell us about the possibility of living elsewhere in our Solar System? Carbon is abundant in its satellites in the Solar System, but it is not possible to say the same for liquid water. The only planet Earth with plenty of liquid on its surface. This is because it has a very special position in the Solar System: it is neither too hot nor too cold. Therefore, the surface water does not evaporate and escape into space or freeze.
Until the beginning of the space age, most astronomers thought that liquid water could be found on the surface of our neighbors Venus and Mars. However, space probes destroyed this possibility. It turned out that Venus was a poisonous oven and Mars was a dull, deserted desert. In the light of recent information, it turned out that a celestial body does not necessarily have to be present in this particular region for life to exist. Astronomers have found evidence that liquid water can be present in different parts of the Solar System.
The icy satellites on the outside are heated by the tidal waves of the planets and there is the possibility of liquid water in them. In some satellites, even if the temperature is below zero, water may remain liquid due to chemicals such as salt and ammonia. Meanwhile, in recent years, biologists have found that life exists in the Earth even in alkaline, acidic, dark and cold environments. The discovery of these extremophile organisms supports the theories that there may be sprouting forms of life elsewhere in the world under the most extreme conditions.
Where to Start?
At first glance Mars seems the best candidate. The initial findings were not promising, but the probes we sent to orbit, the findings of the research tools we circulated, revealed that the Red Planet was more than a barren desert. The soil on the surface combines with ice to form permafrost, with glacier-like structures in some areas. Earth’s ancient forms of Mars once supported the argument that there was liquid water in Mars when the atmosphere was thicker and perhaps with a different trajectory. We are almost certain that Mars has the conditions to support life billions of years ago, but is there anything left? This is the most important question…
The last vehicles sent to Mars only to search for traces of life were Viking missions in the 1970s. These robots underwent chemical reactions of soil samples collected from the surface and tested for residues specific to living metabolisms. The British Beagle 2 survey vehicle had more detailed exploration possibilities, unfortunately it collapsed during the landing in 2003.