The vehicles of life


In addition to the stars and planets, the Universe is populated by countless of small planetary bodies and tiny asteroids that act as vehicles of life in space and time.
They are often found far from suns and stars, drifting in the enormous cold and dark distances. 
The smallest, which are the vast majority, remain frozen by hundreds of millions of years without anything disturbing its long sidereal winter.
Others, the largest, have enough mass to generate some heat from their minerals and radioactive compounds.
In these celestial bodies the inner ice can melt forming luke warm  underground seas or lakes. 
These are probably the most common scenarios of the life in the cosmos.
Small bacteria and other hard-to-imagine organisms, survive, they 
reproduce and evolve in these environments, using the limited but lasting
available energy 
The Solar System contains millions, perhaps billions of these bodies. A large amount is far from the Sun, beyond the orbits of Uranus and Neptune. Some are closer to the center, in warmer regions, and occasionally  they get so close to the main star that their ice can vaporize and be ejected in the form of gas and dust.
These small bodies, which are often shown spectacularly in the night skies are called "comets." Some astronomers, increasingly, think that comets and their relatives the dark and cold distances are carriers of life forms whose characteristics
They are hard to imagine. Maybe some of them behave  themselves like true organisms with their "metabolism" and unique life history.
According to Chandra Wickramansinghe, Fred Hoyle and other researchers, life has been a common phenomenon in the Universe for a long time, almost since the beginning (if there were beginnings), spreading through the space embarked on the tiny comets.
Thus the first organisms in the remote origins probably arrived on Earth, several billion years ago. They continued to arrive since the, bringing new genetic contributions throughout the entire geological history of the planet.
Large and small icy blocks bombarded the atmosphere by enriching it with water and other light compounds and elements (nitrogen, methane, carbon dioxide, etc.).
That way, gradually, the original seas formed, the cracks in the crust were filled with water and the mixture of gases became ¡what we call "air" became.
To this atmosphere the gases emanating from the planetary interioralso contributed in a process of degasification that still continues. These gaseous emissions were mainly nitrogen and methane. Nitrogen is still present mostly in the atmosphere, and methane underwent oxidation processes enriching the surface of carbon dioxide and water.
From the book "Peoples, drugs and serpents", D. Antón, Piriguazú Ediciones