There are several theories that have a right to exist.
Extremophiles on Earth
Extremophiles - are living organisms capable of surviving
in a completely intolerable in human terms conditions:
Extreme heat, cold or toxic chemicals, and even in a vacuum.
We found creatures living in volcanic vents,
in the salty waters of the Andes, covered with ice in the Arctic.
Tiny creatures called tardigrades are able to survive in the vacuum of space.
In other words, we know that life can exist in such conditions,
we sometimes found on other planets and moons.
We just have not found it yet.
The presence of chemical precursors of life on other planets
Precursor - a substance involved in the reaction leading to the formation of a target substance.
Apparently, the origin of life on Earth was the result of a number of
chemical reactions that form complex organic compounds
- Nucleic acids, proteins, carbohydrates, lipids - in the atmosphere and the ocean.
There is evidence that these "precursors of life»
found on other planets. For example, in the atmosphere of Titan and the Orion Nebula have found precursors.
Although we do not find life, we found it "ingredients».
The rapid growth in the number of Earth-like planets
The rate of detection of planets similar to our own, everything accelerated over the past 10 years, scientists have found hundreds of extrasolar planets,
Many of them - gas giants like Jupiter.
But new technologies make it possible to search for planetary detection of small rocky worlds,
like Earth. Some of them even revolve around its own unique sun.
Considering how much we find such planets, it is likely,
that the next will be some form of life.
The variety and persistence of species living on Earth
The Earth is not just passed through the various times of crisis:
megavulkanov eruptions, meteorite attack, glacial periods, droughts,
radical changes in the atmosphere, and so on. n. However, the life on it
It continues to this day. It can be said that life - quite tenacious.
Given this persistence, as well as an incredible variety
living organisms on the Earth, it is possible, again, to conclude
- Somewhere in the universe there must be something like that. Why
not on one of Saturn's moons, for example? ..
The mystery surrounding the origin of life on Earth
We have different theories about how our planet life originated,
but we still do not know anything for sure.
It is still unclear what gave rise to chemical compounds,
that they collectively form a living cell.
Especially considering that quite a hostile environment on Earth
millions of years ago, in which it occurs:
in the atmosphere was full of methane, and the planet's surface was covered with boiling lava.
One common theory is,
that life originated not in the world, and the world more suitable
for this condition, for example, on Mars, and then was brought
Earth on meteorites. This theory is called the theory of panspermia.
If it is true, then why not extend the life somewhere else,
other than Earth?