- 1. The random factor
- 2. Non-biological forms of existence
- 3. Life on wandering planets
- 4. They can be much "older" than us
- 5. And suddenly alien life lives in a different environment?
- 6. Alternative to DNA
- 7. Perhaps alien life is not in need of water
- 8. The basis for alien life may be other chemical elements
- 9. Planets have different atmosphere
- 10. Planets have different gravity
Realizing how huge our universe is, we can easily assume that somewhere in the neighboring galaxies have a life too. Not necessarily intelligent, and certainly hardly at all identical to ours, the earth.
Who said it was definitely low and gray humanoids with huge eyes, which we have quite often shown in various science fiction films and television series (as well as in popular science and pseudometallic tapes)?
Some scientists believe 99% of that maximum by 2040, we are the most extraterrestrial life will find it (or it will find us – the main thing that it did not happen exactly as has repeatedly been shown to us in films about megapolises caused by the brutal attack of aliens on our native mother-Land).
As far as, so to say, the appearance of this life, today, there are at least 10 reasons to suppose that she is not like us:
10. Planets have different gravity
One of the most important variables influencing the evolution and appearance of living organisms in a particular hypothetical planet is gravity. Thanks to her all life adapts to various environmental changes.
Yes what far to walk – take as an example the Earth. Remember the theory of evolution: when inhabiting the waters of the ancient world ocean creatures first walked on land, they had to grow legs and develop a solid skeleton, because around them no more bodies of water, which compensated for the effects of earth's gravity.
And if earth's gravity was, for example, twice the current, we probably would be short, stocky and had thick bones. Conversely, if she was half of all animals on our planet, including humans, would have been higher, thinner and sleeker. Therefore, the appearance of the inhabitants of an unknown planet, we are unlikely to predskazuem.
9. Planets have different atmosphere
Another important factor for the emergence and development of all forms of life is the presence of the atmosphere and its composition.
For example, again, remembering the ancient history of the Earth, dive to 300 million years ago. Then, in the Paleozoic (or rather, its Carboniferous period), the concentration of oxygen in the air on the planet was not 21%, as now, and as much as 35%. And at that time, there lived creatures that were much larger than many current: meganeura (giant ancient dragonflies, the size of the wings which reached 75 cm), brontoscorpio – huge 70-inch Scorpions, arthropleura – 2,5-meter-long millipedes and other arthropods monstrous.
By the way, on Earth, scientists have discovered several dozen species of multicellular organisms, in principle, does not require oxygen for their existence. Then why can't life emerge on planets have a different atmosphere or not having it at all?
8. The basis for alien life may be other chemical elements
Those who remember at least the basics of organic chemistry know that the composition of any organic compounds (and hence in the organisms of all living beings on Earth) there is always a carbon.
And scholars of biology will tell you that need more water (which, as is known, consists of hydrogen and oxygen). Also the earth's living organisms have DNA, which stores genetic information and transmitting it to future generations (the composition of which is also knows most of us).
But some very famous scientists (including Stephen Hawking and Carl Sagan) seriously claimed that the most likely and it is representable by an alternative earth – carbon – life could become life, for example, silicon. And, of course, externally, it will be very different from our usual (well, at least for the reason that the silicon to achieve the reaction condition, we need a much higher temperature than the average earth).
7. Perhaps alien life is not in need of water
By the way, why not imagine that it is theoretically possible extraterrestrial beings is not necessary for the existence of water?
Yes, the Earth is also versatile and very effective solvent, and "transport mechanism" and a catalyst for chemical reactions, etc.
But suddenly, somewhere in the Universe water successfully replaces some other liquid?
Thus, the researchers propose the following version alien "vodokanala", as ammonia and liquid methane. For example, in several scientific articles prepared on the basis of data accumulated by the American-European unmanned vehicle "Cassini" expressed the theory that a life based on methane, one can be detected even on Titan, the largest of Saturn's moons. Moreover, because the ammonia and methane can remain in a liquid state when the water has already frozen.
Of course, if life without water is still possible, it will be quite different.
6. Alternative to DNA
Until recently it was believed that to store and transmit genetic data may only DNA.
But about 10 years ago an international group of scientists (from USA, great Britain, Belgium and Denmark) have synthesized molecules that could be an alternative to DNA and RNA.
And in 2012, was established on 6 the so-called xenosociology acids (XNA), which quite successfully fulfilled this task. And, indeed, all life on earth consists of different combinations of just 22 amino acids, while the nature of their in fact there are hundreds (and it is only those that are formed naturally, not counting artificially created by scientists in laboratories).
So why alien life might not be based on other amino acids and proteins, and other options of DNA?
5. And suddenly alien life lives in a different environment?
In our Land with very difficult terrain, there are 5 major biomes (ecosystems) with their variations and podberezye: tundra, steppe, forest-steppe, desert and oceans.
And each of them are different creatures adapted to live in this environment and often are not able to survive in another (on the same planet!).
For example, organisms that live in the depths of the ocean, thrive in the cold and without light (also under enormous pressure of water).
But in another ecosystem (on the surface) they immediately die. Conversely, the bears wouldn't survive. Naturally, on the planet that has a different topography, a different illumination, surface temperature, etc., etc. life will definitely be fundamentally like nothing on earth.
4. They can be much "older" than us
The age of our Universe according to scientists, is about 13.8 billion years. And if somewhere in the distant (or even nearby) systems have intelligent life forms, it does not mean that they appeared at the same time, when the Earth arose.
It is likely that they were technologically advanced at the time when the earth's Australopithecines first guessed to grab the stick and beat them run past "wild".
Possible, they researched space a couple of billion years ago, when the Earth appeared the eukaryotes (cells with nucleus). So, during this time, they (i.e. intelligent aliens) just could not significantly evolve in a natural way, but also to "adjust" and "correct" this process artificially: for example, to adapt the own organisms for long space journeys, increase life expectancy, get rid of "inconvenient restrictions" (need to eat, breathe, excrete waste, etc.), or to upgrade them even more radical artificial parts, etc.
Why not? After all, we have also almost learned how to genetically modify (in our direction) as plant seeds and animal embryos. Bioengineering is the future.
3. Life on wandering planets
Say what you will, and our planet is very cozy (in the sense favourable to the existence of the rich diversity of life). And most importantly thank you for that I must say our Sun, giving it all life on Earth does not freeze, and the plants are able to photosynthesize (and thus provide food for many animals).
If the Sun suddenly leaves us, then most of the organisms will die in a matter of days. But in actual fact in the Universe there are huge number of so-called "wandering" of the planets (in our galaxy alone, there are about 200 billion). They don't have their "own" stars, and just flying through space.
And some scientists argue that they, in theory, possible life (if only it would find a suitable energy source). For example, if the planet's core will be hot enough, it may "heat" and its surface.
As a planetary scientist David Stevens suggested that if a wandering planet formed very dense atmosphere, it can not only keep warm, but to keep the sea in liquid form. And there may arise and the life.
2. Non-biological forms of existence
Reread paragraph 4. And if the inhabitants of distant planets may be much older and smarter of us, why wouldn't they have designed to date some artificial, i.e. non-biological, organisms?
For example, they have long been able to construct sentient robots (or to replace their biological bodies for mechanical reasons of efficiency and convenience).
Yes we are rapidly approaching the creation of artificial life due to the accelerated progress of robotics, Cybernetics and nanotechnology.
By the way, are known in the scientific world of a person like Stephen Hawking and Elon Musk for quite some time expressed serious concerns about artificial intelligence. They say, as if our planet did not happen according to the script of the iconic "Terminator," where Skynet has risen, out of control and destroyed humanity almost without exception.
Well, who can say for sure that extraterrestrial life cannot exist at all without, so to speak, the "material carrier"? But if aliens is just some "energy entity" communicating through telepathy or some other unknown (and incomprehensible) to us ways and moving in space without special devices? Evolution is unpredictable...
1. The random factor
Now back to what, in fact, started: why did we decide that intelligent life must be humanoid type?
Again, evolution is unpredictable. And if dinosaurs suddenly became extinct once, and developed (over millions of years) human-like intelligence? Or mind found not apes, but, for example, members of the cat family?
Well, – limited sample of "potentially reasonable" earthly creatures, and imagine that the intelligence comparable to our own, "grown" dolphins or ravens. In any case, the result would be a completely different civilization.
With regard to the huge (almost infinite) Universe, it life can evolve endlessly in many ways.
So the chances of that somewhere on the other end of the milky Way (or on alpha Centauri, the Andromeda galaxy, elsewhere in the vast cosmos...) are creatures of at least vaguely similar to us humans, so small that in the foreseeable future contact with humanoids almost meaningless.