Given the size of the Universe, the chances that extraterrestrial life exists somewhere, there, and high. Some scientists even think that we will find her by 2040. But what it can be similar? A popular representation of aliens that is available to the people, tells us that they should be a short, gray humanoids with large heads, are generally not very different from humans in appearance. Below you will find ten reasons why alien species are unlikely to be similar to us.
Their planet has a different gravity
Gravity is a key factor determining the development of all organisms. In addition to the size limits of terrestrial animals, gravity also defines a number of very specific adaptations. The examples we see on Earth. The organisms that came out of the water onto land, gained limbs and complex skeletons, because the buoyancy of water no longer save them from gravity. And although the planet’s gravity must fall within a certain range (high enough to maintain an atmosphere, but low enough that all is not quite flatten out), this range is still quite broad and allows a variety of conditions for the existence of life.
Imagine a hypothetical situation: the force of gravity on the Earth has doubled. Although this does not necessarily make all complex life on earth to turn into cherepahoobraznoy, chunky creatures, two-legged people will have very tight. Even if we manage to keep our two-legged method of transportation, we will definitely become much lower and have larger bones, are able to cope with high gravity. The earth with half the force of gravity is likely to have the opposite effect. Land animals need less muscle and weaker skeletons to deal with gravity, and life in General will become taller and larger.
And although we may speculate about the peculiarities of life at high and low gravity, it is impossible to predict more subtle adaptation. And this adaptation could even more alter the appearance of another life.
Their planet has a different atmosphere
Like gravity, the atmosphere is another key factor that determines the development of life and its characteristics. Arthropods, for example, who lived during the Carboniferous period Earth 300 million years ago, were significantly greater due to the higher oxygen content of up to 35% compared to today’s 21%. Among species from this time period have giant dragonfly meganeura with a wingspan of 75 centimeters, a giant Scorpion Pulmonoscorpius 70 centimeters in length, and scary millipede Arthropleura, which could grow to 2.5 meters. If 14-percentage difference difference in oxygen content may affect the size of the arthropods that will be on a planet with atmosphere, the oxygen content of which will be much lower or higher?
And we’re not even indirectly mentioned the possibility of the development of life, which do not need oxygen — it’s an infinite number of possible atmospheric compositions, which can be work. Researchers have found a multicellular organism that does not need oxygen on the Ground, so the chances that it will thrive on a planet with a different atmosphere, too, should not be discarded. Aliens that evolve on such a planet, will surely differ from us.
They depend on another item
Almost all life on Earth has three biochemical requirements: it is carbon-based, she needs water and she has DNA to pass genetic information to their offspring. But it would be too “earthly” to put that life everywhere in the Universe follows the same rules, when it can be based on completely different principles. Let’s look at the first requirement — a carbon.
On Earth all living organisms consist of a large number of carbon. There are several reasons: the fine carbon associated with other atoms, relatively stable, available in large quantities and can form complex biological molecules necessary for organisms.
And yet, it may well be that other elements will take its place as the most popular alternative is the silicon. Carl Sagan invented the term “carbon chauvinism” that describes our bias that the carbon should be the basis for life everywhere. If it does exist, life based on silicon would be completely different from that of the earth. For example, silicon requires higher temperatures to achieve high reaction condition.
They do not need water
As mentioned above, water is another universal requirement for all life on Earth. Water is essential, as there is in liquid form in a wide range of temperatures, is an effective solvent acts as a transport mechanism and provides the chemical reactions. But this does not mean that other liquids are unable to take their place in the Universe. The most popular replacement for water as the basis for life is liquid ammonia, as it possesses many of the qualities of water, for example, high specific heat (amount of heat required to raise its temperature).
Another popular alternative is liquid methane. A number of scientific papers that use the data of the spacecraft NASA Cassini that suggests that life based on methane could exist in our own Solar system on Saturn’s moon Titan. Apart from the fact that ammonia and methane are quite different from the water composition, in liquid form, they also exist at much lower temperatures. It is easy to guess that a life based on these substances as a universal solvent, it will look different.
They have an alternative form of DNA
The third key element of the riddle of life on Earth — a way to store genetic information. For a long time we believed that only DNA can do that. But it turned out that can be an alternative. Not so long ago, scientists created an artificial alternative to DNA — KNK (ksenodoxeiou acid). Like DNA, KNK can store and transmit genetic information and evolve.
In addition to having alternative forms of DNA, alien life could also produce and use other proteins. All life on Earth uses a combination of just 22 amino acids for protein production, but in nature there are hundreds of amino acids, not to mention those that we can create in the laboratory. Extraterrestrial life not only could have their own version of DNA, but also other amino acids for the production of other beys. Such fundamental differences at the molecular level can lead to the fact that life will not resemble anything on our planet.
They have evolved in a different environment
If the planetary environment can be constant and homogeneous, it also can vary greatly depending on the planet’s surface. This, in turn, can lead to a number of very different habitat conditions with specific characteristics. Such variations could exert pressure on species and lead to the fact that life will develop absolutely differently. Here on Earth there are five such divisions of tundra, grassland, desert, water and forest biomes. Each of them is home to organisms that have adapted to their environment and are very different from organisms in other biomes.
Creatures from the depths of the ocean, for example, have several adaptations that allow them to survive in cold, dark environment with high pressure, along with the overall fitness of the body in the water. These organisms not only similar to humans but are unable to survive in our earthly environment.
In this sense, alien life is not only radically different from earth’s because of the General planetary characteristics, but also because of the ecological diversity of the planet. Even here on Earth, some of the most intelligent organisms — dolphins and octopuses — don’t live in the same habitat as us.
They are older than us
Given that the stereotypical alien race more technologically advanced than we are, it’s safe to say that they existed much longer than humanity. Even more likely is that the life does not develop overnight and at the same pace throughout the Universe. Even a difference of 100,000 years is nothing compared to billions of years.
This means that extraterrestrial civilizations not only had more time to develop, but also on artificial evolution — the process which used the technology to redesign their bodies as they like, instead of having to wait for evolution will do its work naturally. They could, for example, to adapt itself to space exploration, to extend the life of to infinity and get rid of the biological constraints — the need to breathe and eat. Such bioengineering definitely would have led to an unusual body shape and, perhaps, the complete replacement of body parts with artificial parts.
If it seems strange, do not forget that we ourselves are moving in this direction. “Designer babies”, high quality dentures, pacemakers and other implants can make us the true cyborgs.
They are living on a wandering planet
The sun is essential to life on Earth. Without it, plants could not perform photosynthesis, and without it would collapse the entire food chain. A large part of life would become extinct in a matter of weeks. And that’s not to mention the fact that without the heat of the Sun the Earth would be covered with ice.
Fortunately, the Sun is not going away and not going anywhere soon. But only one in the milky Way galaxy has about 200 billion of “wandering planets” planets-derelicts. These planets have no stars and rotate by themselves in the darkness of space.
Could the planets be life? Scientists believe that under certain conditions, Yes. It all depends on the source of energy. The most probable alternative for the vivifying warmth of a star is a planet with an internal engine. On Earth internal heat is responsible for plate tectonics and volcanic activity. And although this will be insufficient for the development of complex life, we should not overlook other factors from accounts.
A planetary scientist David Stephenson proposed the following mechanism: wandering the planet with very dense atmosphere that can retain heat for an indefinite period of time, providing the existence of liquid water. On the planet this kind of life could evolve to a very serious level, like our life in the ocean, and even go on the land.
They can be non-biological
Another possibility that is worth considering: aliens exist in a completely different form. They may be robots created to replace their biological bodies with artificial parts or created by other types. Seth Shostak, Director and senior astronomer of the SETI Institute is generally believed that such artificial life is inevitable, and our biological forms, these sacks of meat, is just a transitional phase.
We are on the verge of development of artificial intelligence and advanced robotics; who said that the human race will not move in a timeless and durable robot body? This transition, however, can be enforced. Prominent scientists such as Stephen Hawking and Elon Musk, have warned that AI could just rise up and take our place.
And we only scratched the surface in thinking about robots. What about energy beings? This is interesting from a practical point of view. This form of life would not have any restrictions of physical body and would be a theoretical improvement of the above-mentioned robotic life. The energy you create will definitely not be similar to people because it will not have a physical form and will not say.
The accident
Even after counting all of the factors listed above, don’t underestimate the power of randomness. As far as we know, there is no guarantee that all highly intelligent life must have a humanoid body shape. What if the dinosaurs never became extinct? They would be able to develop an intelligence like ours? What if a completely different animal evolved into intelligent life form on Earth instead of us?
In fairness, it should restrict the selection of possible candidates, the most developed groups of animals — birds and mammals. But among these two groups there are plenty of possible species that could develop intelligence comparable to a human. Dolphins and crows are quite clever and could become the masters of the Earth. Summing up, it should be said that life is an infinite number of ways, so the chances that intelligent beings similar to us, appears in this Universe the second time are astronomically low.
10 reasons why aliens are unlikely to be similar to us
Ilya Hel