A very believable and compelling reason to believe that in time we will find that life can be, even in our own planetary system. Here are seven reasons why scientists believe that life certainly exists somewhere and just waiting for meeting with us. Maybe it will not be green-skinned ladies in flying saucers, but it will still be aliens.
1. Extremophiles on Earth
A key question is, can exist and develop life in worlds radically different from Earth. It seems the answer is yes, if we think of the fact that even on this planet, there are extremophiles, or organisms that can survive in the extreme conditions of heat, cold, exposure to toxic (to us), chemicals, and even in a vacuum. We found the creatures that live without oxygen at the edge of the hot volcanic vents on the ocean floor. We found life in brackish waters in the mountains of the Andes, as well as in sub-glacial lakes in the Arctic. There are even tiny organisms called tardigrades, can survive in the vacuum of space. So, we have direct evidence that life can exist quite well in a hostile environment on Earth. In other words, we know that life can be stored under conditions that we have seen on other planets and their moons. We just have not found it.
2. Evidence of the starting materials and prototypes for life on other planets and satellites
Perhaps life on Earth originated from chemical reactions that eventually formed the cell membrane and the proto-DNA. But these primary chemical reactions could begin in the atmosphere and in the ocean with complex organic compounds, such as nucleic acids, proteins, carbohydrates and lipids. There is evidence that such “precursors of life” already exist on other worlds. There they are in Titan’s atmosphere, astronomers noticed them in a rich environment of the Orion Nebula. Again, this does not mean that we have found life. However, we found the ingredients that, in the opinion of many scientists contributed to the development of life on Earth. If these ingredients are common throughout the universe, it is quite possible that life originated in other places, not only on our own planet.
3. The rapidly increasing number of planets similar to Earth
Over the last decade, hunters celestial bodies discovered hundreds of planets outside the solar system, many of which, like Jupiter, are gas giants. However, new methods of finding planets and allowed them to find smaller, solid worlds such as Earth. Some of them even are in orbit around their stars in the so-called “habitable zone” that is, at a distance, when they arise temperatures close to the earth. And given the myriad of planets outside the solar system, it is likely that one of them there is some form of life.
4. The enormous variety and persistence of life on Earth
Life on earth evolved in extremely difficult conditions. Sometimes she managed to survive the most powerful volcanic eruptions, meteorite impacts, ice ages, droughts, ocean acidification and radical changes in the atmosphere. We also see the incredible diversity of life on our planet in a relatively short period of time – in geological terms. Life is also
fairly stable thing. Why would not blossom and take root on one of Saturn’s moons, or in another star system?
5. The mystery surrounding the origin of life on Earth
Although we have a theory about the origin of life on Earth, in which the figure I mentioned earlier complex carbon molecules in the end, it is a mystery how these chemicals are combined to form a fragile membrane, eventually become cells. And the more we learn about what a hostile environment existed on Earth when life originated and developed – full of methane atmosphere, boiling lava on the surface – the mysterious secret of the origin of life becomes. There is a general theory, which states that a simple single-celled life actually originated somewhere else, maybe on Mars, and brought her to Earth meteorites. This theory pansermii and it is based on the hypothesis that life on Earth came from living on other planets.
6. Oceans and lakes are common, at least in our solar system
Life on Earth began in the ocean, and it follows that the water she could appear in other worlds. There is strong evidence that water once flowed on Mars is free and abundant, and on Saturn’s moon Titan has methane seas and rivers flowing on the surface. It is thought that Jupiter’s moon Europa is one big ocean, warmed by the bark of the moon and completely covered with a thick protective layer of ice. In each of these worlds could be a life once, and maybe still exists.
7. Theory of evolution
People often use the Fermi paradox as evidence that we will never find intelligent life in our universe. On the other side stands the evolutionary theory, which postulates that life adapts to environmental conditions. Darwin and his contemporaries hardly thought about life on planets outside the solar system, when he created his theory of evolution, but they argued that the place where life can take root, it will do it. And if you think about it, that our environment is not only the world, but other star systems, and interstellar space, we can make the original assumption in the interpretation of the theory of evolution – that life and adapt to the open space, too. One day we can meet up with the creatures that have evolved ways unimaginable to us. Or, we will be able to someday become such beings.