Since then, as the first people sent their views to the sky, to the planets, stars and galaxies beyond our home world, our imagination filled in the opportunity to find extraterrestrial life. However, when we approach this issue from a scientific point of view, we still do not have the first compelling evidence of life beyond Earth. Complex, diverse life forms we see on Earth are the result of more than four billion years of evolution, but in space, the ingredients for life there are often. We began to find organic molecules elsewhere in our Solar system, in interstellar space and even other stars. How much time will pass before we receive confirmation of the existence of something that is living beyond Earth? Today we are searching using four main methods. Some of them justify themselves first — no one knows.
To have life you need the fundamental ingredients necessary for life processes: raw materials from the periodic table. You need to have lived and died several generations of stars, pregnansy its nuclear fuel. We found stars with solid planets near by that seven billion years older than Earth, and have all the necessary elements. We found earth-like planets in potentially habitable zones of other stars across the galaxy. We found organic molecules, from sugars and amino acids to ethylformate that gives raspberries its scent, everywhere, from asteroids and young stars to protoplanetary disks and molecular gas clouds.
In General, we believe that in our galaxy the milky Way has over a trillion (1012) planets, and therefore the chances of life. But between the planets with the ingredients and authentic, high-quality alien life there is a huge difference. We don’t know whether there are in the Universe some other examples of life other than those that we saw on the Ground. Although scientists strongly suspect that if across the Universe will be the same ingredients and identical laws of nature, the uniqueness of life on Earth is extremely unlikely, we have no right to make such a conclusion unreasonable. In fact, we don’t even know the answer to the question: as we moved the inanimate to the living?
Our existence proves it’s possible. We can assume that if life POPs up anywhere in the Universe, it can achieve three different levels:
- Life begins on the planet but cannot exist, thrive or to change
- Life thrives, kept and stored for billions of years, introducing significant changes in the surface properties of the world that lives
- Life becomes intelligent, technologically advanced and or trying to communicate with the cosmos or conquer it, or both
Obviously, the more advanced the more we delight and excite the mind, but they are less likely. However, sometimes the rare items are the easiest to find because they stand out against everything else. Here are a few different methods that we can use to search for diverse forms of life. Three chances for mankind to find life beyond Earth.
Search in the Solar system
Although life thrives on Earth for billions of years, other worlds seem devoid of such splendor. If they have a life, she’s probably stuck in a primitive state. Mars and Venus had a wet, warm past, like the Earth, but today Mars is cold and arid, and Venus, a poisonous and hot. Meteorites that fall to Earth contain not only amino acids necessary for life processes, but many other elements that are not associated with biological processes on Earth. The moon like Europe and Enceladus have subsurface oceans of liquid water, which can be hydrothermal vents. At the bottom of the oceans of the Earth they are usually associated with life.
Although we have not found evidence of the existence of living beings, past or present, on another world, the possibility of such indescribable care. Mars has sedimentary rocks formed by water in the past; if we find fossils, when we dare to dig? On Europa and Enceladus may be the entire oceans are open to study; if we find microbes or something better in their waters? There is even speculation that diatoms are examples of primitive forms of life which find in the fragments of meteorites might have extraterrestrial origins. It is the least developed form of life that we can imagine, but we also have many worlds that we can physically get to, visit to measure. If a primitive, simple life will be everywhere, a careful study of our Solar system will reveal it to us.
Search for other extrasolar planets
Over the last 25 years the region ekzoplanetoy Sciences gave scientists a treasure trove of precious discoveries of thousands of planets orbiting other stars. Many of these worlds are small, solid and are just the right distance from their stars that allows us to assume that they have atmospheres and liquid water on the surface. We will not be able to find some microbes or fossils to them directly because they are outside the Solar system, but there are indirect methods that we could use to search for life, which managed to survive and thrive: finding changes that enliven the atmosphere of your planet.
Earth the only known planet with the ratio of molecular oxygen: 21% of our atmosphere is O2. Why did it happen? Life had billions of years to nourish the atmosphere with your biological waste. We think that oxygen is necessary for life, but in fact are animals evolved to use this ingredient to find him. With the improvement of our technology, we can measure molecular signatures ekzoplanetoy atmospheres, and perhaps even directly visualize exoplanets in search of clouds, oceans, and continental herbs. We have every reason to believe that a stable life on another planet, if we are properly to look for her, must seem to us in this century.
The search for signals from intelligent aliens
Here on Earth, we had single celled life billions of years, and then evolved multicellular organisms. It took 500 million years since the Cambrian explosion, to a complex, multicellular, well differentiated life became intelligent, technologically advanced civilization. People have already started to send signals to the stars and has already reached the moment when these signals were to reach the nearest stars. The search for extraterrestrial life in an attempt to contact her is a risky, yet effective method of searching for aliens.
In the 1960s we assumed that aliens would try to communicate using radio waves. 50 years have passed, and we’re not so sure. What are the alien types of signals may exist in nature? How do we decipher them? How will they send or receive interstellar signals? Will they conquer the space? If I can overcome the huge distances? All things are possible. If the signal — or, even better, the spacecraft will arrive on Earth, our view of the Universe completely changed, and our place in this Universe.
Although at the moment this is just a hypothesis, scientists suggest that life in the Universe is likely common, and the ingredients, and the possibilities for its occurrence are found practically everywhere. Life that thrives and supports itself on the planet, and also changes in atmospheric composition, would be less likely. Complex multicellular life would be even more rare. And the birth of the technologically advanced, intelligent civilization would be so incredible a phenomenon that a second chance she will not. However, whatever chances, we will continue to look. The options we have. No matter which method fires first, the opening day of another life it will be the greatest day in the history of life on Earth.