May be one of the observers of what is happening in the world of the search for life in the universe , but that were not well let me enumerate you some different ways in which the scientists looking for life, so before you start answer the question posed in the title.
There is no doubt that the research methods in this matter very numerous , there are observatories used by the Foundation " SEI ATI " "SETI" to pick up signals coming from space that could be intelligent civilizations . There are also looking for microbes on Mars , duration spacecraft that were sent to search for life there are multiple , and the last one was sent to Mars is a composite " Curaossite " They now roam on the surface of the Red Planet in search of any evidence for the existence of life .
In addition there is also a search using the telescope Kepler - accompanied by several telescopes other - for Earth-like planets , then the telescope revealed more than a thousand planet in the totals asterisk , indicated by the presence of more than sixty billion a planet similar to Earth - statistically - in our galaxy only .
This research in its infancy , but scientists did not find yet any radio signal sent from the planet has intelligent civilization , or any evidence of microbial life on any planet , not even the discovery of a planet and one identical to the ground completely .
And now we wonder , what makes scientists believe that there is life outside Earth , even though they did not find any evidence of its existence until now? Is the search for life based on a hunch or a guess ? The search for them or due to scientific reason and logical makes scientists expect its presence in the universe ? This enthusiasm that caused them to divert billions of money in order to get the answer depends Allam ?
Of course, the scientists were not to look for life is that the scientific evidence does not indicate it, but do not reveal science facts of life on Earth , scientists would not have dared to put forward such a hypothesis : the hypothesis of the existence of extraterrestrial life .
I think a lot of people in ancient times that the Earth is the center of the universe , and that the heavenly bodies revolve around, but " Galileo Galilei ," the heart of those scales and disarm the Earth from its position , to make it a crime just like any other nearby celestial bodies that revolve around the sun . It is the loss of a central earth moved scientists and philosophers to believe the existence of other planets may contain life .
With the passage of time and the discovery of the solar system in ways that accurately moved exploration to search for Earth-like planets in the Milky Way , exploded the number of planets suddenly , and after that the sky was full of stars only , has become the number of planets as a whole equal to the number of stars, which are thought to prepare as much as 300 billion stars in our galaxy .
The biological life , it has turned its centrality upside down after he revealed Darwin's secrets , and after more than 150 years on the theory of evolution , which show how the evolving organisms by natural selection is no longer for the animals any centralized in the universe , but the natural biological processes are the basis of all diversity The differences we see today .
And when they take an inside look at the world of life to find out the details , we find that life is made up of chemical compositions and molecules , " said de any " complex , and all of these compositions consist of atoms , and these atoms but are present in the earth , and the earth come from exploding stars , respectively .
And how beautiful what the cosmologist and physicist " Lawrence Krwas " to describe this relationship : but your right hand consisted of atoms blown explosion of a star and your left hand consisted of atoms exploding star last . Each of these complex structures , but it is rooted to the stars , there was the approximately 300 billion stars in the Milky Way , is it possible to be a dim blue Earth in the vast universe is stable only for life ?
As for the origin of starting life for he returns to water , water is the focal point and essential in the formation of primitive organisms on Earth , and then evolved into different forms after that , until the water is no longer the Earth is the center custodial him alone , scientists have discovered meteorites and asteroids , which contain huge amounts thereof , may be responsible for pollination hemisphere ample quantities of water to form oceans as a whole, but there a belt full of enormous asteroids that it saturated .
A few days ago , scientists discovered that the asteroid Ceres "Ceres" contains a quantity of water equivalent to those that cover the entire globe sailor , despite the fact that the asteroid diameter smaller than the diameter of the Earth six times .
Now step back and ask , why not have a life outside of Earth ? Why not? Every sign indicates that the raw materials that make up the objects in the earth exist in all parts of the universe , and the components of these exist in abundance there , and kitchens career in the universe is working day and night in the manufacture of that life , including what works , including what fails , some of which is very hot , some of which is very cool , both of which are not allowed to life ( as life on earth ) to emerge , but some may be able to , it's those planets moderation , and it would be no life , perhaps with differences in forms and manifestations .
Therefore scientists looking for life , this is not an arbitrary or random search , but that he had discussed based on sound science and logic , and when the day comes where scientists discover extraterrestrial life would be a surprising day today , despite all expectations to its existence there .
