"There is no such thing as Alien"

This is not my ideology. These words were said by my 7 year old brother this evening while having tea ... though he doesnt have any formal knowledge about aliens but this is something he has learnt from the cartoons and "encyclopedia" he read at his school.
I however felt inspired to think deeper into it.

Earth is the only planet in the solar system that has water in its liquid state and the right temperature for life to exist. We are not close enough to be fried yet we are not too far away that we freeze.We are just at the right place from the sun to experience life. So this sort of erases out the possibility of life in universe.

But to look in a broader picture, UNIVERSE is not just planet Earth, its neighbors Mars and Venus, Sun , other planets, their moons or even Alpha centauri. Universe is a collection of millions, billions and zillions of such planets and solar systems.

The above picture shows our dot-like solar system in the view of Milky Way. And Universe is a collection of billions of galaxies like Milky way which in turn have zillions of "dot-like" solar system.
So, ignoring the very possibility of existence of extra terrestrial life just because they are not in our knowledge doesnt seem fair enough.

An extraterrestrial is defined to be life that did not originate on Earth and that can range from microorganisms like bacteria to human beings.

In the past three-four years, biologists have found life forms in the most extreme places in the most bizarre conditions.In 1996, NASA found structures resembling nanobacteria in a meteorite ALH84001, that was thought to be formed of rock made from Mars (shown here)(source: wikipedia ).

Lachezar Filipov, deputy director of the Space Research Institute of the Bulgarian Academy of Sciences claims that aliens are currently answering 30 questions posed to them.He said the centre's researchers were analysing 150 crop circles from around the world, which they believe answer the questions. He said humans were not going to be able to establish contact with the extraterrestrials through radio waves but through the power of thought.

(crop circle in England and Switzerland: Wikipedia)

AND this...

Dr Edgar Mitchell, 6th man to walk on Moon, person holding the record for the longest ever moon walk- 9 hour and 17 minutes declared it officially that aliens exist and we have been visited by them.
He also says that we are in contact with them. He says the public still doesnt know the real story and only knows whatever the government is trying to project. His Kerrang! radio interview:
 
http://www.youtube.com/watch?v=RhNdxdveK7c


To sum up I would just say that believing a blind fact of existence of life only on Earth in such a huge Universe seems hard for me.