When we talk about aliens this picture comes to our  mind a grey coloured human like species with a triangle head and bulky eyes, frankly i didn't like this guy , i mean aliens will not look like this, its a picture from a sci-fi movie. Then how would Aliens look like? Do Aliens exist?

Our universe is enormously big with trillions of galaxies and in a Galaxy there are about 100-400 billion stars and about 100 billion planets orbiting them And we find life only in one planet. Its so weird, But according to the laws of physics it is same everywhere,so it follows that laws of life should be universal. We dont know what triggered life on Earth. If earth has there is chance that somewhere in the universe another form of life exist it may be single celled microorganisms or intelligent than us

Many astronomers believe life exist in the universe other than Earth. An American astronomer and astrophysicist Frank Drake who is founding member of SETI (Search for extra terrestrial intelligence) Proposed an equation called drake equation. The Drake equation is a probabilistic argument used to  estimate the number of active communicative extraterrestrial civilization on the milky way galaxy.
The Drake equation
As an young science enthusiast i profoundly believe that intelligent life exist. But the question is that why they are not communicating with us. There are many theories regarding this, people believe that aliens are so intelligent and they are waiting for us to become a type 1 or type 2 civilization, or they dont really want to make contact with us, or they are not much developed us we are.

There many exoplanet (planet like earth) if a single planet has life there are many planets with life. If we can prove life in any planets other than Earth we can surely believe that  the universe is rich with life. There are many research taking place to find out traces of life in Mars, Titan,Europa. In future we will find it and unlock the mystery door of the universe.
Proxima Centauri b is the nearest Exoplanet which is orbiting the nearest star (4.25ly) Proxima Centauri

Reference: To know how Stars are born click here