About 13.8 billion years ago, there was nothing..and then, bang! The universe was created. When the universe was only 200 million years old, it gave birth to stars. Slowly stars became very common in the universe. After many many years, our star, the head of our solar system, the Sun was born. The solar system was a violent place then. The mass emitted by the sun created small rocky bodies, one of which was the Earth. The Earth is a little over 4.5 billion years old, with its oldest materials being 4.3 billion-year-old zircon crystals. To date, we have no evidence as to how life came into being. Theories say that bacteria were brought to the earth by an asteroid, some say that it was aliens who ruled the planet and left it after mass destruction, whereas some theories say that there was a chemical reaction between water and organic elements (which created amino acids) on being hit by lightning.

Unicellular cells developed to form complex organisms like us which had the ability to think and reason. As there was a development in education and space sciences, one major thought kept hitting everyone’s mind – “Are we alone?”. The Universe is a huge place. It is a waste of space if we’re the only ones living in it. Come on.. there have to be aliens right?

There are about 100,000,000,000 galaxies in the known universe. Each galaxy has 100,000,000,000 to 1,000,000,000,000 stars. Planets also appear to be common in every solar system observed so far. The milky way itself has 400 billion stars i.e. 10,000 stars for every single grain of sand on earth! Then why have we not been contacted by aliens till now?

Drake’s Equation and Fermi Paradox

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The Drake Equation is:
N = R * f_p * n_e * f_l * f_i * f_c * L

where:
N = The number of broadcasting civilizations.
R = Average rate of formation of suitable stars (stars/year) in the Milky Way galaxy
f_p = Fraction of stars that form planets
n_e = Average number of habitable planets per star
f_l = Fraction of habitable planets (n_e) where life emerges
f_i = Fraction of habitable planets with life where intelligence evolves
f_c = Fraction of planets with intelligent life capable of interstellar communication
L = Years a civilization remains detectable

You see, it’s so easy to calculate the number of alien civilizations in our galaxy! Hahaha..just kidding. The Drake Equation appears extremely pleasing on a piece of paper but is unrealistic (according to me). So do we conclude that we’re alone? Not so early.. We are probably forgetting about The Fermi Paradox.

The Fermi paradox is named after physicist Enrico Fermi, which is the apparent contradiction between the lack of evidence and high probability estimates for the existence of extraterrestrial civilizations. It is a conflict between probability and evidence. It also states that we could be protected under a shield that does not allow us to contact other intelligent beings.