Are we alone in the universe : A rough idea

Different people have different ideas and logics about the existence of life elsewhere in the Universe. It is an old age question, yet to be answered. Even scientists and astronomers have different views. Some believe and have logics and proofs of extraterrestrial life, but others also have their own doubts. Various incidents reported in near past and the data collected by NASA and other space exploration Agencies indicates the presence of extraterrestrial life but nothing has been proved or certified.

Before we ask the same old age question to ourselves, let us theoretically calculate the possibility of extraterrestrial life. For this we must know some facts:

• Our Earth is a very small tiny dot in the milky way. We can hardly see it with naked eyes.
• Our galaxy Milky Way contains approximately 100 billion stars along with planets orbiting them.
• As we travel further into space, the entire galaxy becomes just a dot of light called clusters.
• These clusters contains millions of galaxies. some of them like radio galaxies, spiral galaxies are far more larger than our Milky Way.
• According to Big Bang Theory, the universe is still expanding. Universe contains uncountable stars and planets. We can only imagine the boundaries of the universe.

The size of the universe is beyond our imagination containing billions of stars and even more planets orbiting those stars. So there is a greater possibility of existence of life somewhere else in the universe also.

Although, some life supporting elements also required for its existence like water, but as we now know that water is present everywhere in the universe in some form or the other. Here on earth, some microorganisms called extremophiles thrive in physically or geochemically extreme environments that are detrimental to the most other life on earth. Humans on earth share the planet with as many as 8.7 million different forms of life. Recent researches shows that life is possible in a completely different environment and conditions.

Albert Einstein postulated the theory parallel universe. If we are able to prove it some day and make it possible to move from one universe to the other parallel universe, we might see several different forms of life there.

We are living in four dimensional (length, depth, height and time) world. It has already been proved that there are number of other dimensions in the universe. According to superstring theory, there are at least 10 dimensions in the universe (M-theory suggests that there are 11 dimensions; bosonic string theories suggest 26 dimensions). So, not surprising to hear some day, that we are living with unknown life forms in the same spacetime.

So, now we have a rough idea of the possibility of extraterrestrial life in the universe containing uncountable planets, with variety of different forms of life and the ability of living organisms to exist in extremely harsh and different environmental conditions. We can assure ourselves that we are not alone in the universe. 

We can have contradictory views on whether the life that exists elsewhere are primitive or Complex, unintelligent or intelligent, on the shape, size, looks and the chemical composition of the living organisms. But one thing is certain that extraterrestrial life does exist and we might be able to find one of them in future.