LIFE BEYOND EARTH

There are questions to which knowing the answer would have a profound cultural effect. The question of our solitude is one. Are we alone in the universe - Yes or No ? The question as I posed isn’t a good one, because it is impossible to answer it in affirmative. We have no chance even in principle of, exploring the entire universe, which extends way beyond the visible horizon of 46 billion light years away. A staggeringly large number right, I know when it comes to space the scale starts inflating exponentially. The answer can therefore never be yes with certainity. The question ‘Are we alone’ is not new, from past two to three millennium or so many natural scholars and philosophers across ages stumbled around this question and more interestingly civilisation which are acheologically dated back 3900 BCE noticed this question arising in their head. Some of the ancient civilisations such as EGYPTIAN, MAYAN, BABYLONIAN, SUMERIAN, HAWAIIAN, MESOPOTAMIAN etc are seperated by centuries but forecasted the same question.

Is life on earth special ? Or is it one of billions of life forms across galaxies ? But first of all how should we define life. According to NASA the defination of life is LIFE IS A SELF SUSTAINING CHEMICAL SYSTEM CAPABLE OF DARWINIAN EVOLUTION. This phrase is so refreshing but packs a lot in few words. The first part self sustaining is clear enough but the second part ‘ capable of darwinian evolution’ hides a lot of details. It means that the self sustaining chemical system must be capable to evolve or change over time. First there was an assumption that change occurs over successive generation each of which born, grow and then die. Then there is the word Darwinian named after Victorian naturalist CHARLES DARWIN, the man who shattered the conventional notion of the world about the creation of mankind forever. I will talk about the debate between Creation vs Evolution in a later blog. He argued that organism evolve for a reason - to adapt to the changing circumstances of their environment - by means of Natural selection or Survival of the fittest. The beauty of this defination by NASA is that it encompasses everything from single celled organism that emerged on earth 4 billion years ago via semi civilised primate like ourselves, all the way up to the super advanced life forms we can hardly ever imagine.

So is life on earth special ? I don’t think so. Now everybody have their own philosophy about life and its importance but I personally do not believe that life on earth is actually special. Well our own milky way galaxy is spread approx 105,700 light years in diameter( 4.6*10^17 km) which is pretty hugh right. Compare it with the diameter of our solar system ( 287.46*10^8 km ). That means 10^9 or 10 billion solar systems like us can be fit in the milky way. So the probability of finding another life among these 10 billion solar systems is really high and that to in our own galaxy. An Astronomer named FRANK DRAKE tried his hands on it. He focused on a well defined question “How many intelligent civilisation exist in our milky galaxy that we could in principle communicate with ?”. Drakes brilliant insight was to express this in terms of a simple equation containing a series of probabilities. It is a very famous equation called the Drake equation in astrobiology. I will go deep into this equation in an another blog.

There is a lot to travel in this topic. A request from my side, while reading this blog go on imagining along with it. It will be fun.