Updated: Oct 31, 2022
From the inception of intelligent human life on earth , humans had been so fascinated by the cosmos . We have archeological evidence that shows depiction of space,stars and the zeal of early humans to reach there.
Life as we know it came to existence on earth around 4 billion years ago in the form of a single celled organism and with time evolved into many complex sophisticated life forms that we see around us.
What makes life happen?
Scientific studies have pointed out the inception of biology from chemistry, known as Abiogenesis i.e; chemical combinations in the presence of proper physical conditions give birth to life on earth. So was it uniquely limited to earth or it was common , as it was described that life on earth occurred spontaneously when the conditions were favourable i.e; Liquid water , sufficient light and heat , abundance of chemical molecules. These conditions made it possible for us to get started. During the initial stages of our universe , the temperatures were quite favourable for life to exist on different cosmic systems . When the Universe came into being 13.8 billions years ago after the big bang , the universe was similar to a hot oven , there were primitive molecules of gases like hydrogen and helium . There were primary stars spread everywhere in the universe and these stars became home for the birth of other elements ( Carbon, Oxygen , Sodium , Nitrogen etc ) that are necessary for life . When these primary stars exploded , different solar systems came to existence with solid planets revolving around comparative small stars and at this time around 13.7 billion years ago , the conditions became favourable for life . Life may have started at some spots but for the universe the ultimate goal is not seeding life . It is always moving ahead in the arrow of time towards an increase in entropy (randomness).
It means that the universe might have provided windows of small duration of around some millions to billion years (comparative to its own age) for life to rise , evolve and then ultimately get extinct. These windows had suggested the existence of life in waves . Even on earth , life emerged several times and ended and then at one point it survived and evolved. When we denote the existence of life in cosmic history, we do not mean the complex human-like intelligent life forms but simple biomolecules, unicellular organisms .
Life, in this form thus had genesis across the universe for small time windows till the conditions become unfavourable due to some cosmic disasters . These disasters ranged from cosmic collisions to exposure to the dangerous flares of stars to asteroid attacks, to star exploding and destroying all the planets revolving around or a black hole consuming the complete solar system In all these scenarios, life started in unique zones around the stars known as goldilocks zone where the planet was in a balanced proximity to the star, nor so far to get frozen, neither so near to get 1000* C of temperatures.
So life might have existed and may be thriving somewhere else right now , and the mathematics supports the argument of life thriving and evolving but the question is All of the time, On all the Planets of all the galaxies in space, which civilisations have risen, looked into the sky , and asked the question that we ask : Are we alone ? Are there advanced alien civilisations out there, with sophisticated and developed technology? The only convincing response is WE DON’T KNOW.
Our information and knowledge about the cosmos is so limited and our reach is even more limited. We have our telescopes searching deep space and identifying habitable Earth-like planets by studying the characteristics of light waves that we collect from these exoplanets . And the data from SETI institute, the premier body in Search of Extra-terrestrial Intelligence suggests that there are around 300 million potentially habitable planets present in our own galaxy and there are around 200 billion galaxies in this huge universe .
So there are some potential chances and Frank Drake , an Astronomer and Astrophysicist tried to give these chances a mathematical figure and gave an equation to calculate the chances of existence of life on any particular cosmic body. The formula is famously known as Drake Equation.
According to the equation, there are 60-70% chances that life may exist in some habitable planets according to the values of variables in the equation.
But why did the earthlings haven't received any guests yet ? This answer is life does not just need mathematical chances to advent and thrive but for some highly advanced alien star faring species to exist anywhere in the universe, the life supporting conditions must be more or less constant across a long duration of time because evolution of a primitive species to a highly intelligent species requires the genome of the species to undergo changes and it takes millions to billions of years .
Today with more or less empty hands, we can’t openly deny that we humans are the lone wolf in the whole universe but still with limited available information we didn’t find anything remarkable to suggest the existence of life . The upcoming decades will be very crucial with advancement in technology and arrival of private players in the field. The age-old question of l requirements and life to survive and grow.
So life in this form is rare , extremely rare . Our scientific community, as per the data available to us , also argues that there are probably zero advanced civilisations other than us in our galaxy but there might be life somewhere in an underground sea of some exoplanet . Even our own solar system still awaits to be explored completely. Mars, the very next planet to us, has ice just below the surface sand .
Enceladus -A moon of Saturn has a completely liquid ocean below it’s thick ice surface of around 30 miles . These places might be a potential host of life or been a host at some point of time and then the conditions become unfavourable. But for us humans, this is still our advent as a great civilisation . As being quoted "Mankind was born on earth. But it was never meant to die here "
Today we are at the verge of becoming a multi- planet species. Elon Musk's SpaceX and Jeff Bezos' Blue Origin and NASA planning to colonise the moon and mars in the upcoming years is going to be a great leap for humanity and will open a new quantum of possibilities for human kind . We may find our next cosmic neighbour in the next 100 years or so with the space exploration projects of NASA and SETI and the visionary Breakthrough initiative project making a leap in the studies of cosmos with the highly advanced AI technology enabling high rate data analysis.
Today with more or less empty hands,we can’t openly deny that we humans are the lone wolf in the whole universe but still with limited available information we didn’t find anything remarkable to suggest the existence of life . The upcoming decades will be very crucial with advancement in technology and arrival of private players in the field. The age-old question of Are we alone , will even then remain a mystery till we find a hidden abode of life thriving in some corner of this cosmos.