“Two possibilities exist; either we are truly alone in the universe or we are not. Both are equally terrifying"

- Arthur C. Clarke

Are we alone in the universe?

Most probably not.

Let’s do the math. Come on. The Drake equation, a well known mathematical formula devised by Frank Drake, American astronomer and astrophysicist seeks to answer the aforementioned question. A simplified version of the equation is as follows;

N = R* × fp × ne × fl× fi × fc × L

N : Number of extra-terrestrial civilizations

R* : Average annual rate of star formation

fp : Fraction of stars that have planets

ne : Average number of planets that can potentially support life

fl : Fraction of planets with suitable environments to actually develop life

fi : Fraction of life that develops intelligence (civilizations)

fc : Fraction of life that emits detectable signals

L : Duration of emitted signals (in earth years)

N = 1,781,250,000,000 detectable intelligent civilizations in our Observable Universe.

Calculating N, we obtain an infinitely vast number of planets with the potential to create and maintain intelligent life. The exact value of N is not important as we are dealing with estimates that contain large uncertainties. It just gives us an idea that we might not be the only sapient civilization.

Now, what we have calculated above only indicates the existence of “comfortable” life. In other words, Drake’s equation only accounts for planets that exist in the Goldilocks zone of a star – regions which are neither too hot nor too cold, but just right. Besides that, there is a possibility that other planets inhabits extremophiles – organisms that survive under very extreme conditions; be it temperature or pressure. Let’s take a look at a typical extremophile on our very on planet Earth; the tardigrade popularly known as the water bear. A 0.5mm long eight-legged micro-organism which can be found almost anywhere; just name it – fresh water, moss, mountaintops, bottom of oceans, scalding hot springs and even at the polar caps of icy Antarctica. They can survive being chilled to almost absolute zero and heated to over 150°C. Surprisingly, tardigrades can tolerate exposure to the vacuum of space which has pressures a thousand times greater than earth's. They can even be reanimated after being dormant for centuries. The European Space Agency sent tardigrades to space first in May 2011. Two-thirds of their population survived the harsh conditions there – gamma ray bursts, solar radiation, insane temperature and pressure and cosmic rays. Some of the females even laid healthy eggs in space.

The Tardigrade 

This brings us to the theory of Panspermia. This proposes that primitive organisms survived space trips and colonised suitable worlds for themselves. So, probably, we are not actually Earthlings, but instead extra-terrestrial lifeforms ourselves.

In 1977, a SETI (Search for extra-terrestrial intelligence) volunteer came across the most fascinating intelligent frequency signal from outer space which lasted for seventy-two seconds. This signal was known as the WOW! Signal. It was ruled out as an earth signal reflected back by space debris. NASA (National Aeronautics and Space Administration) also ruled out the existence of a launched space probe at that particular direction. The signal never re-occurred. Are these seventy-two seconds enough to justify the existence of extra-terrestrial intelligence?

If we aren’t alone, why haven’t we found any proof?

NASA confirmed that space is not filled with Von Neumann probes (self-replicating space probes), stellar engines, signalling stations or other artifacts left behind by extra-terrestrials in space and neither have little green men with antenna landed at Area 51 to form an alliance. NASA claims to have really put in their best efforts in searching for signs of extra-terrestrial intelligence. Sadly, till date, there is no existential proof to their empirical existence. There are three most probable reason why;

1.   We are truly alone. Probably, Drake's equation is incorrect and he might have overlooked some Great Filter - something difficult to notice but essential for life for instance; for an intelligent civilization to occur, the planet of origin should have a satellite which is the exact size of our moon or a planet as big as Jupiter a considerable distance away to block incoming debris and protect it from planetary bombardment. Probably, there is an exact set of rules which must be reproduced perfectly and by sheer dumb luck, the Earth fits that criterion, making it the only planet in the Observable Universe to possess intelligent life.

2.   They lack intelligence. Life may be common but evolving complex intelligent life is not. This explains why we haven’t detected frequency signals or found alien structures in space and since space is infinitesimally vast, it would take a while before we discover them. This could also be seen as we being the first intelligent lifeforms in the Observable Universe – a few steps ahead of extra-terrestrials in the evolutional chain

3.   They are quiet or avoiding us. According to Russian theoretical physicist, Nikolai Kardashev, there are three classes of civilizations- Type I through to III. Type I civilizations are able to harness all energy available to them on their planet and use it effectively. Type II civilizations however, can encompass every inch of their home star, gathering all its energy and use it effectively. Type III civilization consists of the ultimate lifeforms. They become galactic travellers with knowledge of everything about matter and energy resulting in them being masters of the universe. Time travelling, immortality,  black hole manipulation and even expansion of space itself would be child’s play for such a civilization. According to Kardashev, man isn’t likely to reach the Type I class in this millennia. Probably, extra-terrestrial lifeforms are higher up than man in the Kardashev scale making it very easy to hide themselves. They may even transcend physical forms and decide to explore distinct realities. For all we know, there might be a prime directive set up by higher extra-terrestrials which forbids external interference with a developing civilization.

The Kardashev Scale

Even if we aren’t alone, is it in our best interest to try to communicate with extra-terrestrials?

Even though individuals and organisations have invested so much resources in the search for extra-terrestrial intelligence, some believe we should put a stop to that and let them be due fear that we may have different ethics and they might just end up pillaging the Earth either for resources or human slaves.

“If aliens visit us, the outcome would be much as when Columbus landed in America, which did not turn out well for the Native Americans"

-       Steven Hawking


1. WOW! Signal. Retrieved from

2. NASA (National Aeronautics and Space Administration). Retrieved from