"Where are the aliens?"
“Where is everybody?”
It was the summer of 1950. The setting was the Los Alamos national Laboratory,
New Mexico. Enrico Fermi, the Italian-American physicist, and his friends were having lunch.
The topic of discussion ranged from flying saucers to aliens stealing trash cans in New York city
to the high probability of faster-than-light travel.
“Don’t you wonder where everybody is?”
Although Enrico Fermi’s outburst was seemingly innocuous, it left in its wake an extraordinary
paradox that continues to baffle scientists even today, several decades after his death.
Fermi’s question, interestingly, was not intended to ask why his friends had not come for lunch,
but surprisingly, why earth showed no signs of extra-terrestrial life. Although the conundrum
got drowned in a babble of sceptical laughter, the incongruity between the lack of evidence of
extra-terrestrial life and the high probability of its existence has to date not been explained.
Over the years, several facts and hypotheses have arisen that have brought into focus the
apparent contradiction now known as the Fermi Paradox.
If you were to see the sky on any clear night, it would be ablaze with stars. While you would
estimate there to be a thousand stars, factually speaking, there are billions
and not thousands of stars in the Milky Way. And that is what gives rise to our first supposition.
With so many stars in the sky, the probability of some of these stars
hosting exoplanets or earth-like planets in a circumstellar habitable zone is quite high.
Scientists believe that many of these stars and their planets are quite old, much older
than the Sun. In fact, our Earth and our Sun are actually a part of a very young planetary system
as compared to the rest of the Universe. Thus, if our Earth, despite being so young has developed
intelligent life, it is entirely possible that other planets similar to earth may have it too.
So the question as Fermi aptly put is – “Where are the aliens?”
Although Fermi passed away unexpectedly in 1954, he left the behind Fermi paradox
that has been a heated topic of debate and discussion among the scientific community
as well as in the field of SETI – the Search for Extra-Terrestrial Intelligence.
Backed by SETI’s efforts to record radio signals or document mysterious fluctuations in starlight,
the only concepts supporting the theory of aliens visiting Earth is Fermi’s Paradox and
the Drake Equation which attempts to calculate the probable intelligent civilizations in our galaxy.
Is it also possible that if such civilisations do exist, they may have developed interstellar
travel? Something humans have been trying to accomplish for a long time, and are currently in
the midst of investigating. And if aliens exist and are capable of flying between the stars,
then a visit to Earth which hosts an intelligent life should not at all be inconceivable.
But the most convincing of these arguments states that since many stars similar to the Sun are
billions of years older, Earth should have already been the test ground for extra-terrestrial beings.
Unfortunately, there is no strong evidence that this has occurred.
However, the feasibility of the Fermi paradox has been explored extensively. It has been summarily
concluded that intelligent extra-terrestrial life is perhaps rare. Or maybe the lifetime of
such a civilisation has been shortened due to hindrances such as climate change, nuclear war
or some such reason preventing alien life to spread through the galaxy.
It is also possible that aliens have already visited Earth at some time in the distant past
and humans have missed it entirely. As far as interstellar travel is concerned,
could it simply be that it is either impossible or too far-fetched?
While our search for extra-terrestrial life has been going on for years,
our understanding of astrobiology is still in its nascent stage.
Perhaps there are aliens out there is the depths of the universe
silently observing the follies and foibles of the human race.
Or perhaps, we are indeed alone.