Maybe they just don’t like our faces. Given the sheer, incomprehensible size and complexity of the Universe, it becomes almost impossible to believe that the Earth is the sole planet that fosters life. We have been very limited in our capacities to explore the Universe – we have barely made it out of our own Solar System properly. But if there is life out there, why isn’t it searching for more of itself like we are?
Like all good scientific discussions, we will break this down into a few points –
- Maybe there is no life at all, and we are the only freak product of a series of coincidences
I, personally (along with many others,) find it highly unreasonable, but good science takes everything into consideration, especially when this is actually the theory that has a lot of evidential support. You have to realize that the specific conditions required for (Earth) life are very, very, very particular. Even with the vast playing field outside, it is very unlikely that life as we know it is thriving somewhere else. Associated with this point is the understanding that perhaps life outside the Earth does exist – but in unintelligent forms, such as bacteria or amoeba. They won’t be calling on us anytime soon, unless brought in by celestial objects such as meteors.
- Intelligent life forms, like us, may not have developed the tech for interstellar travel yet
Of the three billion species on our planet, only one has developed the capacity for spaceflight, and even we started doing this, what, fifty to seventy years ago? The timeline of the modern humanity spans back nearly 60,000 years, and only now have we looked up at the sky and began making machines to explore it. Perhaps others beyond our system are at the same place in history that we are; perhaps they are a few centuries behind us. Thus, it is likely that technologically advanced species are rare across the universe, and that they all need more time before they say hi to each other.
- The Universe is simply too large, and the civilizations are separated by too much time and space
In case you haven’t heard yet, the universe is mind-bogglingly large. Today, the Voyager 1 is the man-made probe that has gone the most distance in space, so much so that it has escaped the Sun’s clutches and is now in interstellar medium (the space between the stars). Say that, by some miracle, it doesn’t get destroyed even after it no longer works, and some alien life finds it, some 12 light years away (the nearest estimate of life beyond the solar system). They look in wonder at the images of humanity that NASA has provided in the craft, and decide to visit us. Only, we have gone extinct by that time, because one light year is about 9.5 trillion kilometres. You can only imagine the time it would take to cover such a distance. Even if in the future we manage to detect some alien life (or some alien life finds us), we may never be able to engage in meaningful contact before one of us dies out.
- They may be trying, but we may not be listening
Earth has began looking for signals from outer space only since the early 1940s. It may not be enough time, given the expanse of the Universe and the distance between habitable planets, for something to reach us. It may also be that alien technology and ours may be incompatible, and thus the signals they send go right over our heads, literally and figuratively. This is one of the major theories that has pushed for diversification in space technology, and is also a hopeful theory because it suggests that if we keep waiting and improving, we may get a friendly hello any day soon.
- It’s Gravity
This simple theory, proposed this very year, is quite simplistic yet very probable. In our search for other planets, we have found many habitable ‘super-Earths’ – planets just like Earth, but much larger in size. This naturally means that these planets will also have a much stronger gravitational pull. Thus, it may be likely that the life on these planets may want to go out exploring, but they simply don’t have the power to escape their planet, because there simply won’t be enough mineral fuel to power the rockets. This makes the number of planets that can achieve spaceflight limited. So perhaps, humanity will have to go knocking.
- We are little babies that aliens observe but don’t interfere with
If the timeline of the Universe was condensed into a single calendar year, the earliest ancestors of humans would have arrived on 30th December, agriculture would have started on 31st December at 11:59 and 23 seconds, and modern era, including all our space efforts, began at 11:59 and 59 seconds. This young age of humanity has led some to propose the Zoo Theory, which suggests that humanity is under observation by more advanced civilizations that have a policy of no-interference, and they may initiate contact when we are ready.
What we have been discussing up till now – the paradox of a large Universe with an endless number of planets yet no signs of alien life – is known as the Fermi paradox, and there are countless other explanations for it, ranging from the most scientific to the most conspiratorial in nature. Till we find some concrete answers, our conjectures will continue, and perhaps it is only a matter of time till we find out which of the theories stand true.
By Niharika Rawat