Written by: Fuad Kehinde, Science Editor
Are we alone in the universe? A question that has been asked for centuries, and yet, we don’t seem in any way close to answering. Looking out into the beyond of space and searching for beings like us seems to be a unifying human experience. Throughout the centuries (most significantly the last century) there have been countless efforts to communicate with alien life. From sending radio waves out into the abyss to the Voyager Golden Record (NASA literally sent a disc with information into space. This information included pictures/sounds from the earth, our co-ordinates and even music.).
After all this searching, sending and listening, why have we yet to communicate with anyone? Are we truly the only intelligent beings out there? As countless habitable planets have existed over the last few billion years, that means life has had plenty of chances to develop. So, it seems pretty unlikely that we’ve yet to encounter another intelligent species, right? This issue is known as the Fermi Paradox and it is yet to be solved. The question this paradox proposes is, why does it seem like we’re alone in the universe?
How have theorists attempted to resolve this issue? A very popular proposed solution is that of filters. Filters are like barriers to the development of an intelligent species. They’re issues that intelligent life must beat in order to continue to progress. An early filter would be the evolutionary leap from single-cell life to more complex multi-cellular life. More recent filters would be Nuclear War or Climate change. So, with this idea of filters and the knowledge that the universe seems empty, it can be presumed that there exists some major, deadly filter which I’ll call the great filter.
The great filter would be a filter of such magnitude that it destroys all species that make it to it. If this great filter exists, then there are two possibilities. The first possibility is that we’ve already passed it. If so, that would mean that humanity was fortunate in passing this filter but also that we are alone because no other species has managed to make it this far. The scarier possibility is that the great filter is ahead of us. Maybe we are destined to create some super technology or advanced bioweapon that annihilates us or sets us back by a considerable margin. There’s no real way to tell which of these possibilities is more likely.
Another proposed solution to the paradox is that there already exists a super-advanced civilisation. There could exist a species that has advanced to the point where it controls entire solar systems. Maybe they constantly scan the universe until they find a developing society like ours, then stop us in our tracks. Possibly to keep a hold on their unrivalled control of the galaxy.
Or maybe there are many non-hostile alien species, but our means of communication are far too primitive for them. We could be like an isolated home in a massive forest that is only equipped with a Morse code transmitter. No matter how much we communicate and send out signals, no-one is going to be looking out for such a primitive form of communication, right? So, if we’re sending out signals solely from that forest, it would seem like we’re all alone.
Perhaps, the most boring but equally valid solution is correct. We are truly all alone in the universe. We do not yet understand the conditions that complex life, and thus intelligent life, needs to develop or even the likelihood of it happening in the first place. Maybe existing as we do is virtually impossible. Maybe evolving big brains is not something any other species has done. Again, we cannot answer these questions until we have more developments in the field.
Personally, I think the effort to solve the Fermi Paradox is far more interesting than any possible solution. Why do we try so hard to prove the existence of intelligent life? Is it for when Earth is long gone, our existence is somehow justified by another species knowing about us? Is it a need to find species that, like us, can observe and appreciate the beauty of the universe? Or is it just a thirst for knowledge that finding aliens can satiate? No matter what it is, the wonder that we indulge in when we think about aliens is something that I think powers scientific interest and discovery. It is through what is practically science-fiction that many people, including me, find our passion for science. Like the great Carl Sagan said, “Imagination will often carry us to worlds that never were. But without it, we go nowhere.”.