Mars, the red planet, is the closest planet to us and is therefore the most similar out of all the other celestial bodies in our Solar System. In fact, Mars is so similar to Earth that scientists believe there is a good chance of finding some evidence of life on its barren surface. The chance of discovering that life originated independently on another planet so close to us is rather exciting, but we can’t afford to be naïve. Obviously, extraterrestrial life is a concept we can’t have a well-founded opinion on, because our ignorance outweighs our knowledge. It would be a tremendous discovery for mankind, no doubt, but some scientists believe that it would have major ramifications for life on Earth.
Nick Bostrom, The Director of the Future of Humanity (yeah! that’s a thing) at Oxford University says that, “Such a discovery would be a crushing blow. It would be by far the worst news ever printed on a newspaper cover. No news is good news.”
But why is that? To answer this question, we first need to understand why we’re alone.
It is natural to wonder about our place in the Universe and how we fit into the grand scheme of things. It could be possible that life on Earth is a unique occurrence and that we are the most, possibly only advanced civilization in the universe. However, this possibility is very small, simply because of the sheer size of the universe. As many stars as there are in our galaxy (100 – 400 billion), there are roughly an equal number of galaxies in the observable universe. In other words, for every star in the colossal Milky Way, there’s an entire galaxy out there, many of which are larger and more impressive than our own.
Around each of these trillions of stars are numerous planets, and we have to be inconceivably arrogant to think that Earth is the only one that can support life. However, since there is no proof of extraterrestrial life and there haven’t been any attempts to contact us, we can’t help but wonder where everyone is! This question, as perplexing as it is interesting, is called the ‘Fermi Paradox’.
The process of answering Fermi’s question has generally divided the scientific community into two separate groups.
The First Group thinks that there are no civilizations more advanced than us. Since their technology isn’t more advanced, they can’t contact us, just as we can’t contact them.
The Second Group believes that other advanced civilizations do exist, but they haven’t contacted us for a variety of inconceivable reasons.
If we believe the first group, then the only way there currently are no advanced civilization is that they are already extinct. This leads us to believe that somewhere during their development, they faced catastrophic odds that they couldn’t beat. This cataclysmic event in the life of a civilization is called the ‘The Great Filter’. Whether a civilization can advance further and survive extinction is determined by whether it can survive this Great Filter. It could be anything from a nuclear apocalypse to a meteor impact or any other extinction-level event. This leads us to three explanations:
Reason 1: We are rare and there is no Great Filter
This is especially arrogant, because statistically speaking, Earth can’t be the only planet supporting life out of billions and billions of similar planets. Therefore, most scientists don’t use this reason to explain the paradox.
Reason 2: We are the first to have passed the Great Filter.
This is relatively more believable than Reason 1, but still very unlikely. Life on Earth originated 3,500 million years ago, while humans have only been a part of its history for the last 300,000 years. This is a fraction of a blip in the timeline of the Universe. If there had been civilizations on other planets, it is almost certain that some of them have a lead on us by millions of years. We all know what even a century’s worth of technological advancements can do for a civilization… can you imagine what a million-year-old civilization might be capable of? The assumption that we are the first civilization to have passed the Great Filter means that this Filter event occurred somewhere in the past. That being said, there are a lot of Great Filter candidates in our history.
The evolution of complex eukaryotic life from single-celled organisms took about 1.8 billion years to occur. It is possible that the difficulty implicit in this evolutionary jump is a Great Filter and that on other planets, this leap couldn’t happen. The meteor that hit the Earth in the Cretaceous era, when dinosaurs walked the Earth, could be another Great Filter candidate.
Reason 3: The Great Filter is still to come.
Most scientists believe that this is most likely the reason why we have found no other civilizations out there. If we haven’t yet faced the Great Filter, that would almost certainly mean the end of our civilization. If the Great filter is still down the road, it would mean that each and every civilization progresses only up to a certain level, after which it faces its downfall. There could be a variety of Great Filters, such as running out of resources and energy, self-induced destruction, ill-meaning artificial intelligence etc.
Now, since Mars is rather close to us and similar to us in many ways, it can be safely assumed that life on Mars would have gone through similar conditions as we did. If we find that life once existed on Mars, then it doesn’t bode well for us. The discovery of extinct multi-celled organisms on Mars would indicate that the evolution from single to multicellular organisms wasn’t in fact a Great Filter. Similarly, a discovery of extinct complex life forms on Mars would indicate that most of the filters in our history aren’t the major Great Filters either, and that we still need to face the actual Great Filter at some point in our future. The more complex the life we found, the more depressing the news of its existence would be. It would be scientifically interesting, certainly, but also a bad omen for the future of the human race. We can be hopeful, but odds are, we wouldn’t be able to survive the Great Filter down the road.
Bostrom believes that when it comes to the Fermi Paradox, “the silence of the night sky is golden.”