NASA’s theory about the lack of alien visitors is truly depressing

Paper embraces the Great Filter theory of civilisations wiping themselves out before they can leave their planets.
Hello? Is there anyone out there?
Owen Humphreys/PA
Alan Martin15 November 2022

Our galaxy has around 100 to 400 billion stars in it, and there are around the same number of galaxies in the universe. If even a fraction of these stars replicate our sun and have planets with Earth-like environments orbiting them in the so-called “Goldilocks zone” (where it’s warm enough for water to neither freeze nor evaporate), then there could be billions of planets out there that support life.

And yet we haven’t heard a definitive peep from anything beyond our planetary postcode [despite various reports of “Unidentified Aerial Phenomena” (UAPs)]. This is known as the ‘Fermi Paradox’, and the latest research paper from NASA embraces the most depressing of the available explanations known as “The Great Filter”.

In short, that theory posits that life in the universe is ‘filtered out’ (a nice way of saying it becomes extinct) before it can contact others. The most depressing reading of this is that it’s simply the inevitable fate of any species evolved enough to try and make the jump to become an interplanetary species: the advancements ultimately kill it.

And that’s the crux of NASA’s latest paper (Avoiding the ‘Great Filter’: Extraterrestrial Life and Humanity’s Future in the Universe) which examines the likely imminent threats to our civilisation, considering each one a possible filter that’s coming for human life, just as it may have for other species elsewhere in the cosmos.

“The key to humanity successfully traversing such a universal filter is… identifying [destructive] attributes in ourselves and neutralising them in advance,” reasons the paper. The key threats? Nuclear war, pandemic, climate change, and uncontrolled artificial intelligence.

“History has shown that intraspecies competition and, more importantly, collaboration, has led us towards the highest peaks of invention,” the paper concludes. “And yet, we prolong notions that seem to be the antithesis of long-term sustainable growth. Racism, genocide, inequity, sabotage... the list sprawls.”

Although, the paper concedes, contact with other species could, in itself, have catastrophic consequences. “There is no guarantee what kind of relationship would develop with beings so cryptic and distant from ourselves,” the paper reads. “First contact may very well abolish our fragmented society, especially the scattered and fragile coalition in which humans have organised themselves.”

Why haven’t we met aliens? The other possibilities

Space, the final fromtier
NASA

It’s worth highlighting that there are other theories as to why we haven’t met alien life yet — some more ‘glass half-full’ than others.

One is based on the Great Filter theory outlined above, but suggests we’ve already passed through it successfully. If this is correct, the lack of others reaching out would suggest it’s vanishingly unlikely, and maybe there just isn’t any other life out there that has achieved this amazing feat.

Another option is that aliens have already made contact with Earth and we just didn’t notice. Just because we use radio waves for communication, there’s no reason to assume another species would, and such correspondence may exist in a format that’s invisible to humans.

Or alternatively, another species could have made contact before human life arrived to document its arrival — something not altogether unlikely, given we’ve only been around for about 0.0001 per cent of our planet’s 4.5 billion-year history.

There’s also the possibility that life is out there and deliberately hasn’t made contact. That could be for mundane reasons (cosmically speaking, we could be out in the sticks) or more sinister ones (the universe could be more dangerous than we naively think and species that have survived have done so by not broadcasting their existence).

On the more far-out end of the explanations, there’s the suggestion that this could all be a simulation or that we’re a kind of intergalactic zoo being observed from afar and deliberately not interfered with.

In short, there are many explanations as to why we haven’t met another species yet. But, even if they’re correct, it would still be sensible to heed NASA’s advice and do everything we can to avert nuclear war, another killer pandemic, and catastrophic climate change. It may not help us meet aliens, but it could help secure humanity’s future for generations to come.

Or as NASA puts it: “There is no known theoretical limit to how far humanity could progress into the distant future, this given the effectively inexhaustible supplies of matter and energy which lay beyond Earth’s fragile atmosphere in a Universe with far more time ahead of it than the mere 13.8 billion years which have already dropped into its past.

“Humanity evolving to a Type II civilisation, and even to Type III, is not beyond possibility. To prepare for our journey, we can likely count on the inner Solar System remaining habitable for another few billion years, until the Sun begins to expand towards red giant status. Time enough for humanity to finally make other stars our home.”

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