NASA scientists have a dark theory as to why aliens haven't contacted Earth yet

One of the mysteries that has fascinated humans for decades is the concept of intelligent extra terrestrial life - and now NASA scientists have given a dark reason which might explain why we have never encountered it.

In the paper titled Avoiding the ‘Great Filter’: Extraterrestrial Life and Humanity’s Future in the Universe that is yet to be peer reviewed, researchers Jonathan H. Jiang, Philip E. Rosen, Kelly Lu, Kristen A. Fahy and Piotr Obacz from NASA’s Jet Propulsion Laboratory in southern California have shared their theory as to why we have yet to come across other intelligent life forms.

To put it simply, they believe all intelligent life wiped itself out before being evolved enough to make contact with or encounter another civilisation such as Earth.

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This theory is called "the Great Filter," and in the new paper, scientists describe it as "phenomenon that wipes out civilisations before they can encounter each other, which may explain the cosmic silence".

Like ships passing through the night, essentially.

Scientists express concern over "sizeable challenges to overcome," for humans in order not to "snowball quickly into the Great Filter," if this filter exists.

In order to avoid this, researchers say that we must be aware of what factors put us at risk of distinction.

“The key to humanity successfully traversing such a universal filter is… identifying [destructive] attributes in ourselves and neutralising them in advance," the paper read.

Nuclear warfare, pathogens and pandemics, artificial intelligence, meteorite impacts, and climate change are named as some of the "multiple calamity candidates".

One of the biggest challenges for humans is to be able to work together for the sake of survival as researchers say "it begins with collaboration".

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

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