NASA scientists offer a theory as to why we haven’t encountered other intelligent life. It’s crushing.

NASA scientists new paper Why they believe it’s likely we’ve never encountered intelligent extraterrestrial life – and it’s heartbreaking.

They argue that all intelligent life forms presumably destroyed themselves before reaching a sufficiently advanced evolutionary point to support such an encounter. And they believe that the same fate likely awaits humans unless we take action.

Similar to “filtering out” various forms of life, the “great filter” theory claims that other civilizations, possibly several, have existed during the lifetime of the universe. But they all self-destructed before they made contact with Earth, the paper notes.Avoiding the ‘Great Filter’: Extraterrestrial Life and Humanity’s Future in Space

Scientists fear that there is a deep-seated dysfunction in all intelligent life forms, including humans, that could “snowball rapidly into the Great Filter.”

But humanity still has a glimmer of hope, according to a paper published by a team of researchers based at NASA’s Jet Propulsion Laboratory in Southern California.

“The key to successfully passing humanity through such a universal filter is… [destructive] Astrophysicist Jonathan Zhang and his co-authors wrote in a paper published online Oct. 23.

This paper has not yet been peer-reviewed.

The authors argue that what seems likely to destroy humanity could also threaten intelligent life on other planets. Possible culprits affected by humans and other intelligent life include nuclear war, pandemics, climate change, and uncontrolled artificial intelligence, the authors point out.

The trick, the biggest challenge of all, is working together to survive, researchers say.

“History shows that intraspecific competition, and more importantly, cooperation, has brought us to the pinnacle of invention. It prolongs concepts that seem to be the antithesis of: racism, genocide, inequality, sabotage, etc.,” warns the author.

check out Full paper here.

This article originally appeared on huff post and updated.