In a new paper published in the pre-print server ArXiv, a group of NASA scientists analyzed the 'Great Filter' theory, which posits that ancient alien civilizations may have wiped themselves out before they had any chance of making contact with humanity.The Great Filter theory is also a possible answer to the Fermi Paradox, which states that intelligent alien life should be abundant and detectable, given the fact that there are billions of planets located within the habitable zones of their solar systems in our galaxy alone."We postulate that an existential disaster may lay in wait as our society advances exponentially towards space exploration, acting as the Great Filter: a phenomenon that wipes out civilizations before they can encounter each other, which may explain the cosmic silence."Essentially, the paper's authors suggest that any existential threats we face here on Earth — including climate change, nuclear war, pandemics, and other factors — have likely been faced countless times by other civilizations over millions of years throughout the universe.Hanson suggested that many alien civilizations may have evolved to a point before they had the technology required to expand off-world, only to have then been wiped out."