The Drake Equation attempts to quantify how likely we are to find intelligent alien life.
It takes all of the variables required for an intelligent civilization to exist AND send out communication signals, then multiplies them together.
The values of the variables on the left side of the equation are skyrocketing the more we explore the universe with telescopes and satellites. We’ve found far more star systems and planets capable of hosting life than we ever thought possible. Some estimates are as high as 60 billion planets in the Milky Way!
But the N value (the estimated number of alien civilizations in our galaxy capable of communication) must still be small because…well…we haven’t found them yet!
That begs that question — which of the variables on the right side, the unknowns, are the great filters causing that small N value?
The most critical variable to us on Earth is the last one. L is the length of time civilizations release detectable signals into space.
If L is responsible for the small N value, it could mean that species don’t often last long enough to create signals, let alone receive them. It would then stand to reason that the near-term destruction of our species is statistically probable.
SETI researchers hope that, instead, the great filter is behind us. Perhaps the emergence of intelligent life is the rare occurrence rather than how long those lifeforms survive.
Or maybe the Drake Equation is incomplete.
Maybe they have some Star Trek-esque ideal of never meddling with the growth of early-stage civilizations.
Maybe they are out there listening, but they’re so far away that our signals won’t reach them for centuries, and their replies will take just as long to hit our digital ears.
Maybe they’re so much more advanced that we’re just not that interesting to them.
…or maybe we’re one day away from receiving a reply.