Frank says that discovering planets and stars is easier for humans than ever before, so we have way more of an understanding about cosmic galaxies than ever. This means that “interstellar communication,” or being able to communicate with extraterrestrials, depends on how many extraterrestrial civilizations exist.
Here’s the math: scientists have found that every star likely hosts at least one planet; we know how many stars are born each year, and we know that between 20 and 25% of all planets can host life.
That makes it much easier for Frank and Woodruff to determine if Earth is the only technological civilization in the galaxy.
Their theorem dictates that it’s not. According to Frank, other technological civilizations definitely existed in the past.
The scary part? “According to ourfinding, even if you grant that level of pessimism, a trillion civilizations still would have appeared over the course of cosmic history,” he says.
A trillion aliens? Now, that’s worth an Ancient Aliens episode.