The calculation aimed to estimate how many civilizations could communicate with one another. The result wasn’t a single number, but a range of possibilities.
A document from a U.S. intelligence agency examined how to estimate how many civilizations could send and receive messages across the galaxy. Rather than offer a single number, it proposed calculating a range of possibilities.
It means civilizations that could send and receive messages.
No. It proposed a way to calculate a range of possibilities, and its examples were meant to illustrate the method.
The document was intended as a reference for later analysis. The series covered a range of topics, not all of them directly related to space or threats.
In 2010, the U.S. Department of Defense’s intelligence agency prepared a document on a question that sounds like science fiction: How many civilizations in the galaxy could send and receive messages? The document offered no single number. Instead, it proposed a way to calculate a range of possible answers.
What’s surprising is that the document didn’t pretend we know more than we do. It argued that some of the data needed for the calculation are uncertain. That means the possible distance between neighboring civilizations can’t be given as a single figure, either. But why was an intelligence agency considering this question at all?
The document presents the Drake Equation, a way to estimate how many civilizations capable of communication might exist in the galaxy. It relies on several questions, including how many stars there are and how many might support life.
The document was intended as a reference compiling knowledge on the subject for use in later analyses. According to the official summary, the series covered a range of supporting topics, and not every document dealt directly with space systems or future threats. That explains how a broad question about the galaxy found its way into an intelligence agency document, without making it an official answer about whether life exists.
To estimate how many civilizations could communicate, you need to plug in values for the stars and the possibility of life. But some of those factors can’t be pinned down with certainty. Choosing a single figure for each could make the result seem more precise than it really is.
So the document proposes using ranges of possible values. Instead of one answer, you get several possible results. The same idea applies to the distance between neighboring civilizations: that, too, is better described as a range than as a single number.
The document includes examples showing how the method might work. They use assumed values, not data proving how many civilizations exist. So the examples offer no reliable estimate of how many civilizations are in the galaxy; they demonstrate the method, not establish the result.
The document doesn’t determine how many communicating civilizations exist or where they are. Nor does it reliably estimate the likelihood that they exist or the distance between them.
There was no point on the map of the galaxy to point to. All that remained were possible distances—and a question with no address yet.