In the vastness of our galaxy, how many technologically-advanced civilizations are out there?
In 1960, astronomer Frank Drake asked this very question. He didn’t know, either, but he sat down and figured out the things you’d probably have to know in order to figure it out. And in doing so, he unknowingly influenced the future of science-fiction television. Here’s the result of Drake’s pondering:
N = R* x fp x ne x fl x fi x fc x L
This formidable-looking formula became known as the Drake Equation. It’s actually easy to understand the basics, even if it’s impossible for present-day scientists to solve.
Drake simply figured that in order to know how many technological civilizations are out there, you’d first need to know the number of stars presently in the galaxy. You’d then need to know what fraction of those stars have planets. Then, the average number of planets orbiting those stars. Then, the fraction of those planets that could support life. Then, the fraction of those planets that actually do have life. And so on. You get the idea.
Since we really don’t know most of these values yet, there’s no way to come up with a definitive answer to the Drake Equation. Naturally, some astronomers have tried. They plugged in their best guesses, which of course vary widely. The resulting estimates range from zero to 5,000 and more technologically-advanced civilizations in our galaxy. And, of course, as astronomers continue to study the cosmos, they're gradually developing more realistic estimates for some of those values. (Professor Drake’s personal estimate is about 10.) The real answer, of course, is that we simply don’t know. Yet.
Oddly enough, the Drake Equation played a role in the early development of Star Trek. When Gene Roddenberry wrote the first outline for his proposed series back in 1964, he was concerned that the notion of life on other worlds might not seem credible to the average television executive. Roddenberry had apparently heard of the Drake Equation and wanted to mention it in the outline as proof that real scientists took extraterrestrial life seriously. Unfortunately, he didn’t have a copy of the actual equation handy.
Roddenberry explained in Stephen Whitfield Poe’s 1968 book, "The Making of Star Trek": “I asked a friend of mine at Caltech to look it up for me, but in the meantime I wanted to see how it might look on paper. So I just made up a complex-looking formula to visually give me an idea how it would look. Before I could get back to my friend at Caltech, MGM began asking me for the ('Star Trek' series) format (document). My secretary typed it up the way it was.”
Roddenberry went on to admit that he never got around to fixing his fake equation, which eventually became widely published as part of the Star Trek format. He noted: “I got busy with other details and forgot about the phony formula. Now, years later, no one — scientists, mathematicians — no one has ever questioned that formula!”
Some 30 years later, "Star Trek: Voyager" did an episode called “Future’s End,” which was set on Earth in the year 1996. One of the characters in the episode was an astronomer named Rain Robinson (played by Sarah Silverman) who was searching for signs of intelligent life on other worlds. I figured that she might have a copy of the equation up in her laboratory. Since this was Star Trek, I thought it was also appropriate to display the Roddenberry version of the Drake Equation. The result was this small placard, which can be glimpsed in the episode.
Drake was kind enough to chat briefly with me during preproduction for “Future’s End.” I asked him a couple of questions about the search for extraterrestrial intelligence (SETI) for the episode. During the conversation, he asked to see the Roddenberry Equation. He seemed amused that he had played a behind-the-scenes role at a pivotal moment in Star Trek history, but he gently reminded me that any number (like C or Ri) raised to the first power is exactly the same as the original number. I’m sure that Roddenberry would have been honored to be corrected by Drake himself!
For information on the Drake Equation and the search for extraterrestrial intelligence, check out the SETI Institute.
© 2015 Michael and Denise Okuda.
Astronomer Frank Drake's equation about life on other worlds influenced the future of science-fiction television.