This article was written by Frank Drake (of Drake equation fame) in 1961 and was published in Physics Today. It described the planning and execution of the first completed radio SETI observing program in history, the whimsically named Project Ozma. It also included a good deal of justification for why we might expect to find ETI out there – necessarily so, as this was the first project of its kind. Results? No aliens around Tau Ceti and Epsilon Eridani are broadcasting at the little slice of frequencies that were searched.
The search itself targeted 2 stars with 150 hours of radio observing time at Green Bank (I’ll admit, I’m jealous). They focused on the area around the 21-cm line. Since this paper, the 21-cm line became the most popular Schelling Point in frequency space, with the argument that the spin-flip frequency of hydrogen (the most abundant element in the universe) had to be the simplest universal watering hole. Whether that’s actually true, well, it’s hard to say – we human scientists agree that it seems like a promising place to search, but we’re not looking for human scientists out there.
Grab Bag Thoughts:
- Now, of course, we know of thousands of exoplanets, but I appreciate the careful skepticism with which the idea was treated back before we had the instruments and evidence that we have today. Also, it’s amazing to me that the smallest extrasolar objects we’d detected at the time were apparently 10X Jupiter’s mass.
- Neither of Drake’s “two helpful points” (a 5 billion year constraint, and a “ecosphere”/habitable zone/liquid water argument) are bad starting places – after all, we only have one data point to go off of. They do, however, seem anthropocentric (or maybe just simplistic) in hindsight. Then again, I suppose I have to keep in mind that the ideas and the search itself were novel at the time – hence the reason this was assigned!
- On first read, the idea of a “group of intercommunicating civilizations” seemed a little far-fetched to me – we know nothing about the politics/society/mindsets of potential civilizations, so imagining a ton of independently arising civilizations that are all curious, cheery, and helpful seems a little optimistic. It was interesting how prevalent this idea seemed to be (Cocconi and Morrison imagined that they “look forward patiently to answering signals from the Sun” and Bracewell thought they were “probably already linked together into an existing galaxy-wide chain of communication”). But once I’d read Sagan’s argument from Sagan and Newman 1982 (I’ll talk about it in more depth in a future post), I could see the first justification for the popularity of this idea; in a nutshell, civilizations will be subject to a Darwinian evolution that will only preserve those that are not aggressive and intent upon colonization. Comprehensive explanation? Maybe not. But food for thought.
- In light of some of the later papers in the semester, Drake’s rigorous scientific search for intelligent/sentient/communicative life seems very grounded and so much better than the general state of the literature in the decades to come. Is it coincidence that passions seemed to get inflamed about the subject in those following decades during funding struggles (a la Garber 1999) and after those original, perhaps a little too airy, early papers? Searching for sentient life has so many benefits that searching for non-sentient life does not (in the form of unintentional or intentional technosignatures) and I wish we had more evidence yay or nay in the form of searches like this one.
~ Less Relevant Coda – How Poorly Things Age ~
Much of what caught my eye while reading this paper wasn’t directly related to the scientific content but rather some (now) obvious faux pas.
- Citations! Where are the citations?! It took me forever to figure out who Calvin was and what he did! Answer: if he was Dr. Melvin Calvin (my best guess) he was part of the Berkeley physics department back in the 1960s (go bears), Director of the Laboratory of Chemical Biodynamics at LBL, and won the 1961 Nobel Prize for Chemistry (according to the LBL website)
- The “Harpsichord Maker with a Ph.D. in Physics” job posting is just a goldmine. Prize goes to “Men with appropriate advance degrees, preferably a Ph.D., are invited to…”. Intellectually, I know that’s just how it was back then, but it’s startling to read it now.