This story made for a fantastic (albeit slightly out of order) finale to my experience in this SETI class. Several different story lines are captured within this one brief encounter described in the story. I also love the first line – “the best is the enemy of the good” – and firmly believe that this is an important philosophy to keep in mind while doing science.
Beyond being an extremely entertaining story, the article touches on a fundamental theme of SETI: what seems obvious to us may not be universally so, and, no matter how we try, we are unable to decouple our thoughts and ideas from the human perspective. Try as we might to search for “obvious” signals of extraterrestrial origin, it is entirely possible that some extraterrestrial intelligence is, in their own way, screaming their greetings to us and we are simply blind to the significance of the signal.
Townes raises the question of where in the electromagnetic spectrum should the search for extraterrestrial intelligence be conducted? While SETI has historically been radio-centric (especially at the time this paper was published), the author suggests that certain assumptions are required to arrive at the conclusion of the radio as the optimal region to search. If these assumptions are appropriately relaxed, one could argue that the infrared is an equally viable part of the spectrum to search for signals of extraterrestrial origin.
One aspect that must be considered in choosing the optimal spectral region is the power requirements of the transmission. This depends on whether the signal is isotropic or beamed, which, of course, we can only guess. A second point that must be considered is the technology of the transmitter and, more broadly, the technology of the transmitting civilization as a whole. In particular, it is conceivable that other forms of communication technology could be dominate on a distant world, e.g., lasers. This relates directly to the suggestion by Schwartz & Townes (1961) to search for nanosecond light pulses in the optical.
Ultimately, the authors recognize that the optimal SETI search would be include efforts across the electromagnetic spectrum. After all, arguing for one particular spectral region over another involves making a set of assumptions that could turn out to be false.
The International Academy of Astronautics (IAA) compile a set of principles to guide the Search for Extraterrestrial Intelligence (SETI). SETI inherently concerns the entire world, especially in the case of a positive detection, so extensive thought must be lent to ensuring SETI efforts are conducted in an ethical and scientifically collaborative manner.
In many ways, though, this document appears to raise more questions than it answers. For example, the last point regarding post-detection conduct could (and should!) trigger a storm of debate, garnering expert advice in fields such as communications, law, ethics, and anthropology (among many others.) While it is important that these guidelines have been put in place by the IAA, it is equally important to establish some sort of platform for discussing the questions raised by these guidelines.