Sciency Words: (proper noun) a special series here on Planet Pailly focusing on the definitions and etymologies of science or science-related terms.  Today’s Sciency Word is:

DIAL TONE

Some of you may be too young to know what a dial tone is, so here’s an instructional video explaining the concept.

According to this article from Teletech Services, it was German engineer August Kruckow who invented the dial tone back in 1908.  A dial tone is a buzzing or humming sound that landline telephones make to let you know they’re connected and working.

It’s hard to say when “dial tone” became a SETI term, but the earliest usage I was able to find is this 1995 paper by Steven Dick entitled “Consequences of Success in SETI: Lessons from the History of Science.”

In that paper, Dick draws a distinction between extraterrestrial signals that communicate information vs. extraterrestrial signals that serve essentially the same function as a dial tone.  The general public, Dick argues, would react quite differently if we picked up some sort of intergalactic dial tone instead of a “Greetings, Earthlings, would you like to learn more about calculus?” type of message.

Later papers (like this one or this one) continue to use this dial tone metaphor, and in 2018 a special committee on SETI nomenclature adopted the following as the official definition for the term: “A content-free beacon, i.e. one that communicates only the existence of technological life.”

That same committee goes on to note some concern that the conventional meaning of “dial tone” may soon become obsolete; if so, the committee worries, then the continued use of “dial tone” as a SETI term might become problematic.  I’m not sure I agree with that concern, though.  Lots of terms and phrases have stuck around even after their original meanings have faded into history.

In the near future, maybe it won’t be obvious to everyone that “dial tone” originally had something to do with telephones, but if SETI scientists keep using the term, I don’t think it’s that hard for people to understand what the term means… is it?