Great description of ISBN format description and visualization. TIL that 978- prefix was “Bookland” ie a fictional country prefix that may be thought of as “Earth”. It has expanded to 979- which was originally “Musicland”.
This probably means that in the (hopefully near) future where we have extraterrestrial publishing (most likely in the Moon or Mars) we’ll need another prefix.
Not really. The 978 prefix, or previously ISBN-10 namespace, in addition to a recalculation of the checksum, makes most books go into the EAN-13 namespace. EAN is meant for unique identifiers (“Numbers”) of “Articles” in “Europe”. Later that got changed to “International”, but most still prefer the acronym EAN.
So 978 really is Bookland, as it used to be, and Earth, but the EAN-13 namespace as a whole really does refer to Earth as well. That said, the extraterrestrials can get a prefix just the same?
This probably means that in the (hopefully near) future where we have extraterrestrial publishing (most likely in the Moon or Mars) we’ll need another prefix.