Those dates.. in '72 and ~Launch date of Voyager via usual 20/20 hindsight: mesh with a number of events as would be utterly-TMI (to moi) ... even to limn.

Overall, in That choice of a "medium" for transmission to the Unknown/Unknowable of what.. a few pretty-smart Homo-saps deem ..well,
All and Everything! which homo-sap deems Most Significant about Us + our Tenure on--an increasingly-embattled, once Shining natural Jewel of--a PLANET

... well, por moi the Choice was 'fascinating' while also being hilarious in this sense:

Starting from Edison's wax-cylinders ---> Onward, I cannot think of a comparable situation to the unending-Search for "near-perfect capturing-thence-re-playing" of AUDIO [!!]
Never mind 'scientific method' as some Sole arbiter of that 'Perfection', given the emotional qualities of any {at-all-memorable} opus eliding the ludicrous-pricing bizness-du-jour
of [n+] gadgets competing for individual Champion of Ludicrosity (?? er, Shirley that' IS their game.)

Ergo: {chortle} NOW-as-of-1977 "We" have sent out to the Cosmos ... a 33 1/3? 16 2/3? RPM pair of vinyl-in-Gold L.P.s

---

Let's imagine Aliens 1, 2, 3 ...n ... Whenever ... Wherever ...

HOW!ever: goin through
the perpetually-unFinished
Terran search for - - - - ->
The. Best. Playback.
(maybe in Hilbert Space? by-any-Alien-sobriquet.)

Love. It. ;^>

(Y'all'd have to have been a 'Audio Conslutant' for a period, to grok-to-Fullness.)