I never gave this episode much though in the chronology of Star Trek, but currently I'm doing a remastered original series rewatch in production order and just watched "Miri".
In that episode Spock stated that the timeframe that everything went to hell on Earth II was equivalent to about 1960 Earth, and that 300 years had passed since then.
That would place Miri at the 2260's. Now, that is of course assuming that 1960 on Earth II happened at the same time as Earth I.
I think it's probably safe to assume that they wanted the time frame on both Earth's to match. Based on that it's probably safe to assume they wanted to place Star Trek in the 23rd century. At the time you could argue what part of the 23rd century. We now know the exact timeframe of course, but it does seem to match up with the original intent mostly.
Yeah, true. In a way this debate is pretty much meaningless these days. It's been established, on screen and in canon now by multiple sources that Star Trek took place in the late 23rd century, and now we even have canon evidence of the actual years.
From TMP to TWOK, and TNG, Voyager, Star Trek (2009), STID, Beyond, and Discovery have all established without a doubt when Star Trek takes place. And even in TVH Kirk told Gillian he came from what would be on her calendar as the late 23rd century.
It's fun to debate what the original intent was back in 1966-1969. But it's sort of a moot issue at this point. I mean, unless for some people there was no Star Trek after the animated series.
General Comments:
Once again I say that because many different dating systems and calendar eras have been used, are used, and will be used, on Earth in real life, and there is strong evidence that several different calendar eras are used to give Earth dates in different
Star Trek productions, it is impossible to tell which dates are given in which dating systems. It is a risky assumption to assume that an Earth date in
Star Trek is an
Anno Domini date if it is not specified as an
Anno Domini date.
https://en.wikipedia.org/wiki/Calendar_era
Thus it is probable that TOS happens in the 22nd century according to some of the Earth dating systems used in
Star Trek movies and episodes, and in the 23rd century according according to some of the Earth dating systems used in
Star Trek movies and episodes, and quite possibly in other centuries according to some of the Earth dating systems used in
Star Trek movies and episodes.
And it is not so certain which century AD TOS happens in, and less certain which decade and years in that century.
The key dates used in establishing the dates of various
Star Trek productions are not specified as being AD or CE (Current era or Common Era) dates, and thus the official dates of various
Star Trek productions are not canonical proof that those productions happen on those dates.
The Interpretation of "Miri":
In "Miri" they beam down to a street with 19th century urban architecture and mid 20th century automobiles:
KIRK: Identical. Earth, as it was in the early 1900s.
SPOCK: More the, er, mid-1900s I would say, Captain, approximately 1960.
RAND: But where is everybody?
SPOCK: Readings indicate that natural deterioration has been taking place on this planet for at least several centuries.
This indicates that they used
Anno Domini dating in "Miri", or at least a dating system counting years from an era close to AD 1.
Going into an abandoned building they find a piano in one room:
KIRK: How old is this thing?
SPOCK: About three hundred years.
There are several ways to interpret this:
One way would be to assume that Spock, with his vast knowledge of old Earth musical instruments, decided that the piano was of a design built about AD 1960, and then calculated the Earth years since then to say "about three hundred years". That would place "Miri" about AD 2260, give or take as many years as Spock's "about" allows.
A second way would be to assume that Spock scanned the wood in the piano and carbon dated the cutting down of its tree(s) to about 300 years ago. That would prove that the piano was made about 300 years (plus or minus an unknown number of years due to Spock's "about") before "Miri", and some short or long time after the piano was made a disaster happened, also a few centuries before "Miri". It would say nothing about the
Anno Domini date of "Miri".
A third way would be to assume that Spock decided that the thickness of the dust on top of the piano indicated that the dust had been piling up on the piano for about 300 years, and thus that the disaster had happened about 300 years ago. That would prove that 300 years ago the alien society had been about as advanced as Earth in 1960. But it would say nothing about the
Anno Domini date of "Miri".
A fourth way would be to assume that after saying:
SPOCK: Readings indicate that natural deterioration has been taking place on this planet for at least several centuries. [/QUOTE]
Spock continued to take readings, and soon narrowed down "at least several centuries" since the disaster to "about three hundred years" since the disaster. So when Kirk asked how old the piano was, Spock told him that it had been abandoned for "about three hundred years", since Spock did not know how old the piano was when abandoned or the total age of the piano.
That would prove that 300 years ago the alien society had been about as advanced as Earth in 1960. But it would say nothing about the
Anno Domini date of "Miri".
And why assume that Miri's Planet, as it is sometimes called, was about as advanced as Earth in AD 1960 when the life prolongation project resulted in a disaster? Could Earth have started such a project with mid 20th century science? If mid 20th century Earth could have started such a project, why didn't they? How many of your relatives have died in the 50 years since then whose lives might have been saved by a successful life prolongation project?
It seems possible that Miri's Planet was decades or centuries more advanced than 1960 Earth or even 2019 Earth.
The town might have been inhabited by equivalents of Amish or survivalists or simple lifers for decades or centuries until it eventually became owned by the life prolongation project which didn't bother to modernize the appearance of the buildings and continued to use the old fashioned cars.
Or possibly the town was some sort of recreation of a centuries old lifestyle, like Colonial Williamsburg, or maybe a theme park about a past society like
Westworld, which may have gone bankrupt and been bought by the life prolongation project.
Or the town could have been a place with a lot of well maintained (until the disaster) centuries old buildings. I have spent a lot of time in Cape May, New Jersey, where there are block after block of 19th century Victorian houses and buildings, covering far more ground than the outdoor set used in "Miri". And of course there are many quaint old towns and villages in Europe filled with centuries old buildings.
So possibly the life prolongation project took place in a town filled with centuries old buildings, and where the inhabitants might have used vehicles that looked like centuries like automobiles on the outside.
It is certainly possible that Miri's Planet might have been more advanced than 22nd or 23rd century Earth when the disaster struck, with the life prolongation project merely being located in a very old looking community.
The society on Miri's Planet could have been advanced enough for interstellar travel:
KIRK: Earth-style distress signal. SOS.
FARRELL: I've answered it on all frequencies, sir. They don't reply.
SPOCK: Not a vessel, a ground source. The third planet in this solar system, according to my instruments.
FARRELL: Directly ahead. Definitely an Earth-style signal.
And:
KIRK: We'll beam down. Alert security. Prepare to transport landing party to surface. We'll land in the vicinity of the distress signals now being received.
So they didn't beam down to a random location on the planet, but to the town where the distress signal was being sent from.
And:
KIRK: There must be records somewhere and answers to some of our questions. Miri, do you know any buildings where the doctors used to work?
MIRI: Yes, I know that. Them and their pills and things.
KIRK: Will you take me there?
MIRI: That's a bad place.
KIRK: It's important. Please.
MIRI: All right. Do you have a name, too?
And:
Captain's Log, stardate 2713.6. The building Miri led us to also housed an automatic transmission station, which sent out the signal that drew us to this planet. We also discovered something else. That the blues blotches, characteristic of the unknown disease had appeared on each of us, with the exception of Mister Spock. There was a well-equipped laboratory in the building. Doctor McCoy took tissue samples of each of us in an attempt to isolate the organism responsible.
So the rather small laboratory in the town, the laboratory where the life prolongation project worked, also housed the only transmitter on the planet that sent a distress signal during the disaster.
That indicates that the town they beamed down to might have been the largest or only settlement on the planet, which might have been colonized by another planet, probably in another star system. The entire colony might have been established to work on the life prolongation project.
And possibly it was fashionable at that time to build buildings and use vehicles that looked very old fashioned, like mid 20th century Earth.
If that is the case, it would be uncertain whether the other planet(s) of their civilization quarantined Miri's Planet to avoid the plague, or if they sent assistance and the plague spread back to those other planets.