I realize you can just answer, "mysterious aliens beyond our understanding," but why would a space probe have a mandate of either talk to a whale for 30 seconds or destroy Earth and disable everything in its path on the way to Earth?
We don’t know. That’s part of the mystery of the movie. We don’t even know if the probe was intentionally destroying things. If you can’t vibe with the mystery and go along for the ride, then it’s not for you. Nothing’s for everyone.
These were beings who were casually chatting, non-technologically (at least on the whales end), over hundreds of light years. Their tech is completely unlike anything The Federation has ever seen, or even imagined within its understanding of physics. Whatever it is is incompatible with earth-like worlds and anything they make, but we needn't think it necessarily malicious.
Imagine if tube worms from a deep sea volcanic vent sent a probe to check in with a major city. Their probe would likely be toxic to anyone downwind because of all the sulphuric chemicals and heavy metals, it may set everything around it on fire if it maintains its home temps, and would likely be giving off radon in a way that would shorten neaby lives. It's not intentional, its just their natural state.
What good did the last russian lunar probe do when it cratered into the surface a few months back?
If the builders didn't know it would do that and weren't in real-time control then it may have just been an oopsie-daisy. They're contact with us has been via an IRC chatroom, hanging out with with a bunch of flipper dogs. How were they supposed to know?
I believe the probe was not destroying anything intentionally, but this was rather a side effect of whatever it was doing to attempt to communicate with the not-the-hell-your-whales. Once it did so and was satisfied it shut off its transmitter and went about its merry way.
I don't know why it specifically needed whales. Maybe some other similarly whale-like alien species would also have sufficed.
I'm pretty sure Spock actually said this and this is the way I always understood it. Spock went on a hunch that it wasn't intentionally destroying the planet, it was a byproduct of looking for the whales. Maybe it had to look harder than expected and turned up the transmit power which is why things got weird.
Second edit: I just saw a thread the other day about the weakest sonar pings from Navey subs being strong enough to vaporize people's insides. Context I guess.
I think the long and the short of it was that the writers and Leonard Nimoy were going to drive home An Aesop about environmentalism, no matter what it took.
There is also some parallelism here with the real world in addition to your sonar ping observation. For instance, I always recommend anyone to read "Last Chance to See," by Douglas Adams (yes, that Douglas Adams) and in this case the chapter on the Yangtze river dolphin wherein Adams and his crew (or rather, the crew with Adams tagging along) go to China to observe said creature. The Yangtze river dolphin was -- it is now believed to be extinct, but was not at the time the book was written -- functionally blind and relied on echolocation to navigate and, you know, not bump into things. Just through the course of normal river navigation there is so much noise in the Yangtze from engines and boat propellers that the dolphins were just about deafened as well as blind, which was probably a contributory factor to their extinction.
Humans didn't set about to blast the dolphins clean out of the water via noise pollution on purpose, but nevertheless that's exactly what we did just as a result of how our vehicles worked and without thinking about it.
One hell of a side effect. You'd think its creators would understand the whole 'destroy the planet' aspect of their 'must communicate with a whale for a very brief period of time unless there aren't any and then I just stick around' plan.
It's been a minute for me - did they ever establish that it absolutely had to be whales or were whales just sea creatures that qualified?
What if this thing was sent to harvest water from planets lacking intelligent cetaecian life forms like humans might harvest a resource from an "uninhabited" world?
You're out in your backyard playing with your dog. You're both running around in the grass, rolling around, the dog digs for a moment at a spot in the yard. You think nothing of it.
But in those few minutes, you both stomped on and destroyed a couple ant mounds, squashed some other bugs and insects in the grass (their habitat) and the dog dug up and obliterated another creatures nest in the grass.
In Star Trek, some cetaceans are sentient. They may have had first contact with others long before humans and forged some kind of relationship with the alien entity(s). The probe was coming to either check up and make sure their friends still exist, or avenge their extinction (I'm sure if they were in touch, they were telling them all about the atrocities we were inflicting on their species.). It came ready to wipe us out, and contact with an actual whale changed its mind. The whales may have told it to back down as well, after they had their mind meld conversations with Spock and decided to help when he may have told them that humans of the future had completely changed their ways.
Bc the mice that ran the universe in order to find the question that answered everything decided to call in someone to check in on their friends the dolphins, and the whales... never mind, I've said too much already!🤪
Back in the 80s everyone thought that whale was going to be the hottest new actor in Hollywood. They were all trying to sign him, for a second it was thought he would be playing opposite Tom Cruise in Top Gun.
I don’t have much to add myself except for the beta canon book ‘Probe’ that delves into a lot of the background and even mentions the Borg in a roundabout way.
They may not be explaining things very well on that page but this basically ignores half of what the probe did in the movie and why it needed 30 seconds to talk to a whale.
spoiler
Spock successfully mind melds with the probe, learning that it did not seek to be destructive to other races, instead they were so different from its creators that they were ignored as "mites" in "metal bubbles",
Which is more improbable: that, or there being no hallucinogenic drugs in Kirk and Spock's time?
If they can easily manipulate molecules to make sheets of materials like transparent aluminum, AND they seem to keep an illegal stash of Romulan Pale Ale, imagine the mind-bending mind-enhancing substances they can come up with four centuries from now, yet square-jawed Kirk seems completely oblivious to the whole concept.
Swearing they're aware of, but it's more of correct colloquial context for the time. It'd be like me going back 40 years and calling someone a fucktard.
If you're referring to the LDS flub, that could really be easily handwaved away as it was a drug that just fell so far out of fashion and use it's barely a foot note in history books. Enough for Kirk to be aware of its history yet to not remember the correct name.
By his point in time humanity has chosen to expand their minds with knowledge and exploration...and lots of booze
It probably should've been dolphins, just as a nod to H²G², but also because I'm not sure the scale of that Klingon BOP ever read as big enough for two whales to me.
But, some possible suspects: whales (maybe they are superintelligent, pan-dimensional beings and the business with the krill and the singing is just a front), whale keepers or collectors (maybe they've stocked Earth with an important livestock that they want to protect from the apes, or see TNG S3E22 "The Most Toys"), whale descendants (see VOY S3E23 "Distant Origins"), or a species that has determined that loss of the whales indicates humanity has become irredeemable (or a corrupted timeline).
I know this movie is a subculture favorite (my personal theory is because of the popularity of who directed it), but except for some funny moments it's one of my least favorite; not least for how much it has to lean on inexplicable plot devices. At least in ST:TMP, Vger had a motivation for blowing things up and being petulant: it clearly had its own understandable desires.
I have warmed up to it over the years, but I admit I have always thought of it more as "Comedy Star Trek" than "Star Trek with Comedy." But now we have Lower Decks, so...