It’s the controversy that launched a thousand X posts. 

Elon Musk, who is a fan of Homer, has kicked up a fuss by objecting to filmmaker Christopher Nolan casting the black actress Lupita Nyong’o as Helen of Troy in his forthcoming movie version of “The Odyssey.”

The epic production presumably won’t rise or fall based on its depiction of Helen, the legendary beauty who precipitated the Trojan War.

That conflict, after all, is portrayed in “The Iliad” — while “The Odyssey” follows the Greek warrior Odysseus on his return home after the war, a story that doesn’t feature Helen prominently. 

The casting of Nyong’o, though, has raised the perennial question of what Helen looked like, as well as the more pedestrian matter of what the standard should be for actors playing people of a different race or ethnicity (or, these days, gender). 

Helen was a Spartan woman, married to Menelaus, the King of Sparta.

When she left him for Paris of Troy, it started the long battle between the Greeks and Trojans.

Everyone who saw her instantly understood why a years-long war over her was worth it: “No wonder the Trojans and well-greaved Achaeans have suffered long for such a woman — she is terribly like an immortal goddess to look at.”

The genius of Homer’s description of Helen is that he leaves it vague, and therefore up to the imagination.

We know, though, that she wasn’t black. 

The co-host of The View, Sunny Hostin, slammed all the critics of the choice of Nyong’o as ignoramuses for not realizing that Africa was supposedly the source of Ancient Greece.

In so doing, she relied on a discredited book called “Black Athena,” which maintained that ancient Sparta and Phoenicia colonized Ancient Greece.

There is no evidence for this whatsoever: One scholarly critic compared the book’s highly politicized claims to “the Aryan science of the Third Reich or the Lysenkoite genetics of Stalinist Russia.”

Ancient Greece was Indo-European in origin; the people who lived in the area back then looked, by and large, like the people who live there now.

Homer says that Helen was “white-armed,” suggesting that she was fair-skinned.

Other ancient sources can be interpreted as saying that she had light hair and blue eyes, although there’s debate about this. 

Certainly, depictions on film have favored this interpretation: The 2004 movie “Troy” cast the gorgeous blonde-haired, blue-eyed German actress Diane Kruger as Helen. 

All that said, what the role most requires is luminous beauty — and there’s nothing inherently wrong with casting actors in roles that don’t match their ethnicity.

Macbeth wasn’t African American, but Denzel Washington played him compellingly in a movie version. 

The problem is that such casting decisions can be distracting, or even parodic.

The Churchill movie “Darkest Hour” had the wartime prime minister taking a random trip on the London Underground and getting a pep talk from a black laborer.

Why insult everyone’s intelligence with this kind of pandering? 

And there should be a uniform standard.

Whenever a white actor or actress is cast in a role of another ethnicity it’s condemned as “whitewashing.”

A furor ensued when Scarlett Johansson played Motoko Kusanagi in the movie version of the Japanese manga series “Ghost in the Shell” — even though the character is a cyborg.

Johansson had to back out of another project when she, a cisgender woman, was cast as a transgender man. 

A headline in Allure magazine at the time read, “Scarlett Johansson Is Facing Major Backlash for Saying She ‘Should Be Allowed to Play’ Anyone.”

What’s good for Lupita Nyong’o should be good for Scarlett Johansson, and vice versa.

But Hollywood wants to put its finger on the scale.

It maintains preposterous, bean-counting standards for what films can be considered for Oscars based on the inclusion of “underrepresented groups” on screen and behind the scenes. 

If Nolan has done his job, this “Odyssey” controversy will be overwhelmed by the power of Homer’s work — perhaps the second greatest story ever told.

X: @RichLowry