KSJ Tracker October 1, 2013

Harvard, MIT scientists invent a lightsaber! Or do they?

"Star Wars lightsabers finally invented," screams the headline on a story in theguardian.com by Ben Child.

Pretty cool, right? Looking for elaboration and further excitement in the lede, we find "Wannabe Jedi Knights rejoice," because scientists "have discovered that the famous lightsaber weapon wielded by Luke Skywalker and his ilk in the long-running space opera saga might one day exist beyond the realms of fiction."

What alchemy transformed "might one day exist" in the lede into "lightsabers finally invented" in the hedline?

Well, never mind about that. What exactly did the scientists do? Child quotes Harvard physicist Mikhail Lukin, who says, "What we have done is create a special type of medium in which photons interact with each other so strongly that they act as though they have mass, and bind together to form molecules."

And there you have it: A lightsaber!

I confess: I didn't get it either. But, thankfully, we have further explanation from Lukin: "It's not an in-apt analogy to compare this to lightsabers. When these photons interact with each other, they're pushing against and deflect each other. The physics of what's happening in these molecules is similar to what we see in the movies."

Lukin's boisterous photons can't be like the physics we see in the movies, because there is no physics in the movies. They're movies.

Danielle Elliot at CBS News says the moment for lightsabers "might finally be here." Or it might not. She, too, is  having trouble deciding whether they've been invented yet.

Elliot reports that "the principle of the Rydberg blockade" causes photons to clump together. Which means, I guess, that he could construct a baseball bat out of photons, which he hasn't yet done, and likely will never do, because the wooden ones work so well.

But lightsabers are quite a bit more sophisticated than baseball bats, aren't they? A baseball bat can't zap a training remote or cut somebody's hand off. Also, Elliot reports that this works only in a special medium: Before you could use your lightsaber on an adversary, you'd first have to lure him into a cloud of cooled rubidium atoms.

An unbylined story at FOX NEWS quotes MIT physicist Vladan Vuletic, Lukin's colleague, who told WBZ-TV that "maybe a characteristic of a lightsaber is that you have these two light beams and they don't go through each other as you might expect; they just kind of bounce off each other."

Yeah. Maybe.

Most other stories I saw grappled with the momentous question of whether lightsabers had been invented or just foreshadowed. But all bought the line. Lightsabers were/will be/could be/have sort of been invented by physicists from Harvard and MIT.

Then I found the headline I think I was looking for all along. "Relax," it began, and I did, almost immediately.

"Relax, MIT and Harvard Scientists Did Not Build a Lightsaber," read the hed on Glen Tickle's story on geekosystem.com

"Pump the brakes, everyone," he writes. "They have not created a lightsaber." They've discovered molecules that might have important implications for quantum computing. Tickle, unlike so many others, finally puts us on solid footing.

The comparison to a lightsaber was part of a Harvard University press release. I'm not against having a little fun, but the discovery here was finding a way to get two photons to bind to one another in very exotic circumstances. The press release says these bound pairs of photons "behave less like traditional lasers and more like something you might find in science fiction – the light saber."

They don't behave anything like a lightsaber. The phony comparison got Harvard a good ride on its press release, but most of the stories told readers little if anything about what the scientists had done. There might be a good story on quantum computing here, but we'll never find it amid the shattered remnants of battle-worn lightsabers.

When exoplanet hunters said they had found a planet orbiting two stars that resembles Luke Skywalker's home planet of Tatooine, it was not an "in-apt" analogy, to use Lukin's word.

That's not true of the lightsaber analogy. It is "in-apt." (And there is no hyphen in inapt.)

-Paul Raeburn


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