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Quantum Levitation: The Coolest Science You'll See Today

| 18 Oct 2011 21:22

The video you are about to see contains high-level physics, quantum superconductors and presumably wizards. You have been warned.

The clip, which has been making its way around the 'net since its debut this weekend, was taken at the 2011 ASTC conference, a gathering of sciencefolk in Baltimore, Maryland designed to demonstrate "how science centers and museums are putting new ideas to practical use to serve their communities."

This vignette is a demonstration by Israel's Tel Aviv University of a phenomenon called "quantum levitation." Though the video itself fails to explain the physics behind the disk's baffling ability to maintain orientation despite non-trivial factors like gravity and the rampant disbelief of onlookers, the University put together a website to explain things.

If I'm understanding this correctly, the disk (which is a sapphire wafer coated with an ultrathin layer of yttrium barium copper oxide) is cooled to below negative 185 degrees Celsius. At that temperature the material becomes superconductive (read: it is able to conduct electricity with no energy loss).

From here on out things get a bit complicated, so I'll just quote the site's surprisingly excellent explanation:

Superconductivity and magnetic field do not like each other. When possible, the superconductor will expel all the magnetic field from inside. This is the Meissner effect. In our case, since the superconductor is extremely thin, the magnetic field DOES penetrates. However, it does that in discrete quantities (this is quantum physics after all! ) called flux tubes.

Inside each magnetic flux tube superconductivity is locally destroyed. The superconductor will try to keep the magnetic tubes pinned in weak areas (e.g. grain boundaries). Any spatial movement of the superconductor will cause the flux tubes to move. In order to prevent that the superconductor remains "trapped" in midair.

Science fiction author Arthur C. Clarke once wrote that "any sufficiently advanced technology is indistinguishable from magic." Though at the time he was referring to theoretical technology found in his stories (and using this explanation as a reason why he had no need to explain the inner workings of his fantastical creations) it seems tailor-made for this situation.

Even with the physics explained to me I'm tempted to throw holy water at my screen. Either that or start a cult to worship that disk. "Ad majorem orbis gloriam," the chants will say, and then we'll hear a reading from the Book Of Disk, specifically, Disk's First Letter to the Corinthians.

"When I was a disk, I spoke as a disk, I felt as a disk, I thought as a disk," and so on and so on until we get bored and find another inanimate object to worship.

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