

More often than not, when you see a headline proclaiming the invention of an invisibility cloak, it’s all just smoke and mirrors. A recent experiment reported in the journal Science isn’t necessarily the magical cloaking device humanity has been dreaming about for generations, but it’s much closer to reality than previous attempts. While still a laboratory proof of concept, this new experiment uses common, off-the-shelf materials and easier-to-reproduce conditions to create the most reliable cloaking effect yet seen.

What is unique here, is that the materials and conditions at work are not anything terribly special; most scientific facilities around the world can build the cloak without any expensive exotic materials. Additionally, many experiments that purport to demonstrate cloaking effects are done in strenuously controlled laboratory conditions on a microscopic scale. Researchers in this case needed only a superconducting tube 12.5mm long, low temperatures, and a stable magnetic field.

In the experiment, the tube in question with its inside surface coated in a superconducting tape and its outside made of a magnetic alloy, was cooled to 77 degrees above absolute zero; that’s 77 Kelvin for the scientifically inclined, or -196C. When a magnetic field was applied to the tube, the magnetically active outer layer attracted the field, but at the same time the superconductive inner layer repelled it. The result is that the magnetic field is kept entirely uniform at both ends of the tube. That is, the tube and anything inside it are magnetically cloaked from an outside observer.

Magnetic cloaking

What was accomplished in this experiment is not what we think of as “Star Trek” cloaking because it was only manipulating a magnetic field. Visible light is a small part of the electromagnetic spectrum, but the principal could be essentially the same. A cloaking device would simply have to make the electromagnetic profile in front of you look the same as behind you. Do that, and you’re invisible. Of course, that also means you wouldn’t be able to see out of the cloak, but science can cross that bridge when we come to it.

When you look at how far we still have to go, it might seem like we’ll never see that seemingly magical device that makes things invisible with the flip of a switch. Though, this experiment is a real step forward in that respect. Previous efforts required researchers to maintain conditions much closer to absolute zero, for example. It is believed that the same principles at work in this experiment could, someday, be used to manipulate an electromagnetic field like visible light in the same way at room temperature.

This scenario is still not entirely realistic or ready for any kind of general deployment. The magnetic field used was kept uniform in order for researchers to discern the effects, but there are definitely applications in laboratory conditions for this magnetic cloak. You’re not going to be the invisible man any time soon, but this is still an interesting new method that could be improved on in the future thanks to some killer science.

Read more at Science (paywalled)