Or, more precisely, a way of geoforming the ocean floor to almost eliminate surface waves.

Sessions at the 65th annual meeting of the American Physical Society’s division of fluid dynamics  include presumably fascinating talks on “Bubbles,” “Vortex,” “General Fluids,” and “Drops.” Not to mention “Bubbles II.”

One paper being presented, however, has a less pedestrian title: “A Cloak of Invisibility Against Ocean Waves.” Reza Alam, a professor of mechanical engineering at the University of California, Berkeley, will be speaking about a way he has discovered of neutralizing ocean waves in near-shore or off-shore areas.

How?

The magic — or the science — lies in the fact that, as Alam explained to Phys.org, the ocean is stratified into layers: warmer, less dense water at the top, and colder, heavier water at the bottom. Each layer has waves: surface waves at the top, and internal waves in the lower levels. And, crucially, all waves — even surface waves — interact with the ocean floor.

By “properly architecting the bottom corrugations” of the ocean floor, Alam has discovered that “floating objects in stratified fluids can be cloaked against broadband incident waves.” Translation: by making the right hills and valleys in the ocean floor, waves can be transformed from surface waves to internal waves.

Meaning that, from the perspective of an observer floating on the surface of the ocean, the waves have simply disappeared. Of course, they actually have not — they have simply become internal waves deeper within the ocean layers.

And a reverse effect is possible as well. As Alam told Phys.org, “In reverse, it can cause the … reappearance of surface waves in areas where sandbars or any other appreciable bottom variations exist.”

Which means that the same technology that might help shelter marinas or offshore installations might also be used to create a surfer’s paradise.

photo credit: nathangibbs via photopin cc, play4smee via photopin cc

Scientists at the Pentagon have just published some fascinating (understatement) research on “temporal cloaking”.

As the team noted in Nature,

“To achieve spatial cloaking, the index of refraction is manipulated to flow light from a probe around an object in such a way that a ‘hole’ in space is created, and the object remains hidden. Alternatively, it may be desirable to cloak the occurrence of an event over a finite time period, and the idea of temporal cloaking has been proposed in which the dispersion of the material is manipulated in time, producing a ‘time hole’ in the probe beam to hide the occurrence of the event from the observer.”

Translated into lay-nerd terms, these scientists figured that light allows us to see objects, so to make an object or event invisible, all you have to do is keep the light from hitting it (a key component of other existing invisibility technology). And to keep it invisible for a period of time, you have to speed up the front end of a beam of light while slowing down the back end, creating a gap.

And these blessed souls have found a way to do precisely that.

Here’s a look at how the experiments went down:

Don’t expect to see invisibility “time holes” in your corner Army Navy surplus store any time soon, though. The experiments occurred inside a fiber-optic cable over the course of a few picoseconds. Still, the team noted in its conclusions, “These results are a significant step towards the development of full spatio-temporal cloaking.”

Stay tuned for Star Trekian cloaking devices, invisibility cloaks and other optical camo coming soon-ish to a top-secret military lab near you.