Carbon nanotubes are at last doing something cool. Scientists have figured out how to use the "mirage effect" to completely make an object disappear. The effect uses the tubes and it only works underwater.

Finally! An invisibility cloak! That Aquaman can use. Scientists at the University of Dallas have figured out how to make objects disappear utterly underwater, using little more than some carbon nanotubes and generous heating. Carbon nanotubes are one-molecule-thick sheets of carbon that are looped into tubes. They have the density of air, but the strength of steel. Although they have applications from space elevators to medical nanotechnology, their more extraordinary uses have never come to fruition, and recently they've been eclipsed by graphene.

Now, though, carbon nanotubes team up with physics to make something completely disappear. And when I say, 'disappear,' I mean disappear like it has information on the Russian government.

Mirages happen because light changes direction as it passes through media with different density. The most common mirage for anyone to see is shimmering 'puddles' on a road on a very hot day. The air near the ground, warmed by the heat radiating off the road surface, is a lot hotter than the air above it. This makes it less dense than the air above it. When air changes temperature, it also changes density. As light rays head down from the sky to the ground, they're bent by the increasingly hot air, and zoom back up again without actually coming into contact with the ground. Some of these bounced light rays end up in the eyes of the viewers. They're seeing the photons that came from the sky, but since no one is used to seeing displaced sky hovering above a road, people interpret what they're seeing as the sky reflected in puddles of water on the road.

Since carbon nanotubes can be heated, and can heat the water around it, it can bend light the same way a temperature gradient in air does. Carbon nanotubes are perfect for this. They're lightweight, thin, can be transparent, and heat so quickly that the overall invisibility cloak can be turned on and off with the flick of a switch.

Via IOP Science.