I’ve been advising a team of researchers doing some splendid – and highly courageous – work capturing UFO’s almost nightly. Without identifying the team (yet), I’ll be mentioning some observations for others who are interested in doing their own research, as some study of what is going on can mark an important contribution to the community of researchers everywhere.
One set of observations concerns the disappearance of an object from direct view – we have seen many craft simply “pop out” of the sky, as if their lights went out, so to speak. This has, over several years, led to much speculation, but precious little knowledge to help define exactly what these objects are doing. However, the team I have been advising has taken a slightly different strategy here: they point both a visible light camera at a craft, and simultaneously aim an infrared camera at it. What seems to be happening is that the craft don’t really disappear, they merely stop transmitting or reflecting on the visible light spectrum that humans can see, because in the infrared, we can see that the craft remains where it is. This leads us to the question of how an object can shift its transmission or reflection of photon of radiation from one frequency register, namely the visible light spectrum, to a different one.
To make an object no longer reflect light in the visible spectrum, it would need to absorb all visible light or transmit it through the object. With our current understanding of physics, this light refraction can potentially be performed through one of three methods:
- The “stealth” mode, which involves coating the object with a material that absorbs all visible light.This can be achieved by coating the object with a material that has a high absorption coefficient in the visible spectrum, such as carbon black. More popular than this kind of material is “radar absorbing paint,” which works under the same principle and can even be purchased commercially, if you’re interested in avoiding law enforcement speed tracking.
- The “high refraction” strategy would involve the creation of a surface that has a high refractive index. Such a surface can bend the light so that it is transmitted through the object. This can be achieved by coating the object with a material with a high refractive index, such as diamond or sapphire. The higher the number on the index, the slower light travels through the medium, the more the light is bent, and ultimately – the more efficient the refraction is. Refraction, after all, means bending around. Sometimes, a single object can have various refractive indices, such as a rainbow, in which water particles are refracting light across a range of the visible light spectrum, and thus organized, the light is concentrated by (what we see as) colors in specific regions around the water particle.
- The “dispersion” approach calls for a cover surface with a structured pattern that scatters the light away from the visible spectrum. This structured pattern would need to be smaller than the wavelength of visible light, and the surface structure can be designed in such a way that the light is scattered off a radiative frequency within the visible spectrum. This isn’t impossible. For example, a moth’s eye has a structured surface that scatters light, which makes the moth’s eyes less reflective. One website describes it best:
Basically, the moth’s compound eye has textured patterns that are made up of tiny posts, each one smaller than the wavelength of light. When light hits their eyes, much of it is absorbed and passes into its cornea without disruption or reflection. The moth’s eye evolved in this way so that it could see better at night, and so that its eyes wouldn’t glimmer and attract predators.
And thus a UFO would need an outer covering full of tiny, clumped-together rods: 
(Photo Credit)
Still, this does nothing for producing light from behind the object for a viewer, so while it can make an object less reflective, it doesn’t produce invisibility as such, unless the background is pitch black.
There are several considerations here. Concerning stealth paint, we should note that any material that absorbs all visible light appears black. The craft we (and many others) have witnessed “disappearing” do not leave a black space or mask where their outline used to be. As the background sky is completely visible, this strategy doesn’t seem the likely process to explain how the craft are becoming invisible.
In summary, an object can shift its radiation so that it no longer reflects light in the visible spectrum by either absorbing all visible light, scattering the light away from the visible spectrum, or transmitting the light through the object by creating a surface with a high refractive index. With UFO observations, we see that the object are still there, as confirmed by their lingering infrared signatures. What we don’t know is how they are able to refract light in what is apparently a full 360 degree manner. But at least we have confirmed that they are playing with light.