# Beyond the beam of light...

A beam of light, passing the boundary of two media, is usually split into two rays - reflected and refracted. An elegant regularity was also known to the ancient Greek scientist Ptolemy: the sine of the angle of refraction is many times greater than the sine of the angle of incidence, the number of times the refractive index of the first medium is greater than the refractive index of the second (we are now discussing the transition of light from a denser medium to a less dense medium). Changing the angle of incidence, we can make it straight, the sine of which is equal to one. So, the sine of the angle of refraction will be so many times greater than one. Wait a minute! The sine of the angle of refraction will exceed unity? Absurd! No, unit is the limit of growth and this sinus. In this limiting case, the refraction angle becomes 900, and the refracted ray spreads along the media interface. And if we continue to increase the angle of incidence of the light beam, it will simply stop refracting and will undergo the so-called "total internal reflection". So it was considered a long time. Here you and the physicists have a kind of boundary: while the angle of incidence is small - the ray is reflected and refracted; the angle of incidence has exceeded a certain value-the ray is only reflected. But does the refracted ray disappear without a trace?

Careful experiments showed: a ray of light penetrates the "absolutely reflecting boundary", but not in the form of a conventional ray, but in the form of a special electromagnetic wave that strongly decays when moving away from the interface that carries energy back and forth on either side of it. And this wave can again turn into visible light, if it again falls into a denser environment.

So scientists managed to look abroad, at first it seemed insurmountable. And so always, as soon as the physical theory delineates any limits, in someone's inquisitive mind the question arises: what is there, beyond this boundary? Here are just some of these questions that await an answer.

The speed of the light beam is the natural limit of all velocities observed in nature. What is beyond this boundary?

At a temperature of -2730 C, the motion of atoms and molecules freezes - not without reason this temperature is called absolute zero. Is it possible to overcome this boundary?

All bodies are attracted to each other. But can not the gravitational force be reduced to zero and then break this zero mark, make the bodies repel?

Time always flows in one direction - the past, as they say, you can not return. Can you stop his running, make him run backwards?

These questions may seem to be the fruit of a baseless fantasy, and yet the thought of researchers often comes back to them.