The concept of emptiness at all the seeming simplicity is very difficult and multiple-valued. The answer to a question that there is an emptiness, is defined by that context in which it is put.
At first sight, everything is simple: the emptiness is a total absence … what? For example, if in a coffee can there was no more coffee, say that bank it is empty. But it not so: bank it is filled with air. The bank can close hermetically and to extort from it air, but also then it absolutely empty will not become. In it fields – gravitational, magnetic will still work, and they, though are not substance, represent matter existence form.
The similar situation makes think on a basic possibility of existence of emptiness.
Torricellian emptiness
"The nature does not tolerate emptiness" – it Aristotle's saying many centuries were an axiom for science. The principle of operation of the pump was considered as one of its confirmations: when the piston rises, under it the emptiness is formed. The nature seeks to fill immediately it with something therefore behind the piston water directs.
To a certain extent this principle worked. But in 1640 the duke Tuscan wanted to decorate a garden of the palace located on the hill, a fountain. Water was supposed to be pumped from a pond which was at a hill foot. Despite all efforts of masters, water from a gushing pipe did not go. Nobody could understand what occurs: "fear of emptiness" had to drive water on any height! Three years later the court mathematician E. Torricelli explained the failure reason by means of the known experience: in a cup with mercury overturn a tubule in which there is a mercury too. "Live metal" slightly falls, forming a column, and over it – the emptiness which received the name Torricellian. Thanks to this experience was not only atmospheric pressure is opened, but also the idea about mythical "fear of emptiness" is disproved. However, Torricellian emptiness was not completely empty too, it was filled by mercury evaporations, but for the time was also it enough: the emptiness can quite exist in the nature.
Emptiness in terms of different sciences
Considering ambiguity of a concept of emptiness, each science puts the value in this word, and there are even different terms for designation of emptiness. One of such terms – a vacuum that in translation from Latin means "empty". So call space where there is no substance, but there are fields. It is necessary to distinguish a technical vacuum from a physical vacuum – the space filled with strongly rarefied gas. It happens, for example, in electron beam tubes, the vacuum cleaner or in vacuum packing for products. In astronomy by the term "voyd" which is translated from English as "emptiness" too designate space where there are neither stars, nor galaxies. But also such space is not absolutely empty: in it there can be protogalactic clouds and also dark matter. There is a concept of emptiness and of computer science. In a different way it is called the zero index and represents the variable which is not referring to any object.