If you imagine that the nucleus had increased to the size of an orange, then the electrons will appear as the point diameter, no thicker than a human hair, fast racing on the orbits distant from the core for several kilometers!
A huge space between them - than it is filled? Nothing, emptiness ?!
In the language of science is "nothing" is called physical vacuum . That is a vacuum in terms of modern physics, we'll talk today.
OMNIPRESENT ETHER
Let us agree at once: we are not talking about a technical vacuum - a rarefied gas of very low pressure, which are widely used in various electronic devices from the light bulb to the tube. The gas pressure therein is usually 10 -6 -10 -7 mmHg. But at the same time in one cubic centimeter volume contained neither more nor less - a few billion atoms or molecules of the gas! The deeper the vacuum required in accelerators - to 10 -10 mmHg. But in this case, in one cubic centimeter it is still a million particles. Even the high vacuum - the space - can not, strictly speaking, be called emptiness: for each "cube" of interstellar space in an average of two or three particles.
The object of our conversation - the emptiness, the space in which we can not see anything, not a single particle, a single quantum of light. It would seem, what to say, nothing is nothing! What can we say about anything? This "absolute nothing", the complete absence of any kind was the matter, and imagine something impossible.
So we have a little sin against the truth and for the sake of clarity, to replace the physical vacuum of his closest model - the vacuum of space.
From the incredible vistas of space comes to us the light of the stars. With the help of radio waves the Earth is communicating with the spacecraft. All this is possible because both the light and radio waves (both are nothing else than electromagnetic waves) is very well distributed in the vacuum of space. But how can wave to move through anything?
Remember, sound, that is, the elastic vibrations of the particles of matter are well transmitted through air, water, solid. And it does not apply in the emptiness, in which there is a substance, and hence there is nothing to fluctuate. Or wave at the surface of the water? Clean water will disappear and the waves.
So, for the propagation of the waves need some material medium, vehicle vibrations. They are no exception and electromagnetic waves - they also need a mediator. So, despite the absence of the substance, the vacuum is still not completely empty ?!
But what he then filled, if not substance? This question troubled the minds of thinkers in ancient times. According to Anaximander, Democritus and their followers, the vacuum (they call him Amer , or apeiron) is a material medium that fills a universal space and atoms of matter are indivisible vacuum clots (Apeiron, amer) - something like dense clumps that It can sometimes be found in the jelly.
On a strictly physical terms very similar idea was first formulated in the second half of the XVII century Dutch scientist Christiaan Huygens. World Space, he believed permeated ether - a special matter, weightless and transparent. This matter and serves as a carrier light waves, similar to how air is the carrier of the sound. After Huygens English Physics Faraday and Maxwell considered the ether as a carrier no longer light waves, and in general all types of electromagnetic fields. Unlike ordinary ponderable matter, which is present only in some areas of space and one to YaV impenetrable ether omnipresent, infinite and permeable.
For the first time in the history of natural vacuum (ether) was endowed with well-defined physical properties. Now it is not "absolute nothingness" and more or less concrete "something". Allowing pretty well solve the problem of electromagnetic fields, the concept of a world ether is very deeply ingrained in the minds of physicists of the XIX century. So strongly that in the early XX century, continued attempts to experimentally detect the etheric matter.
The failure of many such attempts some physicists pushed to an extreme measure: they announced that the ether, in principle, do not see any instruments.
DIRAC SEA
When there was Einstein's theory, the attention of physicists shifted to mastering the global properties of space-time. As well as their development (or fight with them). Perhaps on this very quickly for many it was on the air.
Lost, but not all, including Einstein himself. His theory explains well the geometric structure of the global space, it, so to say, architecture. But to say, the material from which built this great building, she could not. Moreover, introduced in 1916, Einstein's theory of gravitation predicted that in the space other than electromagnetic waves can propagate also gravitational waves.However, what is the material environment, the "sea", on which these waves travel?
They say: "A holy place is not empty." Quantum theory of the structure of matter and experimental discoveries that accompanied Physics 20-30-ies of the century brought with them new ideas about the structure of matter and vacuum. Of course, to see the structure of the vacuum itself it was not possible, as well as the "feel" of what it is made. The vacuum was still everywhere and nowhere.
The first in a new way to look at the vacuum managed in 1931 when a young English physicist Paul Dirac. .. Solving the problem of the motion of a single electron in a space free of any other particles, fields, forces and so on, he received two values for the electron energy - positive and negative. With positive energy it was all clear, but it is negative energy? What is the physical meaning of it?
Of course, Dirac could well do as we are doing by calculating, for example, the length of the hypotenuse of a triangle by the Pythagorean theorem. Receiving two values, Square Root - positive and negative, we reject the latter as meaningless.Negative length of the interval can not be? Just as it may seem physically meaningless negative energy .
Yet Dirac tried to make sense of the resulting value. What if the negative energy does not that make sense? It may be that the second solution belongs to a certain mirror counterpart of the electron? So there is a crazy idea at first glance.What if the vacuum is not empty, but rather filled to electrons with negative energy? It turns out a kind of infinitely deep well with an infinite number of cells, each of which sits on the electron. Jump out of this hole the electron can only get enough energy for this - the more, the deeper he sits. When this does happen, the electron is in our real world, and in a vacuum, in the place where he sat, a hole is formed. At this point, there is a positive charge equal in magnitude to the charge of an electron.
The same is true in vacuo. The hole in it - a real particle is no less real than the electron. It was first predicted the positron - electron antipode. Because of the vacuum of nothingness, they are born in pairs. After wandering in our world, the electron can go back into the vacuum. But it can only sit in its cell, because all the other busy. Therefore, our wanderer must meet a hole that is a positron, and provzaimodeistvovat with him. After that the electron and hole will disappear, dissolve in a vacuum.
Dirac replied to the question why the electrons in a vacuum is not observable. See electron can only be if it somehow provzaimodeistvuet with the physical device, it will give itself a signal. But any interaction of bodies is a change in their energy. By interacting with the device, an electron in a vacuum must somehow change their energy, move to the former place in the pit to another. But where? Yama something full to overflowing, all the cells are occupied. That accounts for the electron to sit in his cell and go unnoticed.
In 1932, the theoretical prediction of the Dirac brilliantly confirmed in an experiment: in one of the photographic plates exposed to cosmic rays, was found trace particles of the same mass as the electron, but positively charged. So positron became a full member of the family of elementary particles. Later list antiparticles added antiprotons, antimesons, antihyperons and a variety of other anti.
But if the proton has its antiparticle, it means that there must be a vacuum and filled with protons is not yet born. Just as neutron vacuum , meson, and so on. So emptiness! So little by little, the physical vacuum finds its material content, allowing contradictions, which was unable to cope old broadcast in classical physics of the XIX century.
FOAM VACUUM
"Crazy" Dirac's ideas gave rise to ideas quite fantastic.
Imagine that we are armed with extremely powerful microscope, giving a glimpse into the world of incredibly small scales - many billions of times smaller compared to the size of the elementary particles. If that were possible, we would see a complex structure such as fine-grained lather. This "foam" is the vacuum matter, which, according to scientists, must have enormous density - 10 93grams per cubic centimeter. This huge figure is easier to feel, if we imagine that in one cubic micron pressed tens of trillions metagalaxies!
How hidden all the colossal mass, and hidden so securely that the vacuum for us looks completely empty? The answer is to be found in the so-called gravitational mass defect. Infinitely large vacuum density generates an infinite strong gravitational field that bends space so that the vacuum energy is, as it were sealed in the cells "foam." Therefore, we can not find it in any device - vacuum looks empty for us.
(Something remotely similar happening in the collapse - gravitational collapse - massive star, when a strong gravitational field, closes the space in which lies shrinking star with all his weight, the radiation energy of the image of "black hole", which we have not seen, and for us as it not. there.)
some points still no energy blockage is very reliable, and the energy spills over into our world. The cell "foam" as it breaks, and against the background of the empty space appear small bunches (portion, rays) in the form of elementary particles of energy.
So from the point of view of physics, vacuum all elementary particles, nuclei, atoms and even the stars and the galaxy is none other than as a result of quantum fluctuations of the vacuum - no more than spray from the waves, raging ocean of energy in the vacuum. Moreover, in comparison with a giant vacuum density is now our common matter looks infinitely rarefied, almost empty!
As physics progressed deeper into the matter, in the world ever smaller scales permanently opened more intensive sources of energy. At the core it was the latent energy is much greater than in the atom. Maybe in the proton, built of quarks, it even more? A vacuum in the cells, trillions of times more compact than the proton energy, respectively, in trillions of times more?
And it is not impossible that one day people will learn to "uncork" the cell and use the boundless energy of the vacuum reserves.