Cosmic rays. If there is no air ions, that charged the electroscope must retain their charge indefinitely. However, experience has shown, the electroscope slowly loses its charge.
Initially this phenomenon was explained by an ionizing action of a radioactive radiation of the Earth. If so, as the removal from the Earth's surface ionizing radiation air must wane. In 1912 g. using balloons was established, the intensity of radiation increases with increasing altitude. Therefore, this radiation does not occur on Earth, and somewhere in world space. So it came to be called cosmic rays.

The study of cosmic rays in the higher regions showed, they consist of peonies, protons, neutrons and other particles, among them were found many previously unknown particles. These particles were identified as secondary particles, as it turned out, they are formed in the upper atmosphere by interaction of primary cosmic particles, flying from the global space, with nuclei of atoms in the atmosphere.
Studies have shown, the intensity space obtained near the magnetic poles of the Earth approximately 1,5 times, than at the equator. The study of the deflecting action of the Earth magnetic field on primary cosmic rays have shown, it consists of positively charged particles. A lot of valuable information about primary cosmic rays obtained with the use of artificial satellites and space ships..

Currently installed, primary cosmic radiation consists of stable high-energy particles, flying in various directions in space. The intensity of cosmic radiation in the region of the Solar system is an average of 2-4 particles 1 cm2 for 1 with. It consists mainly of protons (~91%) and a-particles (6,6%); a small portion falls on the nucleus of other elements (less 1%) and electrons (~’ 1,5%).

The average energy of cosmic particles is about 10^4 MeV, and the energy of the individual particles reaches extremely high values: 10^12 MeV, and more. Where do cosmic particles and how they are accelerated to such enormous energies, still unknown. Suppose, they are originated by the explosions of novae and supernovae explosions, and are accelerated during the interaction with inhomogeneous magnetic fields in interstellar space.
The sun periodically (during outbreaks) sun emits cosmic rays, which mostly consist of protons and α-particles, have a small energy, but high intensity, that has to be considered when planning space flights.

Secondary particles also have a very high energy and by collision with nuclei cause a further multiplication of particles.

In figure. 38.1 shown fixed on the thick otoplastika enlarged picture of destruction of an atomic nucleus when hit by the particles with big energy (about 2*10^3 MeV). The trace struck to the core of the particles invisible (apparently, a neutron). The core was split into 17 particles, flown apart in different directions.

As a result of avalanche multiplication of particles in the upper atmosphere forms a cascade of nuclear downpour. In figure. 38.2 shown artificial cascade shower, obtained in the cloud chamber, blocked lead plates. A particle of high energy, passing through a layer of lead, creates a shower of particles, which with the passage of the following layers of lead create new showers.

Nuclear shower in the atmosphere fades out, when the energy of the particles decreases to few tens of MeV. The rest energy of the protons spend on air ionization; the neutrons are absorbed by nuclei, causing various nuclear reactions, and peonies, are a majority of heavy particles, apart. Resulting in a large number of photons and electrons are strongly absorbed by the atmosphere.

Neutral pions very quickly turn into two high-energy photon. In the decay of charged pions formation of new particles µ-m e R o n s, or muon s, which were opened To. Anderson in 1935 g. in the study of cosmic rays, long before the discovery of pions. The mass of the muon in 207 times the mass of the electron, t. e. is about 3/4 mass peony. Muons are the only two types of positively and negatively charged; they are denoted by µ+ and µ-. In the decay of π+mesons are formed µ+-mesons, and in the decay of π^--meson — µ^--mesons.

It turns out, what, unlike pions, muons do not participate in nuclear interactions and expend energy only by ionization. Therefore, they have high penetrating power and are so-called hard component of cosmic radiation. Muons fly through the atmosphere, and they are found even at a considerable depth below the Earth's surface.

Muons are unstable, they exist only a few microseconds and decay into other particles.
At sea level, cosmic radiation is approximately a hundred times lower intensity, than on the border of the atmosphere, and consists mainly of muons. The rest are electrons and photons and a small number of shower particles. Of primary cosmic radiation only individual particles, with extremely high energy (more than 10^7- MeV), breaking through the atmosphere.

In cosmic rays the muons, like peonies, flying at speeds, close to the speed of light, and so, due to the relativistic slowing of time before its collapse to fly long distances.