A photo from open sources
The sun, in the bowels of which the temperature reigns about 13,000 000 ° С, and on the surface – about 6000 ° С, emits every second 3.8-1026 J of energy. Only one two billionth comes to the Earth a fraction of the energy of the sun, but it is enough for exaltation and development of life.
The sun sends two types of radiation to Earth: electromagnetic wavelengths from millionths of a millimeter to tens of kilometers and flows of charged particles – corpuscles moving at a speed about 1000 km / s and after one to two days reaching the Earth. Part cosmic radiation comes from outside the solar system.
From most of the cosmic radiation, the inhabitants of the Earth reliably protected by a complex system of various physical shells, through which penetrates only visible light, a small proportion adjacent to him ultraviolet and infrared rays and a narrow section radio waves. At the approaches to the Earth, corpuscles also linger, representing mainly hydrogen nuclei (protons) and helium nuclei (alpha particles), as well as a small number of heavy nuclei elements.
First of all, the earthly atmosphere is a saving screen. However, by delaying one part of cosmic radiation, the terrestrial the atmosphere freely enough passes another. Substantially helps the atmosphere the Earth’s magnetic field, which caused the formation ionosphere and two belts of charged particles around the Earth. Interior the equatorial belt with the highest particle density is located on a distance of about 3600 km from the surface of the planet. He girdles Earth ring from 35 ° S. w. up to 35 ° c. w. Outer belt consisting of mainly from electrons, spreads to latitudes of 65 °. Position in space, the volume and density of particles in it vary greatly, the distance from the Earth varies between 25-50 thousand km. the main thing the protective property of these belts is that they act as traps for particles coming from the Sun with high energies. A magnetic field, deviating them from the direction to Earth, involves in a circuit around the planet. It is noticed that if you move from the equator to the pole, then the number of charged particles falling to Earth increases slightly (approximately 10%). In the stratosphere, the latitudinal effect is several times more than at sea level. At the upper boundary of the atmosphere cosmic ray intensity at the equator is 5 times less than in the polar regions. This is affected by the lack of permanent belts of charged particles over the polar regions. However it is increased intensity of the corpuscular flow in the circumpolar areas are relatively small and not dangerous of life.
Thanks to the magnetic field, our planet is surrounded by the ionosphere – a layer of rarefied ionized gas at altitudes from 70 to 500 km. Powerful electric currents flow in this layer. Ionosphere and the lower layer of ozone absorbs ultraviolet and X-rays of the Sun, which, having reached the surface, could destroy her life. The ionosphere has another wonderful property. Like a mirror, it reflects radio waves and makes, thus, radio communication on Earth on large distance.
The intensity of cosmic radiation reaching the surface planet depends on the intensity of solar radiation, and from the magnetic field of the Earth and, as a result, from screening effect of the ionosphere and layers of charged particles.
Although the Earth is at a distance of about 150 million km from the Sun and protected by the atmosphere, ionosphere and belts of charged particles, we we feel very subtly what is happening on the sun. Every 11 years streams of solar gases soar up hundreds of thousands of kilometers, rushing into interstellar space. Such activity lasts 2-3 years, and then fades. In the period of maximum solar activity on Earth there are bright auroras, prolonged (up to 10 days) violation in the polar areas of radio communications, magnetic storms are played out, electric ones begin to flow in the earth currents of such power that often telephone and telegraph devices stations become worthless. Often after solar flares in near-Earth spaces are invaded by flows of charged particles very high energies, representing the detached “pieces” of the solar atmosphere. A. L. Chizhevsky and his followers established that organic life on earth reacts very sensitively to the 11-year cycle solar activity. The frequency of epidemic diseases, their the beginning, development, and ending rhythmically follow the cycle of our daylight. The sun turns out to be a great conductor earthly life processes.
It is likely that there are larger cycles of change solar activity whose effects on organic life Earth can be even stronger. However, the lack of necessary quantitative changes over the long term does not allow talking about this in the affirmative.
The Earth’s magnetic field is very small in magnitude. It is hundreds times weaker than the field between the horseshoes of an ordinary school magnet. However, the earth’s field occupies a huge volume, stretching for dozens thousand kilometers from the surface of the Earth. And since the energy of magnetic field is proportional to the volume, then the influence of the earth’s field on processes in The surrounding area of the planet is very large. If the field disappeared, Earth would lose protection from charged particles emitted by the Sun and trapped in magnetic traps. The globe would undergo bombardment by cosmic particles of huge energies. We are not could see the unforgettable beauty of the auroras, as they would occur on the sunlit side of the earth instead areas shrouded by polar night where particle paths deviate under the influence of a magnetic field.
Do we have full confidence that the magnetic field Earth constantly existed throughout the entire period of its life as planets? It is impossible to unequivocally answer this question now. To get a little closer to its resolution, consider the change magnetic field strength over time. In recent years arose a new branch of science – archeomagnetism, studying the magnitude and direction of the residual magnetization measured in samples taken from stoves (burnt bricks and pottery dishes). In all cases, when the firing temperature reached 800 ° S. i.e., exceeded the Curie point, the grains contained in the baked clay magnetic minerals have become very stable over time thermo-residual magnetization. In the 60s, geophysicists E. Tellier and S.P. Burlatskaya investigated the thermal magnetization of the calcined clay samples by man (the firing time is set by archaeological data). This allowed us to construct a change curve. geomagnetic field strength over the past 5000-6000 years. From of our days, the magnetic field is gradually increasing, reaching maximum around the beginning of a new era. At that time it was 1.5 times more than modern. Then the field begins to decrease up to IV thousand B.C. The magnitude of the magnetic field 5000-6000 years ago was 2 times less than at present. If you move even further along timeline, the field will again begin to increase, although, as notes S.P. Burlatskaya, for reliable conclusions, the data are not enough. So Thus, there is no doubt that the main dipole part Earth’s magnetic field experiences vibrations, probably having periodic in nature. Possible period of field changes exceeds 6000 years old. It should be noted that if the maximum field values measured accurately, then the minimum field strength unknown.
With the help of paleomagnetism, it was possible to establish one interesting physical phenomenon, accompanied by a sharp and significant magnitude by a decrease in magnetic field strength. The study magnetic properties of the geological section of rocks showed that during sedimentation, the north and south magnetic poles the sign-magnetic field was inverted). IN some geological periods had several inversions magnetic field. At least nine field inversions occurred in the last Pliocene-Quaternary segment of geological time, lasting 11 million years. The last magnetic field inversion on our planet marked at the beginning of the Quaternary period, i.e. 500-800 thousand years ago. It is believed that on average the field of one sign does not exist less than 500 thousand years.
At the moment of inversion, the field value decreases to 0.3 from normal, and given the preceding decrease some “jump” of its magnitude, then the total amplitude of the field decrease is approximately equal to its normal value. Magnetic field inversion process Earth is studied only as a first approximation. It is possible that in the period minimum field values at separate intervals The magnetic field on Earth was less than 0.3 from normal.
It’s easy to understand that the organic life of our planet is offensive magnetic field inversion was perceived as a grand catastrophe. Indeed, a decrease in the magnetic field by 3 times should cause a proportional increase in the level of cosmic radiation by The earth. The decrease in field strength occurred throughout the length of time measured by centuries during which the animal world was unusually difficult to adapt to sharp increase cosmic radiation.
Recently, Canadian geologist J. Crane suggested that the reason for the mass extinction of organisms was not the effect of radiation, but directly reducing the magnetic field in the process changes in its polarity.
Crane substantiates his hunch by experiments, during which living organisms were placed in an artificial magnetic field with less than Earth’s tension. After a 72-hour stay in such a field, the ability of bacteria to multiply decreased by 15 time; impaired motor reflexes in tapeworms and mollusks; decreased neuromotor activity in birds; in mice metabolic disorders. With a longer stay changes in tissues and infertility occurred.
According to Creia, the effect of a magnetic field on an organism can be reinforced by climate change, winds, lower temperatures plus a stream of cosmic rays; and judging by the ancient fossils, the overall result of all these influences on some living organisms can be catastrophic.
In the evolution of the organic world of the era of inversion, perhaps represented a kind of “sieve” through which occurred natural selection of all life on Earth.
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