The natural change in the position of the Earth in relation to the Sun during its movement in orbit while maintaining a certain inclination of the axis of rotation determines the position on the Earth of the lines of the tropics and polar circles, limiting the belts of illumination (astronomical heat belts). They stand out depending on the midday height of the Sun and the duration of illumination (from the length of the day).
Between the tropics (north - the Tropic of Cancer and the south - the Tropic of Capricorn) lies a hot astronomical belt, within which the Sun twice a year stands at noon at its zenith. At the equator, these moments are separated by equal time intervals of 6 months (March 21 and September 23). In the tropics, the Sun is at its zenith only once a year - on the days of the solstices (in the northern tropics - June 22, in the southern - December 23). In the belts located between the tropics and the polar circles, in moderate astronomical belts, The sun does not appear at its zenith, but within 24 hours there must be a change of day and night, and their duration depends on the season and latitude. In the polar circles, the Sun does not rise above the horizon higher than 47 °, but in summer it may not hide behind the horizon for a whole day. In winter, the sun is not shown at all throughout the day. North of the Arctic Circle and south of the South Arctic Circle are cold astronomical belts... They differ in that at a low position above the horizon (less than 47 °) the Sun does not hide for up to six months (at the poles) and the same period of time does not appear (Tables 2, 3).
A total of 24 astronauts will participate in various lunar missions, 18 of which are still alive. Today they are the only people who have traveled to another world. For this reason, they are also the only humans to face the danger of radiation from the interplanetary environment.
Many of the neoliberals of the Apollo missions use the radiation argument precisely to refute the viability of lunar missions. These conspirators claim that interplanetary ionizing radiation and the Van Allen belts would kill any person who went outside Earth orbit, ergo, trips to the moon were montage. Of course, these revisionist theses do not have all the bases, but, nevertheless, the dangers of cosmic radiation are a reality and pose a problem for future interplanetary travel.
The higher the Sun is above the horizon, the more solar heat is received by the surface on which its rays fall. Therefore, the belts between the tropics are hot, the belts between the polar circles and the poles are cold. The intermediate (located between the tropics and the polar circles) belts in terms of the amount of heat received from the Sun are moderate. The lines of the tropics and polar circles can be taken as the boundaries of the thermal zones only conditionally, since in reality the temperature is determined by a number of conditions that depend primarily on the nature of the surface. But these lines, of course, are the boundaries of belts with different durations of illumination by their sunbeams.
The location of the line of the tropics and polar circles depends on the angle of inclination of the axis of rotation of the planet to its orbit. If the Earth's axis did not have an inclination to the orbit, these lines would not exist at all, and the belts of illumination (astronomical heat belts) would not stand out. This situation exists, for example, on Mercury. On a planet whose axis of rotation is inclined to orbit by 45 °, at latitudes 45 ° N. and y. on the day of the summer solstice in the corresponding hemisphere, the sun's rays fall vertically (as on the earth's tropics), and on the day of the winter solstice, the sun does not appear over the horizon (as on the earth's polar circles). Moderate astronomical belt on such a planet will not exist at all.
A change in the inclination of the planet's rotation axis to its orbit causes the expansion or contraction of astronomical heat belts (light belts).
The result of the rotation of the Earth around its axis and the resulting change of day and night is circadian rhythm processes in geographic envelope Earth. During the day, the amount of solar energy received by the surface naturally changes, the temperature, humidity, Atmosphere pressure, air movement. Organisms are sensitive to these changes, which in turn affect their environment. The daily rhythm of the processes manifests itself against the background of their annual rhythm, conditioned by the movement of the Earth around the axis, by the change of seasons and expressed in the regular change of phenomena in nature.
The main regularity in the distribution of heat on the Earth - its zoning - makes it possible to distinguish thermal, or temperature, belts. They do not coincide with the lighting belts formed according to astronomical laws, since the thermal regime depends not only on lighting, but also on a number of telluric factors.
On both sides of the equator, up to approximately 30 ° N. sh. and y. sh. located hot belt, limited by the annual isotherm 20 ° C. Within these limits, wild palms and coral structures are widespread.
Understanding the nature of this phenomenon is critical if we want to travel beyond Earth. Sources of ionizing radiation in space. Ionizing radiation in space comes from three main sources: cosmic rays, the magnetic fields of the Earth and the Sun. Cosmic rays are interstellar and even intergalactic particles that occur in some of the most scenic and violent places in the universe. Approximately 90% are energetic protons and 8% are helium nuclei. The remaining 2% are composed of electrons and other heavy nuclei.
In the middle latitudes there are moderate temperature zones. They are limited by isotherms 10 ° Since the warmest month. The boundary of the distribution of woody plants coincides with these isotherms (the lowest average temperatures at which tree seeds ripen, 10 ° C; with a lower monthly amount of heat, forests do not renew).
In addition to charged particles, cosmic rays can generate neutrons - and other particles such as muons or positrons - by colliding with various materials, expanding their deleterious effects. The permeability of these particles in a substance changes depending on their energy and type.
Cosmic rays are characterized by an extremely wide range of energies, so that its danger to humans varies considerably. In any case, the average flux of cosmic rays near the Earth is very low. Stream of different types of cosmic rays based on their energy.
In subpolar latitudes extend cold belts, the polar boundaries of which are the 0 ° C isotherms of the warmest month. They generally coincide with the tundra zones.
Around the poles are belts of eternal frost, in which the temperature of any month is below 0 ° C. Here lies eternal snow and ice.
The hot zone, despite its large area, is quite homogeneous in terms of heat. average temperature year varies from 26 ° at the equator to 20 ° C at the tropical limits. Annual and daily amplitudes are insignificant. The cold and eternal frost belts are relatively homogeneous thermally due to their narrowness. The temperate belts, spanning latitudes from subtropical to subpolar, are thermally highly heterogeneous. Here the annual temperature at some latitudes reaches 20 ° C, while at others even the temperature of the warmest month does not exceed 10 C. Latitudinal differentiation of temperate zones is revealed. Due to its continental nature, the northern temperate belt is also differentiated in the longitudinal direction: in the annual temperature variation, the coastal and inland positions are clearly reflected here.
Cosmic ray flux in low orbit depending on magnetic latitude, solar cycle and particle type. The sun promotes interplanetary radiation with solar wind particles and high energy photons. The solar wind is formed by a relatively high flux of protons, alpha particles and heavy ions, although the average energy of these particles is much lower than that of cosmic rays. In order not to complicate life excessively with solar physics, these "attacks" of the Sun are usually given the general and imprecise name of "solar storm".
Most of the particles generated in these events are protons, although their energies and densities are very different. Its effects will depend on the trajectory of the particles relative to the position of the astronauts in Solar system... Without adequate protection, an astronaut in interplanetary space, exposed to radiation from events of these characteristics, could receive a lethal dose.
V temperate zones in the most nervous approach, subtropical latitudes stand out, temperature regime which provides the growth of subtropical vegetation, moderately warm latitudes, where heat ensures the existence of broad-leaved forests and steppes, and boreal latitudes with the amount of heat sufficient only for the growth of conifers and small-leaved trees.
In addition to particles, the Sun can also emit significant amounts of X-rays and gamma rays during flares. The structure of the spacecraft is usually much more effective at blocking this electromagnetic radiation than when it comes to particles.
However, it is very difficult to completely eliminate this flow. The last source of radiation that we must mention is the earth's magnetosphere. The magnetic field of our planet protects us from the energetic particles of cosmic rays and the Sun, but in turn captures some of these particles in certain areas. These zones are called the Van Allen radiation belts and are a major hazard to manned low and medium orbit missions. They mainly consist of two electron belts and one of the protons.
With the general similarity of the temperature zones of both hemispheres, the thermal dissymmetry of the Earth relative to the equator is clearly evident. The thermal equator is displaced to the north relative to the geographic one, the northern hemisphere is warmer than the southern, in the southern temperature it is oceanic, in the northern - continental, the Arctic is warmer than Antarctica.
The thermal conditions of the belts naturally violate mountainous countries... Due to the decrease in temperature with height in them
Diagram of the Earth's radiation belts. Distribution of flow in electronic belts. And 35 ° W. In this region, the density of protons in low orbit is much higher than the density found in the rest of the globe... Distribution of the flux of proton belts.
Proton flux in the South Atlantic anomaly. While seconds can be avoided - or at least minimized exposure time - the emission of solar energy protons is unpredictable and therefore much more dangerous. The flux of various types of particles of cosmic radiation by their energy. Fortunately, the most energetic particles are also those with the lowest flux.
The greatest annual amplitudes from 23 to 32 ° С are typical for the middle belt largest area continents, in which different heating and cooling of continents and oceans, the formation of positive and negative temperature anomalies cause different temperature variations on the ocean and in the interior of the continents.
Useful advice:
I bought a new apartment and now I am choosing a huge TV from that will wake up the whole house and all the neighbors when I turn up the volume a little.
Measurement of radiation dose. Before continuing, we must briefly introduce the units used to measure the absorbed radiation dose that astronauts receive during a space mission. The originally preferred unit for measuring absorbed dose was rad, defined as dose ionizing radiation required to cause the absorption of 0.01 J of energy per kilogram of matter. The problem with these units from a manned flight perspective is that they do not account for different radiation effects depending on the nature of the substance affected.
