Solar system is a system of planets orbiting around a star, the Sun. Among those planets is our Earth. The solar System consists of the sun and of celestial bodies held by solar gravity. The mass of the sun is about 330 000 times the mass of the earth and makes up 99.8% mass entire solar system. The diameter of the sun is 1 400 000 km, i.e. about 109 Earth diameters. In the solar system except the sun is made up of eight planets, over 150 moons, and small bodies such as asteroids, comets and meteors.
In order of proximity to the Sun, the eight planets are mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
To measure distances in the solar system is used “astronomical unit” (AU). One AU corresponds to the distance from the earth to the Sun. Thus, the distance of one AU is nearly 150 million kilometers. For example, Jupiter rotates on its orbit 5.2 AU, i.e. the distance from the Sun is 5.2 times larger than the Earth. Continue reading
A planet differs from a star. The star is a giant ball composed of hot gases, radiant heat and light. The planet is much smaller in size. It emits no light, but rather, is warmed by starlight.
Let’s look at all the planets in order, starting with the one that is closest to the Sun. The nearest planet to Sun — mercury. The diameter of mercury is 4878 kilometers counts, i.e. equal to the Atlantic ocean. And that means mercury is much smaller than Earth.
The next planet is Venus. It’s almost the same size as our Earth. In diameter it has about 12 100 kilometers, and the Earth’s diameter is 12 kilometers 742,5. By the way, Venus rotates around the Sun in the opposite direction, from East to West. For Venus is Earth, then Mars.
Reddish color of the planet Mars has always distinguished it from other heavenly bodies of the Solar system. The diameter of this planet has 6780 miles. This is slightly greater than half the diameter of the Earth. Mars has always attracted the attention of scientists. Because the surface of this planet is visible to any shape, resembling canals. Out of all the planets of the Solar system except our Earth, on Mars it is most likely sushestvovaniya any form of life, maybe vegetable. Continue reading
Manned flights on the orbital stations
In the first decade of the era of manned spaceflight duration increased from 108 min to 18 days. Made in this period, medical and biological research (in the Russian ships “Vostok”, “Voskhod”, “Union”; in the U.S. project “mercury”, “Gemini”, “Apollo”) have proved the possibility of relatively short-term (up to 2-3 weeks) stay safe man in the space flight environment and active activities outside of the ship.
The most significant changes in the major systems of the human body were observed after flights. They were shown to decrease the body’s resistance to physical and orthostatic stress; impaired coordination of movements and regulation of the vertical posture; a reduction of body weight, hydration of the body, decreasing the volume of blood plasma and erythrocyte mass; asthenia. These changes in General increased with increasing duration of space flights and after flights, lasting 14 to 18 days, were practically significant.
Post-flight revealed improvements of indicated that to further increase the duration of flights you need to apply a system of appropriate protective and preventive measures that will facilitate adaptation of the human body to terrestrial conditions after the completion of the flight. Continue reading