Comets: the oldest inhabitants of the Solar system
J. L. Lagrange (1813) was also based on firmly established facts – the presence of comets that definitely move in elliptical orbits, including short-period. He explained the origin of comets gigantic volcanic explosions – emissions (eruption) with giant planets. It is, in principle, could explain the nature of the orbits of short-period comets. Subsequently, the views of La Grange shared and developed a number of scientists, among which the most important contribution of the Soviet astronomer S. K. Bo, who worked in this direction with the 20-ies to 80-ies of our century. He has eliminated the biggest internal difficulty is the concept of Lagrange – the necessity of the ejection of cometary masses (nuclei) with the “surface” of the giant planets with their powerful gravity fields, the overcoming of which requires an initial speed of 60 km/s and more. Giant planets also have thick (the length of many thousands of miles) and very dense atmosphere, in the middle of the twentieth century has been very problematic the very existence of a solid surface planets – giants beneath these atmospheres. Continue reading
The diversity of comets in the Solar system
The comet (from al-Greek. hairy, shaggy) – a small celestial body having a foggy view, orbiting the Sun in conic section with a very extended orbit. When approaching the Sun, the comet forms a coma and sometimes a tail of gas and dust.
Comets are placed into circulation periods:
At this time, found more than 400 short-period comets. Of these, about 200 were observed in more than one perihelion passage. Short-period comets (period less than 200 years) come from the region of the outer planets, moving in the forward direction for orbits lying close to the Ecliptic. Away from the Sun, comets usually do not have “tails”, but sometimes have a barely visible “to”, surrounding the core; together they are called the “head” of the comet. Approaching the Sun the head is increased and there is a tail. Many of them belong to so called family. For example, most of the short-period comets (full rotation around the Sun lasts 3-10 years) form the family of Jupiter. A little smaller of a family of Saturn, Uranus and Neptune (the latter, in particular, is the famous comet Halley). Continue reading
It has long been observed that the nuclei of periodic comets are depleted, with every turn they glow weaker. Not once was there a division of cometary nuclei into two parts or more. This destruction produced or solar tides, or collisions with a meteor shower. The comet, discovered by the Czech scientists Bilim (Biloy) in 1772 was observed with repeated returns with the seven-year period. In 1846 its core collapsed, and it turned into two weak comets, which after 1852 was not observed. When in 1872, according to the calculations, the missing comet should pass near the Earth, there was rain of “falling stars”. Since November 27 this phenomenon is repeated every year, though less effectively. Small solid particles of the disintegrated nucleus of a former comet Bilogo stretched along its orbit, and when the Earth crosses the stream, they fly in the atmosphere and evaporate. A number of other meteor showers.
Meteoroids — the remains of comets, visible only at the time of evaporation are called meteors. The width of meteor showers is much greater than the size of the generated nuclei.
Photographing the path of the same meteor in the starry sky, as he is projected to observers, separated from each other by 20-30 km, determine the altitude at which the meteor appeared. Most meteoroids begin to glow at heights of 100 to 120 km and has already completely evaporated at a height of 80 km . Continue reading