The solar eclipse is a phenomenon quite rare and unusual, making a big impression on people. You can imagine that when some people not informed suddenly starts seeing in front of the Sun fades and becomes dark, his first thought would be that came “at the end of the world”. For astronomers, this spectacular show, is a rare opportunity for research. The first such phenomena were observed by mankind in the ancient times. Earlier people when a solar eclipse were lost and feel wild fear of this mysterious phenomenon. As a rule, among ordinary people there felt that at this point some sort of terrible dragon tries to destroy the Sun, and it must be protected. As did the solar eclipse lasts for a short time, then plan the locals always worked. They are armed with military weapons and went to “war”, after the offence, people returned to their homes quiet and satisfied that drove away the evil spirits and were saved by the Sun. It is also known that the first Eclipse in human history it was during the reign of Chung-Kang, the fourth Emperor of the dynasty of Hen. It is to this period coincides with an entry in one of the books of ancient China-“Šuczin” (“book of history”). The date of the solar eclipse installed only in the nineteenth century-October 22, 2137 BC.
By the way, each solar eclipse in one way or another connected with historical events. So, it happened on August 3 431 BC, during a War in Greece. The exact date of the Eclipse has helped restore some of the moments of the war, including the date. Solar Eclipse which happened during that period of time, was not complete.
Today it is well established that there is a solar eclipse. It is a natural phenomenon, the essence of which is that the Moon eclipses the Sun. A solar eclipse is when the Moon, Earth and Sun line up in one line, and the new moon. So this astronomical phenomenon is far from each new moon. Depending on how far the Moon covers the Sun, allocate the total or partial eclipse. Of course, it’s all in the shadow of the Moon, which can be of different sizes, and the man who is on the surface of the Earth and enters the shadow zone will be able to view the total solar eclipse. The duration of such astronomical phenomena is just a few minutes, because the speed of shadow Moon is 1 km/s as a minimum. Full Eclipse is 6:0, and began taking in the western part of the Earth at sunrise, and ends in the eastern part of the sunset.
HOW AND WHY DO SOLAR ECLIPSES OCCUR?
As you know, the planets and their satellites do not stand still. The earth revolves around the Sun, and the moon revolves around the Earth. And from time to time there are such moments, when the Moon in its motion is fully or partially covers the Sun. The solar eclipse is the shadow of the moon on the Earth’s surface. This shadow has a diameter of about 200 km, which is many times smaller than the diameter of the Earth. Therefore, the solar eclipse can be observed only in a narrow band on the way the Moon’s shadow
Moon shadow on the surface of the Earth during a solar eclipse
If the observer is in a strip of shade, he sees a total solar eclipse, when the Moon completely hides the Sun. The sky darkens, and it may become visible stars. Gets a bit cooler. The birds had fallen silent, frightened by the sudden darkness, trying to take cover. The animals begin to show concern. Some of the plants leaves are folded.
Phase of a total solar eclipse
The observers, who are near the fringes of the Eclipse, the partial solar eclipse can be seen. When private Eclipse the Moon passes over the Sun’s disk is not exactly centered, and hides only part of that drive. The sky gets dark much weaker than a full Eclipse, the stars are not visible. An Eclipse can be observed at a distance of about 2 thousand kilometers from the zone of total eclipse.
Partial solar eclipse
Solar eclipses always happen at new moon. At this time the moon on the Earth is not visible, because the side of the Moon that faces Earth is not illuminated by the Sun (see Figure 1). Because of this, it seems that during the Eclipse the Sun covers the black spot we see from now here. The Moon casts a shadow towards Earth, looks like sharp converging cone. The spearhead of this cone is a little further on the planet. So when a shadow falls on Earth’s surface, it is not a point, and a relatively small (150-270 km across) black spot. Following the Moon this spot moves over the surface of the planet at a speed of about 1 kilometer per second:
Solar Eclipse July 22, 2009 scheme year from NASA site
Therefore, the shadow of the moon with a great rate moves on the Earth’s surface and can not permanently close one place on the globe. The maximum possible length of a full phase-only 7.5 minutes. An Eclipse lasts about two hours.
Solar eclipses on Earth-a truly unique phenomenon. It is possible because on the celestial sphere diameters of the Moon and the Sun are almost identical, although the Sun’s diameter is about 400 times the diameter of the moon. And this is because the Sun is about 400 times further from the Earth than the moon. But the orbit of the Moon is not round and elliptical. So in the moments conducive to the occurrence of eclipses, Lunar disk may be larger than the Sun, equal to, or less than it. In the first case there comes a total eclipse. In the second case, too, a total eclipse, but it only lasts a moment. And in the third case, an annular eclipse: the Moon’s visible disk of dark around the gleaming ring the surface of the Sun. This Eclipse can last for up to 12 minutes. During a total solar eclipse can be observed the solar corona-the outer layers of the atmosphere of the Sun, which in normal light of the Sun is not visible. This is should be a stunning spectacle.
Naturally, when the private you will see the Eclipse is not the same effect as the total eclipse. The astronomers have excreting Annular solar eclipse, the essence of which is that the Moon passes by the Sun, and a diameter smaller than the last, it turns out that during the Eclipse, you can see the Sun around the circumference. The frequency of a solar eclipse is usually 2-5 eclipses per year. And not always all these phenomena will be exactly the total solar eclipse. Astrologers predict that the longest total solar eclipse will occur July 16, 2186, and his time is-7 minutes 29 seconds. Would like to provide a chronology of solar eclipses over the last 10 years. Of course, there are few cases of this phenomenon, but the most basic.
1. February 5, 2000 year-private solar eclipse.
2.21 June 2001 year-total solar eclipse. The phenomenon is best seen those people that were at this point in the Equatorial part of the southern hemisphere. The width of the Moon’s shadow when the Eclipse reached 200 kilometers and a length of 373320 km. Time: 12:04:46;
3. June 10, 2002 God-Annular solar eclipse. Best visibility was in the zone of the northern hemisphere. The duration was approximately 23 seconds. The width of the shadow of archery was only 13 kilometers and a length of 373320 km. Time of the event: 23:45:22.
4. May 31, 2003 year-private solar eclipse. Start time: 9:30:17. Place-Barnaul.
5. October 3, 2005: annular eclipse. Maximum phase could be observed in areas to the South of Europe (Portugal and Spain) and Africa.
6. March 29, 2006 year there was a total solar eclipse, which is well seen in the western part of Russia.
7. March 19, 2007 year-private solar eclipse, which can be seen in North America.
8. August 1, 2008 year-total solar eclipse, the active phase of which had been in Novosibirsk. Start time-17:44:02. Duration: 2 minutes 18 seconds.
9. July 22, 2009 year-total solar eclipse. It can be seen in many countries of the world-India, Nepal, Bhutan, Myanmar, Bangladesh and others.
10. January 15, 2010 year-Annular solar eclipse.
11. January 4, 2011-private solar eclipse. Place-northern hemisphere. Start at 10:38. This phenomenon of humanity would be able to see only in the year 2015.
Geometry of solar eclipses
In its motion around the Earth the Moon obscures the stars, planets, and the Sun. The phenomenon when the observer the Moon fully or partially covers the Sun, called the solar eclipse.
Solar eclipses can occur only when the new moons, when the Moon passes between the Earth and the Sun, but not at all, as the moon can move away from the ecliptic by about 5°, and the diameters of the solar and Lunar discs are close to 0.5°. As we know from physics course, spherical body (Moon) light gives rise to long light source (the Sun)-shadow and widening Penumbra. Observer in the Penumbra, sees the partially-closed Sun from shadow-in general it does not see.
Total phase-the spectacle of striking beauty, are extremely rare. The bright disk of the Sun is closed, and the solar corona becomes visible around education, located near the star, this does not effect the Earth’s atmosphere. Under normal circumstances, it is difficult to see on the ground the Crown due to the high brightness of the luminaries and strong scattering of light in the atmosphere. A rare opportunity to examine the Crown and get more information about solar activity makes monitoring a complete phase of great value to science. Due to the fact that the moon has a small footprint on the Earth, the Eclipse is visible only on the portion of the illuminated hemisphere. Shadow of the Moon in space converges, but usually it happens that the surface is closer to the Moon than the place where the shadow is drawn in the point. A small patch of shade, with a diameter of 100-300 km, moving, forming a strip of Eclipse, which is the total phase. Eclipse, where on Earth is the total phase, is called complete. The maximum length of the total phase is 7.5 m. In the areas of bands usually fill the expedition.
Total solar eclipse
It sometimes happens that the surface is further from the Moon than the shadow, where it becomes the point. Being close to the Sun-Moon, Earth observer would not see the full closure of the disk of the Sun, as the moon will have a lower apparent Angular diameter. Instead of the Crown will be visible ring of the solar disk. This Eclipse is the circle. Recent observations are of high scientific value, however the band where the Eclipse can be seen as a circle, are calculated, and they also leave the expedition. The maximum duration is 12 m rings appear. Annular eclipses are rarer than total.
The reason for the situation when the Moon is farther away from the observer, lies not only in the greater distance earth-moon at the moment, but that streak may be the Eclipse of the Moon in more parts of the globe, that is at the edges of the illuminated hemisphere. And if a band passes as remote sites and closer, it may be that in the first case in the annular eclipse, in full, with the stripe is continuous (only changing its thickness). This Eclipse is a circularly-complete and even more rarely than previously described species. If the Earth is only Eclipse Penumbra Moon and band simply does not exist, the Eclipse is called private and on the ground you will see only the private phase. Such eclipses happen pretty often.
Generally speaking, the average frequency of Central solar eclipses on Earth-one per year. But limited the visibility allows you to move this phenomenon become rare. Usually for one locality to see one private Eclipse in several years and full of high frequency and there was talk between them can take many decades or centuries. The maximum number of solar eclipses in a year are 5.
When listing the types of eclipses:
Private-where on earth can only be seen private phase.
Full-where on earth you can see the full phase.
Annular-the same, when you can see the Sun only in the form of a ring.
Circularly-complete-when visibility in different areas as annular and total.