Meteor shower

A meteor shower is a celestial event in which a number of meteors are observed to radiate, or originate, from one point in the night sky. These meteors are caused by streams of cosmic debris called meteoroids entering Earth's atmosphere at high speeds on parallel trajectories. Most meteors are smaller than a grain of sand, so all of them disintegrate and never hit the Earth's surface. Intense or unusual meteor showers are known as meteor outbursts and meteor storms, which produce at least 1,000 meteors an hour, most notably from the Leonids; the Meteor Data Centre lists over 900 suspected meteor showers of which about 100 are well established. Several organizations point to viewing opportunities on the Internet; the first great meteor storm in the modern era was the Leonids of November 1833. One estimate is a peak rate of over one hundred thousand meteors an hour, but another, done as the storm abated, estimated in excess of two hundred thousand meteors during the 9 hours of storm, over the entire region of North America east of the Rocky Mountains.

American Denison Olmsted explained the event most accurately. After spending the last weeks of 1833 collecting information, he presented his findings in January 1834 to the American Journal of Science and Arts, published in January–April 1834, January 1836, he noted the shower was of short duration and was not seen in Europe, that the meteors radiated from a point in the constellation of Leo and he speculated the meteors had originated from a cloud of particles in space. Work continued, yet coming to understand the annual nature of showers though the occurrences of storms perplexed researchers; the actual nature of meteors was still debated during the 19th century. Meteors were conceived as an atmospheric phenomenon by many scientists until the Italian astronomer Giovanni Schiaparelli ascertained the relation between meteors and comets in his work "Notes upon the astronomical theory of the falling stars". In the 1890s, Irish astronomer George Johnstone Stoney and British astronomer Arthur Matthew Weld Downing, were the first to attempt to calculate the position of the dust at Earth's orbit.

They studied the dust ejected in 1866 by comet 55P/Tempel-Tuttle in advance of the anticipated Leonid shower return of 1898 and 1899. Meteor storms were anticipated, but the final calculations showed that most of the dust would be far inside of Earth's orbit; the same results were independently arrived at by Adolf Berberich of the Königliches Astronomisches Rechen Institut in Berlin, Germany. Although the absence of meteor storms that season confirmed the calculations, the advance of much better computing tools was needed to arrive at reliable predictions. In 1981 Donald K. Yeomans of the Jet Propulsion Laboratory reviewed the history of meteor showers for the Leonids and the history of the dynamic orbit of Comet Tempel-Tuttle. A graph from it was re-published in Sky and Telescope, it showed relative positions of the Earth and Tempel-Tuttle and marks where Earth encountered dense dust. This showed that the meteoroids are behind and outside the path of the comet, but paths of the Earth through the cloud of particles resulting in powerful storms were near paths of nearly no activity.

In 1985, E. D. Kondrat'eva and E. A. Reznikov of Kazan State University first identified the years when dust was released, responsible for several past Leonid meteor storms. In 1995, Peter Jenniskens predicted the 1995 Alpha Monocerotids outburst from dust trails. In anticipation of the 1999 Leonid storm, Robert H. McNaught, David Asher, Finland's Esko Lyytinen were the first to apply this method in the West. In 2006 Jenniskens published predictions for future dust trail encounters covering the next 50 years. Jérémie Vaubaillon continues to update predictions based on observations each year for the Institut de Mécanique Céleste et de Calcul des Éphémérides; because meteor shower particles are all traveling in parallel paths, at the same velocity, they will all appear to an observer below to radiate away from a single point in the sky. This radiant point is caused by the effect of perspective, similar to parallel railroad tracks converging at a single vanishing point on the horizon when viewed from the middle of the tracks.

Meteor showers are always named after the constellation from which the meteors appear to originate. This "fixed point" moves across the sky during the night due to the Earth turning on its axis, the same reason the stars appear to march across the sky; the radiant moves from night to night against the background stars due to the Earth moving in its orbit around the Sun. See IMO Meteor Shower Calendar 2017 for maps of drifting "fixed points." When the moving radiant is at the highest point it will reach in the observer's sky that night, the Sun will be just clearing the eastern horizon. For this reason, the best viewing time for a meteor shower is slightly before dawn — a compromise between the maximum number of meteors available for viewing, the lightening sky which makes them harder to see. Meteor showers are named after the nearest constellation or bright star with a Greek or Roman letter assigned, close to the radiant position at the peak of the shower, whereby the grammatical declension of the Latin possessive form is replaced by "id" or "ids".

Hence, meteors radiating from near the star Delta Aquarii are called the Delta Aquariids. The International Astronomical Union's Task Group on Meteor Shower Nomenclature and the IAU's Meteor Data Center keep track of meteor shower nomenclature and which showers

Alberto Leoncini Bartoli

Alberto Leoncini Bartoli is a retired Italian diplomat. In 1958 he joined the foreign service and was assigned first to the Economic Department and thereafter to the press service of the Ministry of Foreign Affairs. In 1960 he was appointed vice-consul in Berlin. From 1963 to 1967 he thereafter in Sofia. From 1968 to 1971 he was appointed to the Press Service department in Rome. From 1972 to 1976 he was appointed councilor to the Italian Embassy in Bonn. From 1977 to 1980 he headed first the Comecon and thereafter the North Atlantic Council departments in Rome. In 1979 he was promoted Minister Plenipotentiary. In 1981, he was appointed Minister Plenipotentiary to the Italian Embassy in Paris where in 1986 he was promoted first class special envoy and plenipotentiary. From July 1987 to 1990 he was appointed ambassador to Tel Aviv. From 1993 to 1996 he was appointed ambassador to Cairo. From 1996 to 1997 he was appointed chief of protocol of the Ministry of Foreign Affairs. From 1997 to 1999 he was appointed ambassador to the Holy See.

From 1999 to 2000 he was appointed Secretary General for Internal Affairs of the Sovereign Military Order of Malta. From 2001 to 2016 he was appointed Ambassador of the Sovereign Military Order of Malta to the Holy See

Inanch Bilge khan

Inanch khan or Inanch Bilge Bogü khan or Inat khan was a khan of Naimans. According to Gumilev, his Christian name was John, he was from the Güčügüt clan of Naimans. He conquered Yenisei Kyrgyz with his elder brother Naershi Tayang and succeeded him sometime. After Yelü Dashi's death 1143, he became independent, he supported Kerait ruler Toghril's brother Erke Qara against him in 1174. After his death Naiman khanate were divided into two factions ruled by his sons, he was married to Gürbesu and several other wives with whom he had at least two sons: Taibuqa known as Tayang khan Buyruq khanGürbesu married to his step-son Taibuqa in a levirate marriage. He was reported be a man of honor among Naimans according to The Secret History of the Mongols