http://www.khabrein.info/index.php?option=com_content&task=view&id=29341&Itemid=62&limit=1&limitstart=1 November 18: Meteor shower November 2009 video and Leonid meteor shower 2009. Leonid meteor shower was fascinating to say the least. I have rarely experienced such bright particles glowing in the sky. The reason may be the fact that it was a clear sky and me being at the right place. You cannot experience good meteor shower if the place is cloudy or if you fail to reach the place in advance. Meteoroid streams are caused by the debris of comets. The stuff of comets comes from interstellar space where the materials are assembled in the atmospheres of stars and in the dense molecular clouds of gas and dust between the stars. The comets are built of that material and were formed in the outer parts of the solar system, in regions beyond Saturn's orbit, at the time of the birth of our solar system. How meteoroids leave the comet is a matter of research. When comets approach the Sun, the ices evaporate and the dust particles are ejected into orbit in geyser like fountains. Comet nucleus is the mountain of ice and dust (mostly dust) that is at the center of a comet. This picture is the nucleus of comet 1P/Halley. The nucleus of this comet was photographed by the Giotto Satellite in 1986. It has a 2-3 times larger nucleus than 55P/Tempel-Tuttle. Comet 55P/Tempel-Tuttle is the parent of the Leonid meteoroid stream. The orbit is shown in the graph above. Persistent train is the long enduring emission that remains in the path of a bright fireball once the afterglow has faded. Persistent trains can last for 1-30 minutes (typically 4-6 minutes) at an apparent brightness of +4 to +5 magnitude. The optical light of these long enduring trains is from Na (sodium) and FeO (iron oxide), from airglow-type chemistry of the recombination of oxygen atoms and ozone molecules that is catalised by sodium and iron atoms. Persistent trains last long enough to enable telescopic studies of the path of a meteor. Upper atmosphere winds distort the shape of the train. Meteors are better known as "shooting stars": startling streaks of light that suddenly appear in the sky when a dust particle from outer space evaporates high in the Earth's atmosphere. We call the light phenomenon in the atmosphere a "meteor", while the dust particle is called a "meteoroid". * Size: Most visible Leonids are between 1 mm and 1 cm in diameter. For example, a Leonid meteor of magnitude +5, which is barely visible with the naked eye in a dark sky, is caused by a meteoroid of 0.5 mm in diameter and weights only 0.00006 gram. * Speed: That tiny particle can cause a light so bright that it can be seen over distances of hundreds of kilometers. The reason is the astronomical speed of the meteoroids. Just before they enter the Earth's atmosphere, Leonid meteoroids travel at 71 kilometers per second, or some 2,663 times as fast as a fast pitch in baseball, or, if you want, around the Earth in 3.8 minutes! * Source of light: When meteoroids enter the Earth's atmosphere, they collide with numerous air molecules. Those collisions sputter away the outer layers of the particle, creating a vapor of sodium, iron and magnesium atoms. In subsequent collisions, electrons are knocked into orbits at larger mean distances from the nucleus of the atoms. When the electrons fall back to their rest positions, light is emitted. This is the same process as in gas discharge lamps. * Colors of meteors: The color of many Leonids is caused by light emitted from metal atoms from the meteoroid (blue, green, and yellow) and light emitted by atoms and molecules of the air (red). The metal atoms emit light much like in our sodium discharge lamps: sodium (Na) atoms give an orange-yellow light, iron (Fe) atoms a yellow light, magnesium (Mg) a blue-green light, ionized calcium (Ca+) atoms may add a violet hue, while molecules of atmospheric nitrogen (N2) and oxygen atoms (O) give a red light. The meteor color depends on whether the metal atom emissions or the air plasma emissions dominate.