Perseids
From Free net encyclopedia
The Perseids are a prolific meteor shower associated with the comet Swift-Tuttle.
The shower is visible from mid-July each year, but the bulk of its activity falls between August 8th and 14th with a peak on August 12th. During the peak, rates of a hundred or more meteors per hour can be registered.
Meteor showers can be seen when Earth moves through a meteor stream. The stream in this case is called the Perseid cloud and it stretches along the orbit of the Comet Swift-Tuttle. The cloud is comprised of particles ejected by the comet as it passed by the Sun. Most of the dust in the cloud today is approximately a thousand years old.
However, there is also a relatively young filament of dust in the stream that boiled off the comet in 1862. The approximate rate of meteors originating from this filament is much higher than normal.
The Perseids are called so because the point they appear to be coming from, called the radiant, is in the constellation of Perseus. However, they can be spotted all around the sky. Because of the positioning of Swift-Tuttle's orbit, Perseids are mostly visible on the northern hemisphere.
The famous Perseid meteor shower has been observed for about 2000 years, with the first known information on these meteors coming from the far east. In early Europe, the Perseids came to be known as the "tears of St. Lawrence."
"Saint Lawrence was tortured and killed in Rome on August 10, 258 during the reign of the anti-Christian emperor Valerian... Citing Quetelet, 'a superstition has 'for ages' existed among the Catholics of some parts of England and Germany that the burning tears of St. Lawrence are seen in the sky on the night of the 10th of August; this day being the anniversary of his martyrdom.'" - Mark Littmann
To experience the shower in its full, one should observe from a point far outside any large cities, where stars are not dimmed by the cities' glow.
See also
External links
- NASA website on the Perseid shower of 2004
- NASA website on the Perseid shower of 2005
- Gary Kronk's Comets and Meteor Showers pagecs:Perseidy
de:Perseiden et:Perseiidid es:Perseidas fr:Larmes de Saint Laurent it:Perseidi he:פרסאידים nl:Perseïden ja:ペルセウス座流星群 pl:Perseidy ru:Персеиды sk:Perzeidy