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Perseids

The Perseids (play /ˈpɜrsiːɨdz/) are a prolific meteor shower associated with the comet Swift-Tuttle. The Perseids are so-called because the point from which they appear to come, called the radiant, lies in the constellation Perseus. The name derives in part from the word Perseides (Περσείδες), a term found in Greek mythology referring to the sons of Perseus.

The stream of debris is called the Perseid cloud and stretches along the orbit of the comet Swift-Tuttle. The cloud consists of particles ejected by the comet as it travels on its 130-year orbit. Most of the dust in the cloud today is around a thousand years old. However, there is also a relatively young filament of dust in the stream that was pulled off the comet in 1862.[1] The rate of meteors originating from this filament is much higher than for the older part of the stream.

The Perseid meteor shower has been observed for about 2000 years, with the earliest information on this meteor shower coming from the Far East.[2] Some Catholics refer to the Perseids as the "tears of St. Lawrence", since 10 August is the date of that saint's martyrdom.[3]
A Perseid in 2007.

The shower is visible from mid-July each year, with the peak in activity being between August 9 and 14, depending on the particular location of the stream. During the peak, the rate of meteors reaches 60 or more per hour. They can be seen all across the sky, but because of the path of Swift-Tuttle's orbit, Perseids are primarily visible in the northern hemisphere. As with all meteor showers, the rate is greatest in the pre-dawn hours, since the side of the Earth nearest to turning into the sun scoops up more meteors as the Earth moves through space. In 2009, the estimated peak Zenithal Hourly Rate was 173,[4] but fainter meteors were washed out by a waning gibbous moon.


Year Perseids active between Peak of shower
2011 July 17 - August 24 August 13 (ZHRmax 100) [5]
2010 July 23 – August 24 August 12 (ZHRmax 142) [6]
2009 July 14 – August 24 August 13 (ZHRmax 173)
2008 July 25 – August 24 [7] August 13 (ZHRmax 116) [7]
2007 July 19 – August 25 [8] August 13 (ZHRmax 93) [8]
1972 August 12: reported to be the most active shower in recorded history [9]

References

^ Dr. Tony Phillips (June 25, 2004). "The 2004 Perseid Meteor Shower". Science@NASA. Retrieved 2010-03-12.
^ "Perseids". Meteorshowersonline.com. Retrieved 2009-08-12.
^ Monday, Aug. 23, 1926 (1926-08-23). "Science: Tears of St. Lawrence". TIME. Retrieved 2009-08-12.
^ "Perseids 2009: visual data quicklook". Imo.net. Retrieved 2009-08-11.
^ "How to See the Best Meteor Showers of the Year: Tools, Tips and 'Save the Dates'". nasa.gov. Retrieved 2010-11-16.
^ "How to See the Best Meteor Showers of the Year: Tools, Tips and 'Save the Dates'". nasa.gov. Retrieved 2010-08-12.
^ a b "Perseids 2008: visual data quicklook". Imo.net. Retrieved 2009-08-11.
^ a b http://www.imo.net/live/perseids2007/
^ Stone, Steve (2006 11 08). "Bright sky could dim nighttime viewing of meteor shower". AccessMyLibrary.com. Retrieved 2009 12 08.

Meteor showers

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