- Perseids
The Perseids (pronEng|ˈpɝsiːɨdz pûr'sē-ĭdz) is a prolific
meteor shower associated with thecomet Swift-Tuttle. The Perseids are so called because the point they appear to come from, called the radiant, lies in theconstellation Perseus. Meteor showers occur whenEarth moves through a meteor stream. The stream in this case is called the Perseid cloud and it stretches along the orbit of the CometSwift-Tuttle . The cloud consists of particles ejected by the comet as it passed by theSun . 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 rate of meteors originating from this filament is much higher than for the older part of the stream.Observation
The 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 medieval Europe, the Perseids came to be known as the "tears of
St. Lawrence ."The shower is visible from mid-July each year, with the greatest activity between August 8 and 14, peaking about
August 12 . 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 thenorthern hemisphere .2007
The shower peaked on the new-Moon night of Sunday–Monday,
August 12 –August 13 and had an observed ZHRmax = 93 [http://www.imo.net/live/perseids2007/]2008
The Perseids were active from July 17 to August 24, 2008. On August 13th, the observed ZHRmax was 116 (at 20:10 UT) [http://www.imo.net/live/perseids2008/]
ee also
*
Meteor shower s
*List of meteor showers Notes
External links
* [http://www.revver.com/watch/442660 Timelapse movie of the 2007 Perseid Meteor shower]
* [http://science.nasa.gov/headlines/y2004/25jun_perseids2004.htm NASA website on the Perseid shower of 2004]
* [http://science.nasa.gov/headlines/y2005/22jul_perseids2005.htm NASA website on the Perseid shower of 2005]
* [http://science.nasa.gov/headlines/y2006/07aug_perseids.htm NASA website on the Perseid shower of 2006]
* [http://science.nasa.gov/headlines/y2007/11jul_greatperseids.htm NASA website on the Perseid shower of 2007]
* [http://science.nasa.gov/headlines/y2008/22jul_perseiddawn.htm NASA website on the Perseid shower of 2008]
* [http://meteorshowersonline.com/perseids.html Gary Kronk's Meteor Showers page]
* [http://www.shadowandsubstance.com/ animation of this event at Shadow and Substance.com]
Wikimedia Foundation. 2010.
