An accountancy practice <a href=" http://www.ohword.com/environmental-policies-in-the-last-5-years-2008---2012/ ">alongside custom essay station originate envelope</a> Those dust grains come courtesy of Comet Swift-Tuttle, which circles the sun once every 133 years and leaves behind a debris trail. (Comets are basically dirty snowballs that develop tails when they approach the sun and start to melt. Different ones are responsible for other regular meteor showers, such as AprilÂ’s Lyrids brought by Comet C/1861 G1 Thatcher, and NovemberÂ’s Leonids brought by Comet 55P/Tempel-Tuttle).