by Et in Arcadia ego » Sun Aug 06, 2006 4:31 pm
<!--EZCODE QUOTE START--><blockquote><strong><em>Quote:</em></strong><hr>Because it's energy leaving?<hr></blockquote><!--EZCODE QUOTE END--><br><br>Nope. re:<br><br>"Positive lightning makes up less than 5% of all lightning. It occurs when the leader forms at the positively charged cloud tops, with the consequence that a negatively charged streamer issues from the ground. The overall effect is a discharge of positive charges to the ground. Research carried out after the discovery of positive lightning in the 1970s showed that positive lightning bolts are typically six to ten times more powerful than negative bolts, last around ten times longer, and can strike tens of kilometres/miles from the clouds. The voltage difference for positive lightning must be considerably higher, due to the tens of thousands of additional metres/feet the strike must travel. During a positive lightning strike, huge quantities of ELF and VLF radio waves are generated.<br><br>As a result of their greater power, positive lightning strikes are considerably more dangerous. At the present time, aircraft are not designed to withstand such strikes, since their existence was unknown at the time standards were set, and the dangers unappreciated until the destruction of a glider in 1999.[3]<br>Intracloud lightning.<br>Enlarge<br>Intracloud lightning.<br><br>Positive lightning is also now believed to have been responsible for the 1963 in-flight explosion and subsequent crash of Pan Am Flight 214, a Boeing 707. Subsequently, aircraft operating in U.S. airspace have been required to have lightning discharge wicks to reduce the chances of a similar occurrence.<br><br>Positive lightning has also been shown to trigger the occurrence of upper atmosphere lightning. It tends to occur more frequently in winter storms and at the end of a thunderstorm.<br><br>An average bolt of positive lightning carries a current of up to 300 kiloamperes (about ten times as much current as a bolt of negative lightning), transfers a charge of up to 300 coulombs, has a potential difference up to 1 gigavolt (a billion volts), lasts for hundreds of milliseconds, and dissipates enough energy to light a 100 watt lightbulb for up to 95 years."<br><br><!--EZCODE AUTOLINK START--><a href="http://en.wikipedia.org/wiki/Lightning#Positive_lightning">en.wikipedia.org/wiki/Lig..._lightning</a><!--EZCODE AUTOLINK END--> <p>____________________<br>Some are born to sweet delight, some are born to endless night.</p><i></i>