Hmmm. Provided it was not a spontaneous phenomenon native to the planet (which seems a remote possibility) it was likely something to do with a meteorite. I always thought that a meteorite was thought to have caused the effect (which was centered in the air by the way) but the HOW of it remains a mystery. Still, i'm not really high on it. Please fill in other interesting impacts -) Anders Törlind     Here's a question; are bits of stuff that fall on other planets also called meteorites? Or is this a geocentric term? Dictionary.com seems to suggest this, but doesn't say it explicitly one way or the other.  21:49 Jul 23, 2002 (PDT)