I'm convinced it's a hoax. This guy has produced a whole series of videos debunking these. They're pretty convincing http://www.youtube.com/watch?v=uKR1OIQFsFg [video=youtube;uKR1OIQFsFg]http://www.youtube.com/watch?v=uKR1OIQFsFg[/video]
All the ball lightning I have seen doesn't move like that, but most of the ball lightining I have seen was from when I worked in a forest service fire watch tower and it was just floating around the room. You had to make sure you didn't move because it would get attracted to the vacuum behind you and chase you around the tower.
It's one case where you have to keep up with the latest news. What's most impressive about that number, is that those were all found/postulated in just this decade. They have actually only found something like 10k or 20k planets, but they have only searched like 1/40 of the sky.
