I've been watching this thing all day long. Might as well put it in a nice easy-to-find location so I can view it from anywhere.
Lightning! In slow motion! It turns out that the dancing sparks are called leaders, discharges originating in the negatively charged thundercloud and following ionized air, eventually drilling down to a positive charge (the ground) and creates a discharge path that we see as the big bright blinding and really really awesome bolt of lightning. I must harness this power.
For all the beautiful thunderstorms I've seen growing up in Texas, I've apparently never seen the mechanics of lightning before. Fascinating stuff.
From Today's Big Thing.