I always knew planes made these vortices when going through clouds/smoke, but I thought they were just tip vortices. Looking further into it, they are way too big to be tip vortices, so they had to be from the wing (trailing edge). I thought that the vortex from the wing was positioned perpendicular to the trailing edge of the wing, the same way tip vortices are perpendicular to the tip of a wing, if that makes sense. In that case, the vortex would not be parallel to the trailing edge of the wing, like in this photo. (Try to put some of it into layman's terms if you can, not a professional, thanks!)
(last thing, I've heard they rotate counter-clockwise, why is that?)