Someone's made a circular bevel that's semi-transparent and
placed it on top of a masked flat map which tweens from right to
left. That's why it's not believable. The continents are not
changing shape as they "rotate" around the globe. It's a quick fix
but not a convincing animation.
I'm not sure there is much you can do unless you import the
frames (minus the bevel) into Illustrator or Photoshop and
individually apply a bloat filter to each. Then reimport them back
into Flash as frame-by-frame animations. Or...
Go to istockphoto.com and purchase a more realistic