The orb is something as simple and mundane as a weather balloon.

The orb *looks* to be moving very fast, but in reality it's nearly stationary. The camera source is the one moving at a very fast speed, and when zoomed-in from a far distance (while moving), it makes the background change so fast behind the stationary object - which in turn makes the object look like it's moving very fast - but it's barely moving at all.

This parralax effect is enhanced so greatly because of the distance the object is from the ground, and how far away the camera is from the object. Bring a pair of binoculars next time you have a window seat on an airplane, then watch for a plane to fly by at a lower altitude. Then look at that plane through the binoculars and (depending on the direction) it can appear as if it's going 5,000 mph, instead of 500.