One comment:
What you are seeing is not a trail from the ground, but a trail over the horizon. It was not launched it was reentering. Its hard to gauge with no frame of reference, but it looks like it was huge and in really high orbit. For it to trail that far means it was either designed to survive reentry, or incredibly dense. You can see it drop part of its trail about halfway through, meaning it punched through a layer of atmosphere and pressure changed rapidly, or possibly it intentionaly slowed down, or that it dropped a part of its structure or broke up thus quickly changing size. I am inclined to believe it was an unintentional reentry, the Chinese are up to all kinds of crap, and historically their space launches and operations have always been over their own soil rather than over the ocean like the rest of the civilized world. There is no human technology I know of that can slow a man made object reentering that quickly, the shuttle circles the planet like 3 times to shave off speed.
