Why does the trail of an object in US go crazy when I zoom in on a fast-moving object (my object is going 843 Light Years per second)?
This is a known bug. Bla was on the right track with his comment "too many decimals". It has to do with a lack of precision (not enough decimals) in the placement of the trail (or the object) into the 3D world. In the current version (and also v2 beta 1) you can also see this shaking if you set another object as the 'center' and zoom in on something far away. The body shaking, but not the trail issue, has been fixed in v2 beta 2.