More evidence that the comet is rotating or spinning around an axis. This is just over 3 hrs of time and the angle of rotation in that time looks to be about 5 degrees. So, if we take 360 degrees and divide by 5 degrees we get 72, which is how many 3 hr periods to total one rotation. 72 times 3 hrs = 216 hours total time for 1 rotation. 216 divided by 24 hrs = 9 days. Bingo!