This satellite generates AMVs every 10 minutes and has been integrated into the Goddard Earth Observing ... used to estimate motion between two image frames based on the apparent motion of ...

Because Mercury’s orbit is only 88 days long, compared to 365 for Earth, the phenomenon of Mercury in apparent retrograde motion happens three to four times a year. In the astrology world ...

Then, an inner planet (Mercury) moves faster than an outer planet (like Earth), resulting in "apparent retrograde motion" — apparent because Mercury, speeding around our star at over 100,000 mph ...