Thanks for the links. When I saw this before I read where it was my first thought was New Grange, then it seemed that I remembered seeing something similar at Malta. For the heck of it I checked Gloria Farley’s, “In Plain Sight”, but there was nothing similar. If her finds cover 3,000 to 1,000 years ago, and these circles cover 4,000 to 6,000 years ago, that would make sense.
Surprisingly, comets do not always appear as sweeping brooms in the sky. When viewed at the correct angle and orientation, while the comet is outgassing appropriately, a comet can actually appear as a spiral "pinwheel." Below are some photos and a short movie of comet Hale-Bopp in 1997 when it was in spiral display.
SAHARA
TARXIEN TEMPLE MALTA
TUCSON ARIZONA