An Illusion
However, because the spheres don’t appear to be very large, you may have to concentrate to see them. That’s actually untrue! Keep in mind that some of them are hundreds of feet in the air, so what you see on the ground isn’t an accurate picture of their real size.
These red balls are known to have a diameter of 20 inches and some of the bigger kinds reach a diameter of 36 inches. Although these balls are rather big, they look tiny up high. Each ball usually weighs around 17 pounds.