It’s actually because planets are fairly large. You can actually see them on the back of your eye. It’s a bit like having 100 stars all very close togther. All those 100 stars will be twinkling. On average some of them are going to be twinkling brighter and some of them are going to be darker than average. They tend to twinkle less when you see them all together. If 20 of them are going to be brighter and 20 of them are going to be darker then on average it’s not going to twinkle very much. |