What is the shape of the Moons orbit around the Sun?
The center of mass of the Earth-Moon binary pair is an ellipse, NOT the orbit of the Earth OR the Moon, which both are ellipse shaped but with a sine wave component. In essence, the Earth “wobbles” around the center of mass, as does the Moon. So, the path around the Sun becomes a ripple or wavy shaped ellipse with a peak and valley every 27.3 days, which is the orbital period of the Moon about the Earth. The Earth has a corresponding ripple or wavy shape in opposition to the shape of the Moon’s path. It took me a long time to figure this out for myself way back when in grade school. We had an animated model which showed the moon making circles around the Earth and incorrectly showed the Moon stopping and moving backwards relative to the Sun. Imagine a three lane road with you in a car in the center lane. A car is immediately to your left moving faster than you are. When the other car gets ahead of you, it crosses all three lanes and slows until it falls behind you at which time it cros
