The Moon that you have often seen as seemingly motionless in the sky is actually hurtling around the Earth at more than four times the speed of a jet plane. Only its great distance, fifty Earth-diameters away, makes it seem stationary. At this speed, it takes the Moon almost 30 days to complete one orbit of the Earth.
So the Moon’s orbit is very big – quite a bit larger than most people realize. It may surprise you to learn, then, that the entire orbital path of the Moon could fit inside the Sun. In fact, the Sun is twice as far across as the Moon’s orbit! Its diameter is about a hundred Earth-diameters.
Amazingly, though, the Sun is absolutely tiny compared to the largest stars. The size of the largest known star is about 2600 times the size of the Sun, roughly comparable to the size of the orbit of Saturn!