1. They are all celestial bodies: All three are objects in space, governed by the laws of physics and gravity. They exist within our solar system, though their roles and sizes are very different.
2. They all have gravity: Every object with mass has gravity, and these three are no exception. Gravity is what keeps the Moon in orbit around the Earth and the Earth in orbit around the Sun.
3. They all have a history: While their formation stories differ, they all have been around for billions of years, going through various stages of evolution and change. We can study their past and learn about the history of our solar system.
