- All the planets orbit the Sun in elliptical orbits
venus is retrogade or rotates backwards
- Almost all (perhaps all if one excludes Pluto) orbit on the same plane.
- They mostly all rotate in the same direction.
- Most have moons.
- They all contain mostly the same elements, except that the closer the planet is to the sun the less lighter matter they tend to have.
- They are all planets and are in the solar system.