* Orbit the Sun: They all travel in an elliptical path around our star, the Sun.

* Have cleared their neighborhood: They are the dominant gravitational force in their orbital region, meaning they have cleared away most other objects in their path. This is a defining characteristic of a planet.

* Are spherical: They are all massive enough for their own gravity to pull them into a nearly spherical shape.

* Do not produce their own light: They reflect sunlight, making them appear luminous.

While these are the main characteristics shared by all eight planets, there are also some additional similarities:

* Composed of rock and/or gas: They are not solid bodies like the Earth, but rather made up of various combinations of rock, ice, gas, and liquids.

* Have a variety of moons: Most planets have at least one moon, some have dozens!

It's important to note that these are the general characteristics. Each planet has its own unique features and composition, making our solar system incredibly diverse and fascinating!