What are three characteristics of planets

- - Planets are all very nearly spherical in shape.

- - Planets orbit the Sun, or whatever other star they belong to, in

an orbit that is an ellipse, with the star at one focus of the ellipse.

- - Planets rotate, with their axis of rotation usually, but not always,

being pretty close to perpendicular to the plane of their orbit.

Some other characteristics are:

- - whether the planet has an atmosphere or not

- - the temperature at the surface of the planet

- - the planet's composition and density