A Planet is currently defined by the International Astronomical Union as an interstellar object that must meet three criteria:
- It must orbit a star (in our cosmic neighbourhood, the Sun, or Sol, is the star).
- It must be big enough to have enough gravity to force it into a spherical shape.
- It must be big enough that its gravity has cleared away any other objects of a similar size near its orbit around the Sun.
It is likely that our definition of the word *Planet* will evolve over time as we explore the cosmos.