See Also: Q: What is the origin of the word ... that we no longer need to rely on the simple definition from past millennia that an object is a "planet" if it moves against the background of ...

Officially, Pluto is no longer a planet ... astronomers say. The word "planet" originally described wanderers of the sky that moved against the relatively fixed background of star.

Officially, Pluto is no longer a planet ... astronomers say. The word "planet" originally described wanderers of the sky that moved against the relatively fixed background of star.