Here's a breakdown:

* Planets: Planets are large celestial bodies that orbit a star. They have enough gravity to be nearly round and have cleared their orbital path of other objects. Planets can be vastly different in size, but even the smallest planet, Mercury, is much larger than any known comet.

* Comets: Comets are small, icy bodies that orbit the Sun. They are made of ice, dust, and rock. Comets are typically only a few miles across, while planets can be thousands of miles in diameter.

Think of it this way:

* Imagine a planet like Earth as a basketball.

* A comet would be about the size of a pebble.

So while both planets and comets orbit stars, they are very different in size and composition.