You're likely thinking of asteroids, which are rocky, irregularly shaped objects that orbit the Sun. They are not planets, but rather small, leftover remnants from the early solar system.

Here's why we don't call them tiny planets:

* Size: Asteroids are much smaller than planets. They range in size from pebbles to hundreds of kilometers across.

* Shape: Asteroids are not spherical like planets. They are irregular and often have odd shapes.

* Composition: Asteroids are mostly made of rock and metal, while planets are made of a variety of materials, including rock, gas, and ice.

* Gravitational influence: Asteroids have a very weak gravitational field, unlike planets which have enough gravity to hold onto their own atmosphere.

Asteroid Belts:

* Asteroid Belt: The most famous asteroid belt is located between the orbits of Mars and Jupiter. This belt contains millions of asteroids.

* Trojan Asteroids: There are also asteroid groups called Trojans that share an orbit with a larger planet, but stay ahead or behind the planet at certain points in the orbit. Some Trojans orbit Mars and others orbit Jupiter.

So, while they are not tiny planets, asteroids are fascinating objects that hold clues to the formation of the solar system.