A planet is a large space object that revolves around a star. There are 8 planets (plus dwarf planets)
Here's an acronym to help you remember the order of the planets:
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The planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The dwarf planet is Pluto
Definition of Asteroids:
Minor planets, most of which circle the Sun in a region known as the Asteroid Belt.
Asteroids are made of rock and metal (mostly Nickel and Iron)
The Sun is the center of the Solar system, being the largest and hottest star.
Definition of Comets:
Dirty snowballs that are made of mostly ice and rock. They usually orbit the Sun at great distances
The moon is also part of the Solar system and it is Earth's only natural satellite
Definition of Stars:
Huge glowing balls of gas, some are big but most are smaller than the Sun
Other objects that exist in our Solar system include: asteroids, comets, stars, etc.