The nine planets are the most striking members of the solar system. According to the distance from the sun, they are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. Except Mercury and Venus, other planets have their own moons, and the number is different.
There are many other small celestial bodies in the solar system family, including thousands of asteroids and their satellites, as well as hundreds of millions of comets and meteoroids. Among them, asteroids are mainly distributed between the orbits of Mars and Jupiter, forming a relatively dense asteroid belt.
Most members of the solar system family revolve around the sun along elliptical or circular orbits, but some comets have parabolic or hyperbolic orbits. Most planets rotate in the same direction as the revolution, but some planets rotate in the opposite direction, such as Venus and Pluto.
Asteroids, comets, meteoroids and interplanetary dust particles in the solar system can only be regarded as "tiny" compared with planets. Don't underestimate these "little guys". In interstellar travel, humans must first calculate the journeys of asteroids, comets and dense meteoroids so that spaceships and aircraft can avoid them and avoid colliding with them in space. When comets approach the sun, they drag their long tails and look very beautiful and spectacular in the sky. Meteoroids in the solar system also orbit the sun in elliptical orbits. Some meteoroids are attracted by the earth, break into the earth's atmosphere, and rub with the atmosphere to generate heat and glow. This is the meteor we saw. Some meteoroids are large in size and fall to the ground after burning in the atmosphere. It's called a meteorite or meteorite.