What is meant by “Inner” and “Outer” Solar System?

The Inner Solar System refers to the region between the Sun and Mars where the planets are relativity close together. Beyond this is the Outer Solar System, where the planets are spaced relatively wider apart.

What are the main constituents of the Solar System?

The solar System consists of the Sun and all the heavenly bodies that orbit it, such as the planets, moons, asteroids, comets, etc.

The term Solar System is also synonymously used to refer to the region of space occupied by the Sun and the other bodies of the Solar System.

Name the planets and their symbols.

The nine planets orbiting the Sun are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. Sometimes specific symbols are used to denote the planets.

Can a Heavenly body be a temporary member of the Solar System?

Yes. For example, a comet following a hyperbolic trajectory can enter the Solar System, go around the Sun Partially and leave the Solar System never to return.

Are the names of the planets usually mentioned in ascending order of their distance from the Sun?

Yes, up to Uranus. Pluto has a highly eccentric orbit which partially overlaps the orbit of Neptune. Sometimes Pluto is the outermost planet and at other times Neptune is the outermost one.

 So all the planets orbit the Sun in the same direction?

Yes.

Do all the planets rotate about their own axes white orbiting the Sun?

Yes.