there are inner planets and outer planets. the inner planets are the first four planets that are closer to the sun. they are made of rock. the remaining four (not including pluto, because it is a dwarf planet, not a real planet according to scientists- which i dont thinki is correct i htink it should be a normal planet- but who's asking for my opinion anyway?!) are further away from the sun and are made of gas and bits of rock, insteaf of being solid rock. these are the outer planets
EDIT: Pluto is classified as a dwarf planet because it is a keiper belt object. It is essentially an asteroid in the very outer reaches of the solar system. Its orbit is eccentric and it does not follow the same gravitaitonal behaviours as a planet. It would simply be termed a keiper belt object like the 1000s of other bodies in the keiper belt but due to its large size (in comparison to the other objects) and classical description as a planet it was reclassified as a dwarf planet.
inner planet.
It is a outer planet.
Mars is an inner planet.
Outter planet (gas giant)
It is not a planet, but if it was it would be an inner planet because it is before the Main Asteroid Belt, in the line of planets from the Sun.
The four inner planets are:MercuryVenusEarthMarsThe four outter planets are:JupiterSaturnUranusNeptunePlutoPluto was a planet but it isn't anymore because it doesn't have the required characteriztics of a planet.
Life
Pluto is no longer classified as a planet, but it was formerly considered an outer planet because it is beyond the asteroid belt.
Mars is an inner planet. It lies on the side of the asteroid belt which contains Earth, Venus, and Mercury. On the other side of the Asteroid Belt are Jupiter, Saturn, Uranus, Neptune, Pluto - which is no longer considered to be a planet, but a dwarf planet. These are the outer planets.
The outter core is liquid.
Men havent set foot on any planet. Not anything in outter space except for the moon.
Jupiter is an outer planet - it is outside the orbit of the Asteroid Belt.Inner planets:MercuryVenusEarthMarsOuter planets:JupiterSaturnNeptuneUranus