the planet you are looking for is Pluto it is about the same size as its moon and now scietist no longer call it a planet
possibly it may it may not the solar system is a complexmind that cant be controlled we can only guess
may be
None of the planets pass out of our solar system. The orbits of the planets, irregular as they may be IS the solar system.
Jupiter is the largest planet in our solar system.
Neptune is the eighth planet from the Sun. You may say it is the last planet if you exclude Pluto.
"The 5 planets" in the question is wrong. There are 8 known planets, not 5, in our Solar System. The question may mean "5th planet" (from the Sun). Jupiter is the 5th planet.
Nothing. You may be referring to the planet Pluto, which was DISCOVERED in 1930, but it had in all probability been part of the solar system since the Sun ignited 4.5 billion years ago.
There is no "second smartest" planet in the solar system. By a stretch, Earth may be regarded as the "smartest" due to the presence of intelligent life. However, since it appears that no other planets in the solar system have life, they are all equally "not smart."
There are nine, excluding Pluto which has been demoted to a dwarf planet.
The planet that you may mean was the Planet Pluto, which was recently reclassified as a Dwarf Planet. It is also believed by many that what is now the asteroid belt, was once a planet.
When Pluto was still officially considered a "planet" in our solar system, it and it's moon Charon were considered by many to be a double planet system. Whenever a moon constitutes a considerable percentage of the host planet's mass, it may be considered a double planet system. For this reason, some consider the Earth and our moon to be a double planet system. Our system has by far the greatest planet to moon mass ratio; about 6:1. As for planets outside our solar system, I cannot say. Though there are many out there.
It is very unlikely there are unknown planets in our system,, although beyond the kuiper belt, at the very far edge of our solar system some believe there may be another planet. It is referred to as "Planet X".