The Known World
In order from the sun, the Solar System’s planets include:
Vulcan, a hypothetical planet whose orbit is nearest to the Sun. Its existence is not recognized by science and it may or may not exist.
Mercury is the nearest observable planet to the Sun.
Venus is the planet closest to the Earth, and the most Earth-like in size.
Earth is the home planet of humanity and the center of the Known World.
Counter Earth is a hypothetical planet invisibly sharing Earth’s orbit on the opposite side of the Sun.
Mars, the red planet, is the next out from the Earth.
Jupiter is the largest planet in the Solar System, with several good-sized moons.
Saturn is the next-largest planet, and has the Solar System’s most impressive rings.
Uranus is another gas giant.
Neptune is yet another gas giant.
Pluto is a tiny planet with an eccentric orbit.
Xena is the most distant planet yet discovered.