the one i can think of off the top of my head is Jupiter. its the biggest planet and the fifth away from the sun. scientists believe it has no ground and always has some type of bad weather.
J
joccund
Jupiter
joules
Jerk
Jaw
jonquil
Right now there is I believe only one planet that begins with the letter J that is "Jupiter". In Earth's Solar System which is the largest planet in our solar system.
Jovial jewel
Jaunt.
Jovial
jab jack jade