Ahhh aardbei is earth berry?
In English we would say "We live on planet Earth" and wouldn't insert the "the" -- is the "the" necessary in Dutch in this case, or does this sentence mean "We live on the planet [called] Earth" or something?... Kinda awksauce.
It is necessary in Dutch. That particular example is an exception in the English language. Languages rarely translate word for word.
You can say either, really. I've heard it referred to as both "The planet earth" and "planet earth." We're not the only planet :D
I'm the opposite of you. I'd much prefer to say "the planet Earth" and I find "planet Earth" slightly awkward.