Thor categorically denies that they belong to the Asgard. Jupiter's nothing but a big honkin' gas giant - there's nothing there to battle or cruise except that Earth-sized diamond at the core of the planet. And it costs too much in fuel to overcome gravity's pull to make a pleasure cruise to Jupiter profitable.
Besides, Thor already has a diamond ring - 725 carats, princess cut, mounted on tritanium. He uses it to carve rude graffiti on the portholes and to attract girls.
Now there have been some unscrupulous alien races offering Jupiter package tours. But since the end result of a Jupiter day trip is that you will be instantly crushed into your component protoplasm and die, sales have been sluggish. As in anything else in life, you get what you pay for.
So it wasn't Thor. And you can't prove it was.
Wild guess: Stargate-SG1 fan? < snicker >
Question: What do you think of the new Stargate Atlantis? I like it myself.