And you can put space in a jar and make magic out of it.
Yeah. Or if you dig in the meteors, you can sometimes find magic sources.
But you would Die without a Helmet. Dirt blocks would float away if not connected to something connected to the ground, or connected to something thats connnecting to the ground.
And space creepers.
Well, we can go with the air helmet and Oxygen tank to go with space, and Notch could make a simple space rock block.
Some monsters should be UFO's, Minecrawlers (Evil machines) and maybe space creepers would do.