"I was wondering if Jupiter would look that big from one of it's moons, and so the moon being really big (being a gas giant I guess Jupter has not much pull?)" Errm .. if you are going for reality, then be aware that Jupiter (and Saturn, which is smaller), although made up of gases (except possbly at the core) actually mass much greater than the Earth. Jupiter's gravitational pull is enormous. (It's sometimes referred to as a "failed star", being not far from the mass limit which starts the gas to implode under it's own gravity, thus starting ignition - as happened with our own sun). Jupiter's moons (at least the nearer ones) are greatly affected by Jupiter's gravity (as skiwillgee states). And Gas Giants are amorphous - they have no solid surface, so no crater impacts, rock-like formations etc.. OTOH - if you're NOT going for reality (hey, this is sci-fi/fantasy!), then maybe the "Planet" is really a moon, which by some freak of nature (and, let's face it there are enough of them about, especially in politics - but I won't go there), ended up as a thin skin of rock over a hollow, vacuum surface:-)) (The rock was molten at 1st, with a bubble of air inside; the heat of the rock expanded the air and gradually cooled and solidified...or something like that. Not scientifically sound, but semi-plausible) :-)) Cheers, Diolma